Important Pet Information

Often, it is the spread of a cancer that causes the greatest problems. When a cancer has spread in this fashion, it is said to have metastasized. Some cancers lack the ability to metastasize, but may cause significant damage due to growth and invasion into local tissues. Tumors that do not metastasize and are not invasive are considered benign. Tumor is a general term for cancer whether it is benign (“good cancer”) or malignant (“bad cancer”). Oncology is the branch of medicine dedicated to the study of cancer, and the people treating your pet at WSU are Oncologists and Oncology nurses.

Tumor Evaluation (Work-up): Tumor Staging

The first task for the veterinarian is to determine the extent of the tumor which is a process called tumor staging. Staging information is vital for several reasons including:

1. determination of your pet’s prognosis (i.e., the expected outcome for your pet from the illness) and,
2. formulation of a plan for treatment.

To gather information that can help to determine the extent of the cancer, your veterinarian will need to evaluate your pet by several methods. These usually include blood tests (e.g., blood count, chemistry profile), urinalysis, radiographs (x-rays), tissue aspirate (a sample taken with a fine needle) and biopsy. Tests which your veterinarian may have performed might be repeated at WSU due to the changing nature of your pet’s illness. In addition, as indicated for specific patients, other testing procedures may include: ultrasound, specialized radiologic studies (e.g., CT scan, dye contrast studies), bone marrow aspirate, lymph node aspirate, endoscopy (direct examination of the stomach, colon or bronchi with a specialized scope), and immunologic studies. It is important to note that medicine is not an exact science and despite these staging procedures, it is still possible to fail to recognize small sites of tumor or the presence of tumor in organs that are difficult to study.

Once the tumor staging has been completed, your veterinarian will better be able to discuss treatment options for your pet. The goal of such therapy will also be discussed. Tumors that have metastasized extensively are usually not curable. Therefore, the objective of therapy for these animals is palliation (i.e., afford relief of signs without providing cure, and possibly, prolong life). Localized tumors that are not deeply invasive have the best chance to be cured.

Cancer Therapy

There are several types of therapy used to treat cancer in dogs and cats at WSU. These include surgery, chemotherapy, radiation therapy, and immunotherapy. For some tumors, treatment will consist of a single type of therapy, while combination therapy may be recommended for other types of cancer or for animals with a more advanced stage of disease. On occasion, due to the rarity of a particular tumor, a precise treatment recommendation may not be known. In an effort to test newer (and hopefully more effective) forms of therapy, you may be asked to enroll your pet in an investigative clinical trial. The purpose of such a trial is to learn more about the specific type of treatment (that may be of value to humans and other pets with cancer) as well as hopefully providing a benefit to your pet. Only pet owners of animals with tumors for which there is no effective treatment, or tumors that have not responded to conventional treatment will be offered investigative therapy for their pets.

Should You Treat Your Pet?

Treating animals with cancer is not appropriate for every pet owner. It takes a strong commitment on the part of the owner. Therapy requires frequent trips to the veterinary hospital and can be expensive. For some forms of cancer treatment, once begun treatment is never stopped during the animal’s life although the frequency of these treatments can be decreased. Your veterinarian cannot do it alone since treating pets with cancer is truly a team effort and the pet owner is on the team. It is important for you to present your pet for treatment precisely when requested to do so by your veterinarian since the timing of cancer therapy is critical for obtaining an optimal outcome. In addition, medicines to be given to your pet at home should be administered by you exactly as instructed by your oncologist. Any abnormalities or problems you encounter should be reported to your regular veterinarian or oncologist promptly. Always feel free to ask questions and communicate with us.

Keep in mind your veterinarian is as concerned about the quality of your pet’s life as you are. The goal of the therapy is to keep your pet happy and minimize discomfort. Although some animals may experience transient discomfort from therapy, treatment of most pets with cancer can be accomplished without major distress or detraction from your pet’s enjoyment of life. Just because an animal has been diagnosed with cancer does not mean its life is immediately over. Your commitment to your pet and your veterinarians dedication to providing state-of-the-art care will work together to keep your pet as happy as possible.

• congenital malformation of the kidneys (birth defects)
• chronic bacterial infection of the kidneys with or without kidney stones (pyelonephritis)
• high blood pressure (hypertension)
• diseases associated with the immune system (e.g. glomerulonephritis, systemic lupus))
• acute kidney disease, for example poisoning with antifreeze, that damages the kidneys can lead to CKD

Often the cause of CKD is unknown.

Structure of the kidneys

The microscopic unit of the kidney is called the nephron. Each kidney contains thousands of nephrons. When the pet is young and healthy not all nephrons are working all of the time; some nephrons are held in reserve. As the animal ages or if the kidneys are damaged, some nephrons die and other resting nephrons take over the work of those that die. Eventually all the remaining nephrons are working. When there are no extra nephrons remaining and kidney damage continues the pet will start showing signs of CKD. Because of this stepwise loss of nephrons the kidneys are able to "hide" the fact that they are damaged until the damage is severe. When 2/3 of the nephrons have been lost the pet is no longer able to conserve water and the pet passes larger amounts of dilute urine. By the time a pet has an elevation in the waste product creatinine in its blood, 75% of the nephrons in both kidneys have been lost.

What do the kidneys do?

When blood flows through the kidneys, the kidneys act as a complex filter that removes from blood wastes that are generated from break down of food, old cells, toxins or poisons and many drugs that are given for treatment of other diseases. The wastes are removed with water as urine. Waste products than can be measured in the blood include creatinine and urea nitrogen but there are many other waste products that are not measured by blood tests. The kidneys also acts as a filter to keep "good" substances in the blood. The kidneys regulate the amount of water in the blood by excreting extra water and retaining water to prevent dehydration by varying the amount of urine that is produced. The kidneys help regulate blood pressure by saving or eliminating sodium based on how much sodium the pet is eating. The kidneys help regulate calcium and vitamin D which keep bones strong. The kidneys produce a substance that helps with the creation of new red blood cells. Because the kidneys have so many functions, when the kidneys are not working normally, there are many signs that the pet may show.

CKD is progressive

By the time the pet shows signs of CKD, the damage is severe. There is no cure for CKD. The remaining nephrons are working so hard that with time they will fail as well. CKD is usually fatal in months to years but various treatments can keep the pet comfortable and with a good quality of life for months to years.

Signs of CKD

Because the kidneys perform so many functions, the signs pets with CKD show can vary quite a bit. The signs may be severe or may be subtle and slowly progressive. Despite the chronic nature of the disease, sometimes signs appear suddenly. Some of the more common signs of CKD include:

• drinking too much (polydipsia) and urinating large volumes of urine (polyuria)
• the increased volume of urine in the bladder may lead to, or worsen incontinence (leaking urine), especially at night
• vomiting and/or diarrhea
• lack of appetite and weight loss
• general depression related to the elevation of waste products in the blood
• anemia resulting in pale gums and weakness due to a low blood count
• overall weakness from low blood potassium

Less common signs include

• weakened bones can result in bone fractures
• high blood pressure can lead to sudden blindness
• itchy skin from calcium and phosphorous depositing in the skin
• bleeding into the stomach or gut or bruising of skin

Signs you may see if you examine your pet include: dehydration, weight loss, pale gums and ulcers in the mouth.

The signs seen in pets with CKD and the findings on examination are not specific for CKD and may be seen with many other diseases so blood and urine tests are needed to make a diagnosis of CKD.

Diagnostic Tests

Abnormalities that are often seen on diagnostic blood and urine tests include:

• anemia without signs of a response by the body to the low blood count (non regenerative anemia)
• increased wastes that are normally removed by the kidneys (blood urea nitrogen [BUN] and creatinine)
• increased phosphorus
• calcium is often normal but can be elevated in some pets with CKD and rarely is decreased
• dilute urine
• +/- protein or bacteria in the urine

Sometimes bruising occurs where the blood sample was drawn as pets with CKD may have platelets that are less sticky than normal (normal platelets prevent bruising).

A diagnosis of CKD can usually be made based on the signs, physical examination and blood and urine tests but other tests may be performed to look for an underlying cause for the CKD and/or to "stage" the CKD.

Other tests that may be performed include

1. Determination of kidney size using abdominal radiographs (x-rays) or ultrasound
   What might this test show?  The kidneys in pets with CRD are usually small reflecting the death of a large number of nephrons. If the kidneys are large then certain causes for the CKD should be considered such as lymphoma (cancer) of the kidneys, or an uncommon disease called amyloidosis. Some pets with signs of kidney disease who have large or normal sized kidneys may have acute kidney failure rather than CKD. The treatment and prognosis for pets with acute kidney disease differs from the treatment and prognosis of pets with CKD.
2. Kidney biopsy
   What might this test show?  A biopsy is not required to make a diagnosis of CKD but the results of a biopsy may show a cause for the CKD. A biopsy is more likely to show specific information when the kidneys are big rather than small. A biopsy can be valuable in pets who develop CKD at a young age or who are of a breed known to develop congenital kidney disease. There may be specific microscopic changes in a kidney biopsy from an animal with congenital kidney disease that may suggest that related animals are also at risk for developing CKD. Knowledge that the cause of CKD is caused by congenital kidney disease does not change the treatment of the affected animal but does provide information for related animals, for example if you should remove them from a breeding program. When a biopsy is planned, usually the biopsy is collected using ultrasound or laparoscopy to see the kidney during the biopsy so that no other organs are damaged during the biopsy.
3. Bacterial culture
   What might this test show?  Bacterial infection is not a common cause of CRD but pets with CKD may develop a bacterial infection as several aspects of the pet's immune system may be less functional when the kidneys are failing.  If white blood cells are observed on microscopic examination of the pet's urine, a bacterial culture of the urine should be obtained.
4. Tests of clotting ability
   What might this test show?  If a pet is going to under go kidney biopsy, tests may be performed in advance to evaluate the ability to stop the bleeding from the biopsy site.

Treatment of CRF

The severity of the pet's signs will determine what treatments are needed. Not all treatments presented below may be needed or appropriate for each pet with a diagnosis of CKD. Treatments may also be started incrementally (a few treatments are started and then based on patient response, additional treatments may be added later). The information below is not meant to be a substitute for veterinary care.

Pets with severe signs may be hospitalized for fluid and intravenous drug treatment to reduce the amount of waste products in their body. Many pets with CKD will feel better in response to treatment with IV fluids but if the kidney disease is extremely severe the pet may not respond to treatment.

Those pets who are still eating and not showing severe signs are treated with a variety of treatments, often introducing treatments incrementally as new signs develop. The treatment approach is often called "conservative" compared to more aggressive treatments such as hospitalization for fluid therapy, dialysis or kidney transplantation. Remember that CKD is not a disease that can be cured. Treatments are designed to reduce the work the kidneys need to perform, to replace substances that may be too low (such as potassium) and to reduce wastes that accumulate such as urea (generated by the body from proteins) and phosphorus. The initial response to conservative therapy may be relatively slow, taking weeks to months to see a response.

Diet
Feeding of a kidney diet is usually recommended. Kidney diets contain less protein compared to other diets and the protein is high in quality. It is protein in the diet that is converted to waste products that the kidneys must remove in the urine. The higher the quality of the protein in the diet, the less wastes created for the kidneys to eliminate. Low quality protein requires the kidneys remove more wastes. which makes them work harder. Egg and meat contain higher quality protein; cereal grain protein is of lower quality which leads to more wastes for the kidneys to eliminate. Protein is used by the body to repair cells and tissues that are continually regenerating, so a pet needs some protein in their diet. By feeding a low quantity, but high quality protein diet that contains an appropriate amount of fats and carbohydrates, the pet's body can use the protein for replacing the cells and tissues and use the fat and carbohydrates for energy. Kidney diets also contain a lower amount of phosphorus. Phosphorus accumulates in the blood when the kidneys are diseased. Kidney diets control the amount of other substances that may be too high or too low in patients with CKD such as salt, potassium, magnesium and B vitamins. There are differences in the kidney diets for dogs and cats. When making diet changes it is often beneficial to gradually introduce the new diet by adding increasing amounts of the new diet while reducing the amount of the current diet over 1 to 2 weeks. The pet is more likely to accept a new diet when it is introduced gradually and it is less stressful to the kidneys to gradually adapt to changes in the diet.

Protein restricted diets are less palatable than higher protein diets. Pets with CKD that are still eating are more likely to accept a change in diet to a protein restricted diet than are pets who are very ill and refusing most foods. Protein restricted diets are more expensive than higher protein diets.

There are many pet food companies that sell kidney diets.  Dr. Tony Buffington at the Ohio State University is a good source of information on available diets. http://vet.osu.edu/1442.htm  select a species, a diet form and select Reduced Phosphorous/Protein for a list of diets for pets with kidney disease. Homemade diets can be fed but it is best to work with your veterinarian to formulate a diet that is balanced.

Water
Because pets with kidney disease cannot conserve water by making concentrated urine, their water intake is very important to prevent dehydration. Make sure they always have plenty of fresh water available.  If the pet is not eating well, or is vomiting, then s(he) may not be drinking enough and may get dehydrated. Pets can be encouraged to drink by giving them flavored broths in addition to plain water. The broth should be low in sodium and its best to discuss with your veterinarian other ingredients in the broth to make sure it doesn't contain substances that will make the kidneys work harder.

Water soluble vitamins like B and C are lost in greater amounts when the pet is urinating greater amounts. Kidney diets contain increased amounts of water soluble vitamins so additional vitamins do not need to be given unless a homemade diet is being fed.

Potassium
Lack of appetite and increased loss of potassium in urine may result in low body potassium (hypokalemia).  Cats with CKD are more likely to have low body potassium than are dogs. Cats with low potassium may develop painful muscles. Both cats and dogs may be weak when potassium is low. Cat kidney diets contain higher levels of potassium so additional supplementation is probably not needed unless the cat shows signs of muscle pain.  Potassium gluconate or citrate can be given by  mouth if potassium supplementation is needed. Potassium chloride is acidifying and is not recommended.

Phosphorus, calcium and PTH
Pets with CKD usually have increased blood phosphorus. In health, phosphorus and calcium are controlled by a hormone called parathyroid hormone (PTH). PTH works with vitamin D on the intestine, kidney and bone to keep calcium and phosphorus normal.  As the kidneys fail the amount of PTH in the body is elevated and the amount of vitamin D is reduced. Elevated PTH itself may be responsible for some of the signs shown by pets with CKD.  PTH draws calcium and phosphorus from the bones which can weaken bones which can lead to bone fracture.

Kidney diets typically contain reduced phosphorus and an appropriate amount of calcium but if phosphorus remains elevated when the pet is eating a kidney diet then phosphorus can be tied up in the intestinal tract so it can be eliminated in the stool. Intestinal phosphate binding agents include aluminum carbonate, aluminum hydroxide, aluminum oxide, calcium citrate, calcium acetate and calcium carbonate and sevelamer hydrochloride.  Phosphate binding agents which contain calcium should not be used until blood phosphorus is normal to prevent calcium and phosphorus from combining and precipitating in tissues including the kidneys. It is not usually necessary to give additional calcium but if a pet has low blood calcium, the phosphorus should be normalized before giving calcium.  Even when blood phosphorus is normalized, PTH levels are still higher than normal. The administration of low doses of vitamin D (1, 25 dihydroxycholecalciferol [calcitriol]) will suppress PTH and possibly  slow the rate of progression of kidney deterioration.

It is not 100% agreed that giving your pet calcitriol will slow the deterioration of the kidneys.

Here are some web sites on using calcitriol http://members.bellatlantic.net/~vze2r6qt/calcitriol/

Acidosis
Some pets with CKD will have an acid blood pH.  Kidney diets are designed to counteract the acidosis but very sick animals that are hospitalized may need addition treatment to correct the acidosis.

Sodium
Diseased kidneys are less efficient at regulating sodium and sodium in turn helps control blood volume and pressure. Excess sodium can lead to water retention and not enough sodium can lead to dehydration. When changing diets that contain different amounts of sodium (kidney diets usually have less sodium than regular diets) make the change  gradually over several weeks. Use caution when giving your pet table scraps or treats that may be high in sodium.

High blood pressure (hypertension)
Many pets with CKD have high blood pressure. High blood pressure can contribute to further decline of kidney function and can occasionally lead to sudden blindness from retinal detachment. Ideally blood pressure should be measured by your veterinarian and hypertension confirmed before giving drugs to treat high blood pressure but measuring true blood pressure in dogs and cats can be difficult.  If the pet has an elevation in blood pressure it may be due to the excitement of being examined or due to CKD. The calmer you are able to keep your pet during examination, the more reliable the readings for blood pressure. There are several drugs that may be used to manage high blood pressure including enalapril, benazepril, or amlodipine (and others).  Enalapril and benazepril are in a class of drugs called <align="left"> ACE inhibitors and are sometimes used in pets with CKD that have abnormal amounts of protein in their urine even when blood pressure is normal.

Anemia
The kidneys play a role in producing a hormone called erythropoietin which stimulates the production of new red blood cells. Red blood cells live about a hundred days so new cells are continually being made. Less erythropoietin is made in pets with CKD leading to anemia.  The packed cell volume (PVC) (also called hematocrit) is the percentage of blood cells compared to fluid in whole blood. When the PCV is ~20 in cats and ~ 25% in dogs, anemia may contribute to lack of activity and weakness.

Anemia can be treated by blood transfusion or by the administration of human erythropoietin. Erythropoietin is very effective in increasing PCV but because human erythropoietin is not exactly the same as dog and cat erythropoietin, over time, the pet may form antibodies that cause the medication to become ineffective. Canine and feline erythropoietin are currently being studied.

Fats/lipids
Certain types of fats (polyunsaturated omega 6 fatty acids) may slow the decline in kidney function are are often present in kidney diets.

Subcutaneous Fluids
Some cats and dogs with kidney disease may not drink enough to prevent becoming dehydrated and may benefit from the administration of intermittent SC fluids. If your veterinarian feels your pet may benefit from giving subcutaneous fluids, we provide some instructions on how to give SC fluids.  See Cat Fluids or Dog Fluids

Lack of Appetite
The accumulation of wastes in the body often decreases appetite. A goal of several of the above treatments is to reduce the amount of wastes in the blood. If the pet remains off food despite above treatments you might try different brands of renal failure diets, warming the food or adding odiferous toppings to entice the pet to eat.

Vomiting
Increased levels of waste products cause the pet to vomit. Your veterinarian may recommend medications that reduce nausea or act directly on brain centers to reduce the urge to vomit.

Drugs used to treat other diseases
Because the kidneys are responsible for elimination of many drugs, make sure that your veterinarian is aware of any other medications you are giving your pet as these may accumulate in the body to toxic levels if the kidneys cannot eliminate them.

Antibiotics
If the urine shows signs of infection or if a urine culture grows bacteria then antibiotics may be administered. If a urinary tract infection is involving the kidneys, the period of treatment is much longer than a infection of the bladder.

Avoiding Stress

You are in the best position to judge what is stressful to your pet. When a pet is stressed they may drink and eat less than normal. Reduced water intake is detrimental to diseased kidneys. When possible, keep your pet calm. That might mean for example: having an in-home pet sitter if your pet is stressed by boarding, removing the pet from the household during a party or limiting contact with other animals if these situations appear to be a source of stress for your pet. Extremes in heat or cold are stresses.  Certain drugs such as prednisone/cortisone make the kidneys work harder.

Certain conditions predispose a dog or cat to developing diabetes. Animals that are overweight or those with inflammation of the pancreas are predisposed to developing diabetes. Some drugs can interfere with insulin, leading to diabetes. Glucocorticoids, which are cortisone-type drugs, and hormones used for heat control are drugs that are most likely to cause diabetes.  These are commonly used drugs and only a small percentage of animals receiving these drugs develop diabetes after long term use.

The body needs insulin to use sugar, fat and protein from the diet for energy. Without insulin, sugar accumulates in the blood and spills into the urine.  Sugar in the urine causes the pet to pass large amounts of urine and to drink lots of water. Levels of  sugar in the brain control appetite. Without insulin, the brain becomes sugar deprived and the animal is constantly hungry, yet they may lose weight due to improper use of nutrients from the diet. Untreated diabetic pets are more likely to develop infections and commonly get bladder, kidney, or skin infections. Diabetic dogs, and rarely cats, can develop cataracts in the eyes. Cataracts are caused by the accumulation of water in the lens and can lead to blindness. Fat accumulates in the liver of animals with diabetes. Less common signs of diabetes are weakness or abnormal gait due to nerve or muscle dysfunction.  There are two major forms of diabetes in the dog and cat: 1) uncomplicated diabetes and 2) diabetes with ketoacidosis. Pets with uncomplicated diabetes may have the signs just described but are not extremely ill.  Diabetic pets with ketoacidosis are very ill and may be vomiting and depressed.

The diagnosis of diabetes is made by finding a large increase in blood sugar and a large amount of sugar in the urine. Animals, especially cats, stressed by having a blood sample drawn, can have a temporary increase in blood sugar, but there is no sugar in the urine.  A blood screen of other organs is obtained to look for changes in the liver, kidney and pancreas. A urine sample may be cultured to look for infection of the kidneys or bladder. Diabetic patients with ketoacidosis may have an elevation of waste products that are normally removed by the kidneys.

The treatment is different for patients with uncomplicated diabetes and those with ketoacidosis.  Ketoacidotic diabetics are treated with intravenous fluids and rapid acting insulin.  This treatment is continued until the pet is no longer vomiting and is eating, then the treatment is the same as for uncomplicated diabetes.

  Insulin comes from different sources including beef or pork pancreas and a human genetically engineered form called Humulin.  The availability of animal-source insulins continues to decline.

In general, cats and small dogs need insulin injections more frequently, usually twice daily, compared to large breed dogs that may only require one dose of insulin daily. The action of insulin varies in each individual and some large dogs will need 2 insulin shots daily.  The insulin needs of the individual animal are determined by collecting small amounts of blood for glucose (sugar) levels every 1-2 hours for 12-24 hours. This is called an insulin-glucose-response curve. When insulin treatment is first begun,  it is often  necessary to perform several insulin-glucose-response curves to determine:

• which insulin type to use
• how much insulin to give
• how often to give insulin
• when is the best time to feed the animal

The animal's insulin needs may change over time requiring a change in insulin type or frequency of injection. Insulin- glucose- response curves are usually performed several days after a change in insulin is made.

  Before you give insulin injections to your pet, your veterinarian will show you how to:

• handle insulin
• use a syringe
• draw insulin from the bottle in the correct amount
• give your pet the insulin shot

Insulin is fragile and will become less effective or even inactive, if it gets too hot or cold, or is shaken vigorously. Pay attention to the expiration date on the bottle. Discard insulin that is outdated.

You may be able to practice using water and giving the "shot" to an object such as a piece of fruit until you are comfortable using needles, syringes and drawing accurate amounts of fluid into a syringe. 

Insulin syringes can fill to hold:

• 30 units
• 50 units
• 100 units

Usually the skin is not cleansed before inserting the needle. If the cat has a normal immune system, the few bacteria that are pushed under the skin with the needle will be killed by the cat's immune system.

You can use alcohol on a cotton ball to make the hair lay flat so it is easier to see where the hair ends and the skin starts. Alcohol takes about 30 minutes before bacteria are killed, so just swiping the hair with alcohol is not effective in killing bacteria.

Give the insulin shots in different locations each time.

Syringes and needles used to give insulin should not be discarded in the trash but should be placed in a puncture-proof container and taken to your veterinarian for disposal. 

Insulin injections are not as perfect as the insulin produced by the pancreas. Blood sugar levels will not always be normal in diabetic pets. The goal of treatment is to reduce the  signs of diabetes. When diabetes is well controlled with insulin, the pet should drink, eat and urinate normal amounts.  They should have a good appetite, without becoming fat and should have normal activity. 

Insulin needs are closely related to the type of  food eaten by the pet. Your veterinarian will recommend a specific diet and feeding regimen that will enhance the effectiveness of insulin. If your pet is overweight, s(he) will be placed on a weight-reducing diet. As the pet loses weight, less insulin will be needed. Only feed the recommended diet..NO table scraps or treats that are not part of the recommended diet.

Heavy exercise will reduce the amount of insulin needed. It is important  to talk to your veterinarian before making changes in diet or exercise.

There is always some risk that a diabetic patient will develop low blood sugar. Signs of low blood sugar include weakness, staggering, seizures, or just being more quiet than usual. You should keep corn syrup on hand to rub on the animals gums if they have signs suggestive of low blood sugar.  Don't pour large amounts of corn syrup in the mouth of an animal that is not fully conscious as the syrup may be inhaled into the lungs.

Because insulin needs vary with the activity and lifestyle of your pet, you may want to keep a written daily log of:

• the dose of insulin
• location in which the insulin is injected
• any changes in the pet’s activity or appetite

Your veterinarian may ask you to check your pet's urine for sugar using a test strip. If your pet is well regulated on insulin, the sugar readings in most urine samples will be negative or trace. The strips may have color pads only for glucose or for glucose and ketones.

The strip is placed in fresh urine and the color change compared with the colors on the bottle. Be sure to follow the label instructions for timing when to read the results.  

You should never change the dose of insulin based on the urine sugar reading alone. Animals can have lots of sugar in their urine either when the insulin dose is too low or is too high.   

Diabetes is rarely reversible in dogs, but diabetic cats will sometimes regain the ability to produce their own insulin in the pancreas. Cats that developed diabetes after receiving long term glucocorticoids or hormones are more likely to stop needing insulin after a while compared to cats that developed diabetes without a known cause. 

You should have your diabetic pet evaluated by a veterinarian at 2-4 month intervals or anytime another health problem develops. The development of other health problems will often interfere with insulin regulation.

Small intestinal and large intestinal diarrhea have different causes, require different tests to diagnose and are treated differently.  Small intestinal diseases result in a larger amount of stool passed with a mild increase in frequency; about 3 to 5 bowel movements per day. The pet doesn't strain or have difficulty passing stool. Animals with small intestinal disease may also vomit and lose weight. Excess gas production is sometimes seen and you may hear the rumbling of gas in the belly. If there is blood in the stool it is digested and black in color.

Disease of  the large intestine including the colon and rectum cause the pet to pass small amounts of loose stool very often, usually more than 5 times daily. The pet strains to pass stool. If there is blood in the stool,  it is red in color. The stool may be slimy with mucus. The pet does not usually vomit or lose weight with large bowel diarrhea. A sudden onset of small intestinal diarrhea may be caused by viruses including canine distemper, canine parvovirus, canine coronavirus, feline panleukopenia virus or feline coronavirus, in young, poorly vaccinated pets. Small intestinal diarrhea can be caused by bacteria such as salmonella, clostridia or campylobacter although these same bacteria can be found in the stool of normal dogs and cats.

Worms and giardia can cause small intestinal diarrhea, mostly in young animals. Foreign bodies including bones, sticks and other objects can pass through the stomach and get stuck in the intestine causing both diarrhea and vomiting. These same foreign materials may pass through the intestinal tract without getting stuck but may damage the lining of the intestinal tract causing diarrhea. Dietary indiscretion or a sudden change in diet can cause diarrhea with or without vomiting.  Food allergies in dogs and cats can cause diarrhea, vomiting or itchy skin. Toxins including lead and insecticides can cause diarrhea usually with vomiting.  Inflammatory bowel disease (IBD) occurs commonly in both dogs and cats. In IBD the walls of the intestine contain abnormal numbers of inflammatory cells which can be eosinophils, lymphocytes or plasma cells.  The cause of IBD is not known but is suspected to be an allergic reaction to components of food, bacteria or parasites. IBD can be congenital in some breeds of dogs, for example Basenji dogs may develop a severe inflammatory bowel disease. Tumors of the intestine are another cause of diarrhea usually occurring in older pets. The tumor may be a single mass when the tumor is from the glands of the intestine (adenocarcinoma) and may be removed by surgery or the tumor may occur diffusely along the intestine. Lymphosarcoma occurs in both dogs and cats and can either be a single or multiple masses in the intestine or the abnormal lymphocytes may be spread through out the intestine. Lymphosarcoma is often responsive to anti-cancer drugs in cats but rarely responds to anti-cancer drugs in dogs.

In certain parts of the country small intestinal disease can be caused by fungal infections including histoplasmosis. Your veterinarian can discuss with you whether histoplasmosis is seen in your part of the country. Diseases outside the intestinal tract that may cause diarrhea include kidney failure, liver failure, pancreatic disease and hyperthyroidism in the cat. Severe inflammation of the pancreas (pancreatitis) can lead to damage of the pancreas and an inability to make enough enzymes to digest fat. This is called pancreatic insufficiency and causes diarrhea with a large volume of  greasy stool.  Pancreatic insufficiency can occur in young animals due to a congenital deficiency of pancreatic enzymes.

The cause of small intestinal diarrhea may be determined from blood tests, examination of the stool, x-rays or ultrasound of the abdomen or by endoscopy.  Endoscopy is the technique of passing a flexible scope through the stomach into the upper intestine. Small biopsies of the lining of the intestine can be taken for microscopic evaluation. Endoscopy requires general anesthesia. A diagnosis of intestinal lymphosarcoma may be missed on endoscopy as the biopsies taken using endoscopy do not include the full thickness of the wall of the intestine and the cancerous cells may be deep in the wall of the intestine. A diagnosis in that case requires surgery in order to take a larger biopsy of the entire thickness of the intestine.

Dogs and cats with chronic small intestinal diarrhea will lose weight as they are unable to properly absorb nutrients and may develop edema of the legs or fluid accumulation in the belly or chest. A small protein, albumin may be lost in diarrhea. Albumin acts like a sponge to keep water in the blood vessels. When albumin is lost in the stool, blood albumin gets low and water leaks out of blood vessels to accumulate in other locations. Chronic diarrhea may cause the fur to look dull and brittle due to nutrient deficiencies. Acute small intestinal diarrhea can be managed by withholding food, but not water for 24 - 48 hours. If diarrhea stops, small amounts of a bland low-fat food are fed 3 to 6 times daily for a few days, with a gradual increase in the amount fed and a gradual transition to the pet's normal diet. Foods designed as intestinal diets usually contain rice as rice is more digestible than other grains. You are discouraged from administering over-the-counter diarrhea medications without first consulting a veterinarian.  If the pet is active, not dehydrated and has been previously healthy, acute diarrhea can often be managed at home. Diarrhea that continues for more than a few days or is accompanied by depression or other signs is an indication to take your pet to a veterinarian.

Diarrhea of  large intestinal origin can be caused by whipworms, polyps, inflammatory bowel disease, colonic ulcers or colonic cancer. Stress can cause large bowel diarrhea in excitable dogs.  The diagnosis of large intestinal diarrhea is also made by blood tests and examination of the stool. A rectal examination using a gloved finger may provide some information about the cause of large bowel problems including rectal polyps and rectal cancer.  Endoscopy to examine the large intestine is performed using a rigid or flexible scope passed up the rectum. Because the rectum is often very irritated, colon exams are usually performed under general anesthesia.

The treatment of large bowel diarrhea may be based on a specific diagnosis. Non specific treatment of large bowel diarrhea often includes a high fiber diet and sullfasalazine, an anti-inflammatory drug.

Black Earth Veterinary Clinic assumes no liability for injury to you or your pet incurred by following these descriptions or procedures.

Some pets show no sign of illness, especially early in the disease. In other cases, signs of left-sided congestive heart failure (fluid accumulation in the lung) may occur. These signs include lethargy, decreased activity level, rapid and/or labored breathing and possibly open mouth breathing with excitement or exercise. Sometimes left and right-sided congestive heart failure develop with fluid accumulation inside the chest or abdominal cavity causing greater respiratory (breathing) effort and abdominal distention. Once fluid accumulations have occurred, clinical heart failure is present and aggressive medical therapy should be sought. Other signs of this disease can include sudden weakness, collapsing episodes, and unfortunately even sudden death due to disturbances in heart rhythm. In some cats with a very large heart chamber (i.e. left atrium) a blood clot may form and if it enters the circulation may cause weakness or paralysis (usually of the rear legs). If this occurs, contact your veterinarian right away to determine if complications related to heart disease (or another disease) are present.

A physical examination performed by your veterinarian may reveal a heart murmur, abnormal heart sounds, abnormal lung sounds, or irregularities in heart rhythm. Chest radiographs (x-rays), an electrocardiogram (ECG..sometimes called an EKG), and an echocardiogram (heart ultrasound) are tests often utilized to confirm a suspected diagnosis and to determine severity. A routine physical exam and one or more of these tests may be recommended every six months to one year to look for any progression of disease in cats without clinical signs.

Asymptomatic pets may not need medical therapy depending on the findings of the tests listed above, but routine reevaluations will often be recommended. Other cats will need medications to slow the heart rate, and promote relaxation of the pumping chambers (ventricles). If arrhythmias or congestive heart failure signs are present, additional medications used may be required. Since this disease can be progressive, the number and the amount of medications used may change with time. Therapy is always tailored to the needs of the individual patient. If congestive heart failure is present, dietary salt reduction is also recommended.

Medications commonly used for HCM:

Beta-adrenergic blockers such as atenolol (Tenormin) or propanolol (Inderal). These medications slow the heart rate, which enhances filling and relaxation of the pumping chambers. Beta-blockers also allow more time for blood flow to the heart muscle itself, and reduce the amount of oxygen used by the heart. In some cases, the incidence of arrhythmias is also lessened. Side effects may include bronchospasm (spasm of the airways) (propranolol), fatigue, and in excessive doses,  slow heart rate and low blood pressure.

Calcium-channel blockers such as diltiazem (Cardizem CD, Dilacor XR). This class of drug has similar actions to the beta-blockers. Some differing characteristics of the calcium-blockers include little or no anti-arrhythmic activity in some cases, possible a greater ventricular relaxing effect, and a greater propensity for low blood pressure at higher doses.

Other medications may be prescribed in some patients. Diuretics (furosemide, spironolactone, etc.) may be needed to control edema and effusions (congestive heart failure). In pets that have had or may be prone to blood clot formation, anti-coagulants such as aspirin, warfarin, or heparin may be prescribed.

Medical therapy is always chosen to meet the needs of the individual patient. Frequent recheck examinations and adjustments may be needed especially early in the course of treatment to individualize a medication regimen.

This Pet Health Topic was written by O. L. Nelson, DVM, MS, Diplomate ACVIM (Cardiology & Internal Medicine) Washington State University.

What are the signs of this disease?

Early in the disease process there may be no clinical sign detectable, or the pet may show reduced exercise tolerance. In some cases, a heart murmur (usually soft), other abnormal heart sounds, and/or irregular heart rhythm is detected by your veterinarian on physical examination. Such findings are more likely as the disease progresses.

As the heart’s pumping ability worsens, blood pressure starts to increase in the veins behind one or both sides of the heart. Lung (pulmonary) congestion and fluid accumulation (edema) often develop behind the left ventricle/atrium. Fluid also may accumulate in the abdomen (ascites) or around the lungs (pleural effusion) if the right side of the heart is also diseased. When congestion, edema and/or effusions occur, heart failure is present. Weakness, fainting episodes, and unfortunately, even sudden death can result from heart rhythm disturbances (even without "heart failure" signs).

What are the signs of heart failure?

Dogs with heart failure caused by DCM often show signs of left-sided congestive failure. These include reduced exercise ability and tiring quickly, increased breathing rate or effort for the level of their activity excess panting, and cough (especially with activity). Sometimes the cough seems soft, like the dog is clearing its throat. Poor heart pumping ability and arrhythmias can cause episodes of sudden weakness, fainting, or sudden death as noted above. Some dogs with DCM experience abdominal enlargement or heavy breathing because of fluid accumulation in the abdomen or chest, respectively. Presence of any of these signs should prompt a visit to your veterinarian to determine if heart failure (or another disease) has developed.

More advanced signs of heart failure could include labored breathing, reluctance to lie down, inability to rest comfortably, worsened cough, reduced activity, loss of appetite, and collapse. A veterinarian should be consulted right away if these signs occur. Signs of severe heart failure may seem to develop quickly with DCM, but the development of underlying heart muscle abnormalities and progression to overt heart failure probably takes months to years.

How is this disease diagnosed?

A cardiac exam by a veterinarian can detect abnormal heart sounds (when present) and many signs of heart failure. Usually chest radiographs (x-rays), an electrocardiogram (ECG), and echocardiogram are performed to confirm a suspected diagnosis and to assess severity. Echocardiography also can be used to screen for early DCM in breeds with a higher incidence of the disease. Resting and 24-hour (Holter) ECGs are sometimes used as screening tests for the frequent arrhythmias that usually accompany DCM in some breeds, especially boxers and Doberman pinchers.

What can be done if my pet has this disease?

Asymptomatic (subclinical) cases of DCM may be treated with enalapril or another ACE inhibitor to slow progression of the changes leading to heart failure. Other medications and strategies are also used as signs of heart failure develop and/or if rhythm abnormalities are present. Therapy is always tailored to the needs of the individual patient. Since this disease is not reversible and heart failure tends to be progressive, the intensity of therapy (for example, the number of medicines and the dosages used) usually must be increase over time.

This Pet Health Topic was written by O. L. Nelson, DVM, MS, Diplomate ACVIM (Cardiology & Internal Medicine) Washington State University.

Certain breeds have an inherited predisposition to this disease. Degenerative valvular disease is slowly progressive over years and is non-reversible. The volume of blood that leaks back into the atrium with each heartbeat tends to increase slowly over time. However, many dogs with this disease never develop signs of congestive heart failure even though they may have a loud murmur. Early in the disease process, your veterinarian may hear a soft murmur when the affected valve starts to leak. There usually is no noticeable change in the dog’s activity level or behavior for a long period of time. Gradually, though, the valve leak tends to get worse and the heart slowly enlarges. If the leak becomes severe, blood may start to back up behind the heart – usually into the lungs. This causes lung congestion and fluid accumulation (edema). When lung congestion and edema occur, congestive heart failure is present.

Reduced exercise ability may be the first sign of heart failure. Most dogs with heart failure caused by degenerative valve disease show signs of "left-sided" congestive failure. These signs include tiring quickly, increased breathing rate or effort for the level of activity, excessive panting, and cough (especially with activity). The presence of any of these signs should prompt a visit to your veterinarian to determine if heart failure (or another disease) has developed. 

More advanced signs of heart failure could include labored breathing, reluctance to lie down, inability to rest comfortably, worsened cough, reduced activity, and loss of appetite. Your veterinarian should be consulted right away if these signs occur.

Some dogs that become symptomatic from their heart disease develop fluid in the abdomen (ascites); others have episodes of sudden weakness or fainting that can result from irregular heartbeats or other complications. As long as no sign of heart failure develops, no treatment is necessary, although reduction of dietary salt intake is often advised. Again, there are many dogs with degenerative valvular disease that never progress to heart failure. 

However, if heart failure develops, several medications and other strategies are used to control the signs. Since the disease is not reversible and heart failure, when it occurs, tends to be progressive, the intensity of the therapy (including the number of medicines and dosages used) usually must be increased over time. 

Therapy is always tailored to the needs of the individual patient.

This Pet Health Topic was written by O. L. Nelson, DVM, MS, Diplomate ACVIM (Cardiology & Internal Medicine) Washington State University.

Tinsel, Ribbon and other Pretty Things

Ribbons, wrapping paper, ornaments, tinsel, extension cords and gifts may be appealing "chew toys" that may make your pet sick.

There is something about those shiny strands of Christmas tree decor, which drives kitties wild. Although the sight of your cat pawing at the tree may be cute, the ingestion of tinsel can be deadly. Eating tinsel or other string-like items such as ribbon (often called linear foreign bodies)  can cause serious damage to the intestine. One end can get stuck while the rest is pulled into the intestine as it contracts; the contractions may cause the ribbon or tinsel to saw through the intestine. If not caught in time, infection of the belly cavity develops and the prognosis for recovery becomes poor. Pets with linear foreign bodies quickly become ill with signs including vomiting, diarrhea, depression, belly pain and sometimes fever.

Eating other holiday decorations can cause signs ranging from mild depression to severe vomiting or diarrhea, depending upon whether or not the foreign matter can be passed in the stool or gets stuck along the way. Foreign matter stuck in the intestine often does NOT show up on "x-ray" but sometimes the foreign matter will trap air in the intestine, which helps your veterinarian make a diagnosis. Surgery is required to remove foreign matter that does not pass out on its own.

Holiday Lights

Decorative lights are another attraction for pets to chew on. Both indoor and outdoor lights should be carefully examined to ensure safety for your household pets. Electrical shock may occur from defective cords as well as from pets chewing on cords. Check cords for any signs of bite marks, loose or frayed wires, proximity to the tree's water supply or evidence of short circuits. Use grounded "3-prong" extension cords and strictly follow manufacturer's guidelines for light usage.

Electrical shock can cause burns, difficulty breathing, abnormal heart rhythm, loss of consciousness, and death. Call a veterinarian immediately if your pet has been injured by electrical shock. Treatment will be most effective if begun soon after the shock.

Water, Water...

Even though they have their own water bowel, there is something enticing about a novel source of water; whether it's the toilet bowl or the Christmas tree stand. If you add chemicals to the water meant to keep your tree fresh longer, be sure to read the label to make sure it is safe for pets.

Potpourri makes your house smell festive but may be another attraction for pets to drink. Make sure that potpourri pots are covered or otherwise inaccessible to pets.

It may be difficult to curb your pet's fascination with all those pretty decorations. Child gates can be used across doorways to keep your pet away from the Christmas tree and decorations at times they cannot be watched.

Overindulgence

Well-intentioned family and friends may share holiday foods with pets causing the pet to develop a stomach upset or worse, pancreatitis (inflammation of the pancreas) which can be caused by eating fatty foods. To control excessive food intake by your pets and meet your guests' desires to feed the pets, dole out the treats your pets would normally receive and let your guests "treat" the pets. If you want to get festive, mix some of your pet's regular food with water to make a "dough" and roll out and cut into festive shapes, then bake until crunchy.

Extra attention from visiting relatives and friends may be relished by some pets while others seek solitude in their favorite hiding spot. Make sure pets are given some "personal space" if they want to get away from the commotion.

Some pets may respond to all the hullabaloo with a change in behavior including bad behaviors like eliminating in the house. Try to spend a little extra "quality time" with your pet to assure them they have not been forgotten.

Chocolate

What would the holidays be without boxes of chocolate and warm cocoa in front of the fire? However, chocolate can be toxic or even fatal to dogs and cats. Chocolate may be mistakenly given to pets as treats and may be irresistible to the curious canine. Chocolate poisoning occurs most frequently in dogs but other species are also susceptible. Theobromine is the toxic compound found in chocolate. Signs which may appear within 1 to 4 hours of eating chocolate include:

• Vomiting 
• Increased thirst 
• Diarrhea
• Weakness
• Difficulty keeping balance
• Hyperexcitability
• Muscle spasms, seizures, coma
• Death from abnormal heart rhythm

The toxicity of chocolate depends on the amount and type of chocolate ingested:

The amount of theobromine in white chocolate or chocolate flavored dog treats is usually negligible. As with any poisoning, call your veterinarian or an emergency veterinary hospital immediately if you suspect your pet may have ingested chocolate. Have the product label information available when you call your veterinarian. There are national and regional poison control hotlines for animals. In general, the treatment of poisonings is most effective if begun soon after eating the poison, before large amounts are absorbed into the blood.

Poinsettias & Mistletoe

Poinsettias fill homes with color during the holidays. Poinsettias have received bad publicity in the past whereas in fact, poinsettias are not very toxic to pets. They do contain a milky sap that can irritate the mouth but if signs develop they are usually mild.

Mistletoe can be very toxic to animals and you should seek veterinary consultation immediately if your pet has potentially ingested any part of the plant. Mistletoe can cause vomiting, severe diarrhea, difficult breathing, shock and death within hours of ingestion.

There are many species of Holly (genus Ilex) Berries and leaves can be a problem although signs of poisonings are generally mild, and include vomiting, belly pain, and diarrhea.

  Pets as Gifts

A cute, cuddly puppy or kitten may seem to be the perfect gift but unfortunately after the holiday season the population of animal shelters explodes with these "surprise gifts". Owning a pet is a long-term commitment that not every one can make. 

Dealing With Death or Severe Illness over the Holidays

The holiday season heightens our emotions and can be a very difficult time to deal with the loss or illness of a companion animal. The bond between animals and humans is often very strong and losses can be very painful. If you or someone you know needs support without judgment from those who appreciate your feelings and may be able to help, please contact the WSU College of Veterinary Medicine Pet Loss Hotline.

From all of us at the College of Veterinary Medicine at WSU, best wishes for a safe and happy holiday season for you and your pets.

Other Holiday & Seasonal Tips:

Cold Weather Pet Tips

Gifts for the Pet Owner and other Holiday Tips

Prevention of Antifreeze Poisoning

This Pet Health Topic was written by Paul Chauvin, Washington State University, Class of 2004.

Signs of hyperthyroidism can include:     

• weight loss
• increased appetite
• increased activity and restlessness
• aggressive or "cranky" behavior
• a poor hair coat
• a fast heart rate
• increased water drinking 
• increased urination
• periodic vomiting
• increased amount of stool or diarrhea
• occasionally difficulty breathing 
• occasionally weakness
• occasionally depression

A diagnosis of hyperthyroidism is made when the level of thyroid hormone is increased in the blood.  Most hyperthyroid cats have very high levels of hormone but some cats will have signs of hyperthyroidism with normal or only slightly increased levels of thyroid hormone.  Thyroid hormone levels can vary over time so it may be necessary to check blood levels several times or perform a different test called a T3 suppression test. The enlarged thyroid gland(s) can often be felt in the neck. If the diagnosis is not obvious by blood tests, a nuclear medicine scan of the thyroid glands can be performed at certain specialty veterinary practices. The cat is given a small dose of a radioactive compound that travels by the blood to the thyroid glands. Hyperactive thyroid glands accumulate more of the compound than normal glands. After this test the cat must be hospitalized for a few days while it clears the radioactive compound from its body. 

A nuclear medicine scan of the thyroid glands. Both thyroid glands are abnormal in this cat and take up the radioactive compound. The other black spot is the stomach lining which will also take up the compound.

A blood panel and urinalysis are also performed to screen for abnormalities in other organs such as liver and kidney that may be present due to the advanced age of the animal. 

High levels of  thyroid hormone may cause heart disease. The heart may appear enlarged on x-ray or ultrasound and may show abnormal electrical activity on an ECG (electrocardiogram).  Heart disease may cause fluid to build up in or around the lungs. Cats with serious heart disease and hyperthyroidism need to be treated for both diseases. The heart disease will reverse in many cats after successful treatment of hyperthyroidism.  There are three types of  treatment for hyperthyroidism: 

• life long oral anti-thyroid  medications
• surgical removal of affected thyroid glands
• treatment with radioactive iodine

All three treatments will reduce thyroid hormone levels and the signs of hyperthyroidism. Discuss the 3 options with your veterinarian. If your pet has other diseases, one treatment may be better for your cat than another. 

The anti-thyroid pill is methimazole, also known as Tapazole. Methimazole is given one to three times daily and must be continued life long. It takes several weeks for methimazole to reduce blood thyroid hormone levels to normal. If methimazole is discontinued, thyroid hormone levels will return to high levels over a few weeks. Methimazole may be used to reduce thyroid hormone levels to normal before surgically removing the thyroid gland(s). Cats with heart disease may be too sick and fragile to anesthetize for surgery in which case methimazole can be given until the heart improves and the cat is stronger. Some owners (and their cats) find it difficult to give pills daily and may decide, after starting anti-thyroid pills, to later have their cat treated with radioactive iodine or surgery. Methimazole may produce side effects in cats including depression, vomiting and lack of appetite. These signs usually resolve without stopping the medication. A more serious side effect is the development of low blood cell counts which are more likely to develop during the first 3 months of treatment.  Blood cell counts should be evaluated every 2 weeks during the first 3 months. If blood cell counts decrease methimazole is stopped and another treatment method should be considered.  Enlarged thyroid glands can be surgically removed. Methimazole  is given for 1 to 2 months before surgery so that thyroid hormone levels are normal at the time of surgery. If both glands are enlarged, they can both be removed and most cats will still produce enough thyroid hormone by a few thyroid cells scattered through out the body to prevent hypothyroidism (abnormally low thyroid hormone levels).  A few cats will become hypothyroid and may need to take thyroid pills. Surgical removal of the thyroid gland(s) can usually be performed without complications. Occasionally complications may develop including damage to the parathyroid glands, which are closely attached to the thyroid gland, damage to nerves close to the thyroid gland or damage to the voice box. Parathyroid gland damage causes low blood calcium that may cause seizures.  Low blood calcium is treated with calcium or vitamin D.  Nerve damage causes abnormal size of the pupils of the eyes and droopy eyelids. Damage to the voice box causes a change in voice.

Some cats will remain hyperthyroid after surgical removal of the thyroid glands. These cats have thyroid cells in abnormal locations, including  inside the chest cavity where surgical removal is difficult. This extra thyroid tissue is called ectopic thyroid. If you and your veterinarian decide that surgery is the best treatment option for your cat, a nuclear medicine scan (described in the diagnosis section) could be performed at a specialty veterinary practice before surgery to see if your cat has ectopic thyroid tissue. If ectopic thyroid tissue is seen on the nuclear medicine scan, then a different treatment, either methimazole or radioactive thyroid treatment should be selected.  Cats that have had surgery may have recurrence of hyperthyroidism.  Blood thyroid hormone levels should be measured once or twice a year. Treatment with radioactive iodine is only performed at selected specialty veterinary practices. Radioactive iodine is given intravenously and will accumulate in the abnormal thyroid tissue killing the abnormal thyroid cells but sparing the normal thyroid cells.  Radioactive iodine will also accumulate in ectopic thyroid tissue. Radioactive iodine treatment is very effective and rarely causes hypothyroidism.  The cats do not have to be placed under anesthesia for the procedure. The disadvantages of radioactive iodine treatment include the need to travel to a facility that offers this treatment and the need for the cat to remain hospitalized until the level of radioactivity decreases to a safe level as determined by the state radiation control office (usually 1 to 3 weeks).

Radioactive iodine treatment of hyperthyroid cats is available at Washington State University.

Older cats with hyperthyroidism often also have kidney disease.  Treatment of these cats is a delicate balancing act.  Hyperthyroidism can actually improve kidney function by increasing blood flow to the kidneys. Some cats with kidney disease will show a worsening of kidney function after treatment for hyperthyroidism. Talk to your veterinarian about monitoring kidney function in hyperthyroid cats.

The most common signs of low thyroid function in dogs include loss or thinning of the fur, dull hair coat, excess shedding or scaling, weight gain, reduced activity and reduced ability to tolerate the cold. The hair loss occurs primarily over the body, sparing the head and legs, and is usually not accompanied by itching or redness of the skin. Some dogs will have thickening of the skin and increased skin pigment, especially in areas of friction, such as the armpit (axilla). Hypothyroid dogs often have ear infections and show ear pain, redness, and odor. Hypothyroid dogs may also develop skin infections which may be itchy and result in sores on the body. The accumulation of substances called mucopolysaccharides can cause the muscles of the face to droop giving the dog a facial expression that is sometimes called “tragic”.

Less commonly recognized signs that may be seen in a small number of dogs with hypothyroidism include dilation of the esophagus (megaesophagus) causing regurgitation, and abnormal function of nerves or muscles leading to weakness or abnormal ability to walk.

Routine blood tests can be affected by hypothyroidism, although the changes are not consistent and can be subtle. Dogs may have a mild anemia and increased levels of cholesterol.

There are several blood tests that can be used to confirm a suspected diagnosis of hypothyroidism. Blood testing for hypothyroidism is often performed as a panel of several tests in order to increase the yield of these tests. The results of some of these tests can be influenced by the presence of other non-thyroid diseases, so test results must be considered in light of the whole picture.

Treatment of hypothyroidism is by giving oral replacement hormone for the rest of the dog’s life. Initially thyroid hormone is usually given twice daily. Once the hair coat begins to improve, some dogs can be maintained on once daily medication. There are two general forms of thyroid medication, T3 and T4. T4 is converted to T3 by the body. Most hypothyroid dogs given T4 will convert it to T3 so almost all hypothyroid dogs receive T4 (levothyroxine or L-thyroxine). A few dogs are unable to make this conversion and require T3 medication.

It usually takes 4 to 6 weeks before regrowth of the fur is apparent. In dogs with associated ear infection, the ears should be cleaned and treated with antibiotics either in the ear or by mouth. Blood levels of the T4 are often measured in order to fine tune the dose.

Incontinence can also be confused with submissive urination. Submissive urination occurs when a dog is acting submissive to a person or to another dog. Submissive urination occurs more frequently in young animals. The dog usually rolls on its back and urinates. These dogs can also urinate normally.

Young animals may have a birth defect causing incontinence. The most common birth defect that causes incontinence in young dogs is ectopic ureter(s). The ureters carry urine from the kidneys to the bladder. If one or both ureters by-pass the bladder and connect to an abnormal location such as the urethra or vagina, the puppy may drip urine. Siberian Huskies are most often affected. Other breeds that have a higher occurrence of this birth defect include:

• Miniature Poodle
• Labrador Retriever
• Collie
• Welsh Corgi
• Wire-haired Fox Terrier
• West Highland White Terrier

Female dogs are more commonly affected. If only one ureter is abnormal the dog will dribble urine but can also urinate normally. If both ureters are affected then the puppy will only dribble urine and cannot pass urine normally.

To diagnose this condition a dye study of the bladder is usually performed. Sometimes the abnormal opening into the vagina can be seen during a careful examination under anesthesia using special equipment. 

Most puppies with ectopic ureter(s) also have a bladder infection that will improve with antibiotics but the infection will return until the problem is corrected.

In some cases the ureter can be surgically moved back to the normal location in the bladder and incontinence may resolve. In other cases, long standing infection of the kidney may have damaged the kidney requiring the removal of one kidney. In yet other cases the abnormality of the ureter can be corrected but the pet remains incontinent, probably due to the presence of other birth defects in the urinary system. 

A bladder infection can cause either a strong urge to urinate or if the bladder infection is long standing it can cause scarring of the bladder preventing it from stretching to hold urine. In this case the pet is usually not truly incontinent in that they know they are urinating, but they have such a strong urge to empty their bladder that they may urinate in abnormal locations or urinate very frequently. It is common to evaluate incontinent pets for the presence of a bladder infection. 

Pets with a partial blockage of the urethra with a stone or a tumor may show incontinence. If they cannot empty their bladder completely because something is blocking the path to the outside, the bladder may get so large that the back pressure of urine in the bladder actually forces some urine to leak around the blockage. In these pets the enlarged bladder can be felt on examination. Total blockage of urine flow is usually fatal in 3 to 4 days.

Hormone-responsive incontinence occurs in neutered dogs of both sexes and occasionally in spayed female cats but occurs most commonly in female dogs. The pet can urinate normally, but they leak urine while resting. Physical examination and blood and urine tests are usually normal in these pets. Hormone-responsive incontinence can occur months to years after a pet is neutered. 

As pets age they may become incontinent. This may be due to a weakening of the muscles that hold urine in the bladder. There are many diseases that can cause a pet to create more urine than normal (polyuria) and several of these occur in older pets. If a pet has one of these diseases and often has a full bladder, the full bladder can push against the weakened sphincter and cause incontinence. Older pets can also develop senility and simply be unaware that they are dribbling urine.

Dogs and cats with brain or spinal cord disease may either dribble urine or be unable to pass urine. Most often they will have other signs of nervous system disease such as muscle weakness or paralysis.

Intermittent incontinence, primarily at rest, has been reported in cats of both sexes that are positive for the feline leukemia virus. How the virus causes incontinence is unknown.

A less common cause of incontinence in female dogs is called vulvovaginal stenosis. It is a condition in which the vagina at the level where the urethra ends is narrowed. Occasionally when the pet urinates, some urine will get trapped in the vagina in front of this narrowed area. Then when they rise after lying down the urine pours out. This condition can be diagnosed by feeling the vagina with a gloved finger. In some dogs the narrowing can be stretched under anesthesia. The incontinence may or may not resolve as sometimes other defects are also present.

Diagnosis of incontinence

The tests performed to evaluate a pet with incontinence depend upon the age of the pet and on the presence or absence of other signs. It is common to collect a urine sample for bacterial culture and to see if the urine is dilute or shows evidence of an infection. Infections of the urine may be secondary to another cause of incontinence.

Questions that your veterinarian will ask to help identify the cause of your pet’s problem include: 

• The age when incontinence first appeared 
• When the incontinence is usually observed, for example at rest or with activity
• Whether the pet can urinate normally 
• Previous surgeries (such as neutering) and illness 
• Use of medications that might cause the urine to be dilute such as diuretics, anticonvulsants or prednisone 
• How much water the pet drinks
• How frequently the pet urinates and whether the pet seems to be uncomfortable when he or she urinates
• Whether the pet shows any signs of nervous system disease such as weakness or seizures

Blood tests may be performed to look for evidence of kidney damage from infection or for the presence of diseases that might lead to increased urine production. 

Plain and/or dye X-rays or ultrasound may be performed to look at the parts of the urinary tract. 

Treating the incontinent patient

Specific treatment of an underlying disease may resolve incontinence; for example, surgery to correct an ectopic ureter. Inappropriate urination caused by behavioral problems may be corrected with training that modifies the pet’s behavior.

When no specific cause can be identified for the incontinence drugs may be given that increase the tone of the muscles that hold urine in the bladder. Some drugs that are used for this purpose include estrogen, ephedrine and phenylpropanolamine. 

Drug therapy for incontinence may be based on “trial” of different drugs in various doses. Since some of these drugs can have side effects so low doses are tried first. Some drugs may be slow to have an effect so as long as there are no undesirable side effects, a drug trial should continue for several weeks before the drug is considered not to be effective.

Type I IVDD can occur in any area of the spinal cord. Dachshunds and other chondrodystrophic dogs (dogs with short legs and longer bodies) appear predisposed, as their disks age or degenerate more readily than most dogs. Young to middle-aged dogs are most commonly affected. Dogs less than 1 year of age rarely have intervertebral disc disease. Middle-aged to older large breed dogs can also develop disk disease (usually type II IVDD). Disc disease, in general, is rare in cats.

Signs of spinal cord disease (anything from back pain, to weakness in the limbs to paralysis of the limbs) develop due to the force of the disk material hitting the spinal cord, or because of the amount of disk material that enters the spinal canal and compresses the spinal cord. The more spinal cord damage, the more severe the clinical signs. The most important determinant of prognosis in a dog with IVDD is the ability to consciously feel their limbs. If a patient can still feel his limbs, even if he can no longer move his legs, there is an 80-85% that, if surgery is performed, he will have a functional recovery and be able to walk again.

IVDD is suspected as a diagnosis based on physical and neurologic exam findings, breed and history. To definitively diagnose IVDD, spinal x-rays, and either a CT scan or MRI of the spine are performed. Anesthesia is required to perform the latter two diagnostic procedures. Following advanced imaging, and the diagnosis of IVDD, surgery is then, sometimes, pursued. . General guidelines have been established for therapy depending upon severity of clinical signs. Mildly affected animals (animals back pain alone or those with mild weakness who are able to strongly walk) may be managed medically. Medical management entails strict cage confinement and appropriate pain medications for a total of 6-8 weeks. Confinement is very important to allow for healing of a degenerative disk. If, despite appropriate medical management a patient’s back pain is refractory or if the patient’s neurologic status worsens, surgery is pursued. Surgery is usually recommended in cases where animals are more severely affected (those who are unable to stand and walk). The goal of surgery is the removal of the extruded (type I IVDD) or protruded (type II IVDD).and subsequent relief of spinal cord compression.

This information was made possible by funds from the Neurology Endowment at Washington State University.

Structure of the kidneys

The microscopic unit of the kidney is called the nephron. Each kidney contains thousands of nephrons. When the pet is young and healthy not all nephrons are working all of the time; some nephrons are held in reserve. As the animal ages or if the kidneys are damaged, some nephrons die and other resting nephrons take over the work of those that die. Eventually all the remaining nephrons are working. When there are no extra nephrons remaining and kidney damage continues the pet will start showing signs of CKD. Because of this stepwise loss of nephrons the kidneys are able to "hide" the fact that they are damaged until the damage is severe. When 2/3 of the nephrons have been lost the pet is no longer able to conserve water and the pet passes larger amounts of dilute urine. By the time a pet has an elevation in the waste product creatinine in its blood, 75% of the nephrons in both kidneys have been lost.

What do the kidneys do?

When blood flows through the kidneys, the kidneys act as a complex filter that removes from blood wastes that are generated from break down of food, old cells, toxins or poisons and many drugs that are given for treatment of other diseases. The wastes are removed with water as urine. Waste products than can be measured in the blood include creatinine and urea nitrogen but there are many other waste products that are not measured by blood tests. The kidneys also acts as a filter to keep "good" substances in the blood. The kidneys regulate the amount of water in the blood by excreting extra water and retaining water to prevent dehydration by varying the amount of urine that is produced. The kidneys help regulate blood pressure by saving or eliminating sodium based on how much sodium the pet is eating. The kidneys help regulate calcium and vitamin D which keep bones strong. The kidneys produce a substance that helps with the creation of new red blood cells. Because the kidneys have so many functions, when the kidneys are not working normally, there are many signs that the pet may show.

CKD is progressive

By the time the pet shows signs of CKD, the damage is severe. There is no cure for CKD. The remaining nephrons are working so hard that with time they will fail as well. CKD is usually fatal in months to years but various treatments can keep the pet comfortable and with a good quality of life for months to years.

Signs of CKD

Because the kidneys perform so many functions, the signs pets with CKD show can vary quite a bit. The signs may be severe or may be subtle and slowly progressive. Despite the chronic nature of the disease, sometimes signs appear suddenly. Some of the more common signs of CKD include:

• drinking too much (polydipsia) and urinating large volumes of urine (polyuria)
• the increased volume of urine in the bladder may lead to, or worsen incontinence (leaking urine), especially at night
• vomiting and/or diarrhea
• lack of appetite and weight loss
• general depression related to the elevation of waste products in the blood
• anemia resulting in pale gums and weakness due to a low blood count
• overall weakness from low blood potassium

Less common signs include

• weakened bones can result in bone fractures
• high blood pressure can lead to sudden blindness
• itchy skin from calcium and phosphorous depositing in the skin
• bleeding into the stomach or gut or bruising of skin

Signs you may see if you examine your pet include: dehydration, weight loss, pale gums and ulcers in the mouth.

The signs seen in pets with CKD and the findings on examination are not specific for CKD and may be seen with many other diseases so blood and urine tests are needed to make a diagnosis of CKD.

Diagnostic Tests

Abnormalities that are often seen on diagnostic blood and urine tests include:

• anemia without signs of a response by the body to the low blood count (non regenerative anemia)
• increased wastes that are normally removed by the kidneys (blood urea nitrogen [BUN] and creatinine)
• increased phosphorus
• calcium is often normal but can be elevated in some pets with CKD and rarely is decreased
• dilute urine
• +/- protein or bacteria in the urine

Sometimes bruising occurs where the blood sample was drawn as pets with CKD may have platelets that are less sticky than normal (normal platelets prevent bruising).

A diagnosis of CKD can usually be made based on the signs, physical examination and blood and urine tests but other tests may be performed to look for an underlying cause for the CKD and/or to "stage" the CKD.

Other tests that may be performed include

1. Determination of kidney size using abdominal radiographs (x-rays) or ultrasound
   What might this test show?  The kidneys in pets with CRD are usually small reflecting the death of a large number of nephrons. If the kidneys are large then certain causes for the CKD should be considered such as lymphoma (cancer) of the kidneys, or an uncommon disease called amyloidosis. Some pets with signs of kidney disease who have large or normal sized kidneys may have acute kidney failure rather than CKD. The treatment and prognosis for pets with acute kidney disease differs from the treatment and prognosis of pets with CKD.
2. Kidney biopsy
   What might this test show?  A biopsy is not required to make a diagnosis of CKD but the results of a biopsy may show a cause for the CKD. A biopsy is more likely to show specific information when the kidneys are big rather than small. A biopsy can be valuable in pets who develop CKD at a young age or who are of a breed known to develop congenital kidney disease. There may be specific microscopic changes in a kidney biopsy from an animal with congenital kidney disease that may suggest that related animals are also at risk for developing CKD. Knowledge that the cause of CKD is caused by congenital kidney disease does not change the treatment of the affected animal but does provide information for related animals, for example if you should remove them from a breeding program. When a biopsy is planned, usually the biopsy is collected using ultrasound or laparoscopy to see the kidney during the biopsy so that no other organs are damaged during the biopsy.
3. Bacterial culture
   What might this test show?  Bacterial infection is not a common cause of CRD but pets with CKD may develop a bacterial infection as several aspects of the pet's immune system may be less functional when the kidneys are failing.  If white blood cells are observed on microscopic examination of the pet's urine, a bacterial culture of the urine should be obtained.
4. Tests of clotting ability
   What might this test show?  If a pet is going to under go kidney biopsy, tests may be performed in advance to evaluate the ability to stop the bleeding from the biopsy site.

Treatment of CRF

The severity of the pet's signs will determine what treatments are needed. Not all treatments presented below may be needed or appropriate for each pet with a diagnosis of CKD. Treatments may also be started incrementally (a few treatments are started and then based on patient response, additional treatments may be added later). The information below is not meant to be a substitute for veterinary care.

Pets with severe signs may be hospitalized for fluid and intravenous drug treatment to reduce the amount of waste products in their body. Many pets with CKD will feel better in response to treatment with IV fluids but if the kidney disease is extremely severe the pet may not respond to treatment.

Those pets who are still eating and not showing severe signs are treated with a variety of treatments, often introducing treatments incrementally as new signs develop. The treatment approach is often called "conservative" compared to more aggressive treatments such as hospitalization for fluid therapy, dialysis or kidney transplantation. Remember that CKD is not a disease that can be cured. Treatments are designed to reduce the work the kidneys need to perform, to replace substances that may be too low (such as potassium) and to reduce wastes that accumulate such as urea (generated by the body from proteins) and phosphorus. The initial response to conservative therapy may be relatively slow, taking weeks to months to see a response.

Diet
Feeding of a kidney diet is usually recommended. Kidney diets contain less protein compared to other diets and the protein is high in quality. It is protein in the diet that is converted to waste products that the kidneys must remove in the urine. The higher the quality of the protein in the diet, the less wastes created for the kidneys to eliminate. Low quality protein requires the kidneys remove more wastes. which makes them work harder. Egg and meat contain higher quality protein; cereal grain protein is of lower quality which leads to more wastes for the kidneys to eliminate. Protein is used by the body to repair cells and tissues that are continually regenerating, so a pet needs some protein in their diet. By feeding a low quantity, but high quality protein diet that contains an appropriate amount of fats and carbohydrates, the pet's body can use the protein for replacing the cells and tissues and use the fat and carbohydrates for energy. Kidney diets also contain a lower amount of phosphorus. Phosphorus accumulates in the blood when the kidneys are diseased. Kidney diets control the amount of other substances that may be too high or too low in patients with CKD such as salt, potassium, magnesium and B vitamins. There are differences in the kidney diets for dogs and cats. When making diet changes it is often beneficial to gradually introduce the new diet by adding increasing amounts of the new diet while reducing the amount of the current diet over 1 to 2 weeks. The pet is more likely to accept a new diet when it is introduced gradually and it is less stressful to the kidneys to gradually adapt to changes in the diet.

Protein restricted diets are less palatable than higher protein diets. Pets with CKD that are still eating are more likely to accept a change in diet to a protein restricted diet than are pets who are very ill and refusing most foods. Protein restricted diets are more expensive than higher protein diets.

There are many pet food companies that sell kidney diets.  Dr. Tony Buffington at the Ohio State University is a good source of information on available diets. http://vet.osu.edu/1442.htm  select a species, a diet form and select Reduced Phosphorous/Protein for a list of diets for pets with kidney disease. Homemade diets can be fed but it is best to work with your veterinarian to formulate a diet that is balanced.

Water
Because pets with kidney disease cannot conserve water by making concentrated urine, their water intake is very important to prevent dehydration. Make sure they always have plenty of fresh water available.  If the pet is not eating well, or is vomiting, then s(he) may not be drinking enough and may get dehydrated. Pets can be encouraged to drink by giving them flavored broths in addition to plain water. The broth should be low in sodium and its best to discuss with your veterinarian other ingredients in the broth to make sure it doesn't contain substances that will make the kidneys work harder.

Water soluble vitamins like B and C are lost in greater amounts when the pet is urinating greater amounts. Kidney diets contain increased amounts of water soluble vitamins so additional vitamins do not need to be given unless a homemade diet is being fed.

Potassium
Lack of appetite and increased loss of potassium in urine may result in low body potassium (hypokalemia).  Cats with CKD are more likely to have low body potassium than are dogs. Cats with low potassium may develop painful muscles. Both cats and dogs may be weak when potassium is low. Cat kidney diets contain higher levels of potassium so additional supplementation is probably not needed unless the cat shows signs of muscle pain.  Potassium gluconate or citrate can be given by  mouth if potassium supplementation is needed. Potassium chloride is acidifying and is not recommended.

Phosphorus, calcium and PTH
Pets with CKD usually have increased blood phosphorus. In health, phosphorus and calcium are controlled by a hormone called parathyroid hormone (PTH). PTH works with vitamin D on the intestine, kidney and bone to keep calcium and phosphorus normal.  As the kidneys fail the amount of PTH in the body is elevated and the amount of vitamin D is reduced. Elevated PTH itself may be responsible for some of the signs shown by pets with CKD.  PTH draws calcium and phosphorus from the bones which can weaken bones which can lead to bone fracture.

Kidney diets typically contain reduced phosphorus and an appropriate amount of calcium but if phosphorus remains elevated when the pet is eating a kidney diet then phosphorus can be tied up in the intestinal tract so it can be eliminated in the stool. Intestinal phosphate binding agents include aluminum carbonate, aluminum hydroxide, aluminum oxide, calcium citrate, calcium acetate and calcium carbonate and sevelamer hydrochloride.  Phosphate binding agents which contain calcium should not be used until blood phosphorus is normal to prevent calcium and phosphorus from combining and precipitating in tissues including the kidneys. It is not usually necessary to give additional calcium but if a pet has low blood calcium, the phosphorus should be normalized before giving calcium.  Even when blood phosphorus is normalized, PTH levels are still higher than normal. The administration of low doses of vitamin D (1, 25 dihydroxycholecalciferol [calcitriol]) will suppress PTH and possibly  slow the rate of progression of kidney deterioration.

It is not 100% agreed that giving your pet calcitriol will slow the deterioration of the kidneys.

Here are some web sites on using calcitriol http://members.bellatlantic.net/~vze2r6qt/calcitriol/

Acidosis
Some pets with CKD will have an acid blood pH.  Kidney diets are designed to counteract the acidosis but very sick animals that are hospitalized may need addition treatment to correct the acidosis.

Sodium
Diseased kidneys are less efficient at regulating sodium and sodium in turn helps control blood volume and pressure. Excess sodium can lead to water retention and not enough sodium can lead to dehydration. When changing diets that contain different amounts of sodium (kidney diets usually have less sodium than regular diets) make the change  gradually over several weeks. Use caution when giving your pet table scraps or treats that may be high in sodium.

High blood pressure (hypertension)
Many pets with CKD have high blood pressure. High blood pressure can contribute to further decline of kidney function and can occasionally lead to sudden blindness from retinal detachment. Ideally blood pressure should be measured by your veterinarian and hypertension confirmed before giving drugs to treat high blood pressure but measuring true blood pressure in dogs and cats can be difficult.  If the pet has an elevation in blood pressure it may be due to the excitement of being examined or due to CKD. The calmer you are able to keep your pet during examination, the more reliable the readings for blood pressure. There are several drugs that may be used to manage high blood pressure including enalapril, benazepril, or amlodipine (and others).  Enalapril and benazepril are in a class of drugs called <align="left"> ACE inhibitors and are sometimes used in pets with CKD that have abnormal amounts of protein in their urine even when blood pressure is normal.

Anemia
The kidneys play a role in producing a hormone called erythropoietin which stimulates the production of new red blood cells. Red blood cells live about a hundred days so new cells are continually being made. Less erythropoietin is made in pets with CKD leading to anemia.  The packed cell volume (PVC) (also called hematocrit) is the percentage of blood cells compared to fluid in whole blood. When the PCV is ~20 in cats and ~ 25% in dogs, anemia may contribute to lack of activity and weakness.

Anemia can be treated by blood transfusion or by the administration of human erythropoietin. Erythropoietin is very effective in increasing PCV but because human erythropoietin is not exactly the same as dog and cat erythropoietin, over time, the pet may form antibodies that cause the medication to become ineffective. Canine and feline erythropoietin are currently being studied.

Fats/lipids
Certain types of fats (polyunsaturated omega 6 fatty acids) may slow the decline in kidney function are are often present in kidney diets.

Subcutaneous Fluids
Some cats and dogs with kidney disease may not drink enough to prevent becoming dehydrated and may benefit from the administration of intermittent SC fluids. If your veterinarian feels your pet may benefit from giving subcutaneous fluids, we provide some instructions on how to give SC fluids.  See Cat Fluids or Dog Fluids

Lack of Appetite
The accumulation of wastes in the body often decreases appetite. A goal of several of the above treatments is to reduce the amount of wastes in the blood. If the pet remains off food despite above treatments you might try different brands of renal failure diets, warming the food or adding odiferous toppings to entice the pet to eat.

Vomiting
Increased levels of waste products cause the pet to vomit. Your veterinarian may recommend medications that reduce nausea or act directly on brain centers to reduce the urge to vomit.

Drugs used to treat other diseases
Because the kidneys are responsible for elimination of many drugs, make sure that your veterinarian is aware of any other medications you are giving your pet as these may accumulate in the body to toxic levels if the kidneys cannot eliminate them.

Antibiotics
If the urine shows signs of infection or if a urine culture grows bacteria then antibiotics may be administered. If a urinary tract infection is involving the kidneys, the period of treatment is much longer than a infection of the bladder.

Avoiding Stress

You are in the best position to judge what is stressful to your pet. When a pet is stressed they may drink and eat less than normal. Reduced water intake is detrimental to diseased kidneys. When possible, keep your pet calm. That might mean for example: having an in-home pet sitter if your pet is stressed by boarding, removing the pet from the household during a party or limiting contact with other animals if these situations appear to be a source of stress for your pet. Extremes in heat or cold are stresses.  Certain drugs such as prednisone/cortisone make the kidneys work harder.

Kidney Transplantation

There has been progress made in transplantation of kidneys, more for cats than for dogs.

See http://www.felinecrf.com/transb.htm  for a list of facilities that currently offer transplanation.

As the male kitten grows the testicles become more apparent.

The color of the kitten may suggest its gender. Almost all (but not ALL) kittens of calico (black, white and orange) or tortishell (black and orange) color are females. More orange kittens are male than female although the association between color and sex is not as strong as in the calico/tortishell colored kitten.

The results of laboratory tests may be influenced by drugs your pet is receiving and some are influenced by a recent meal. Always provide your veterinarian with information about any drug your pet is receiving. Inquire when you make an appointment for veterinary care, whether you should fast your pet before the visit in case laboratory samples are collected.

Complete blood count (CBC)
The complete blood count measures the number of cells of different types circulating in the bloodstream. There are three major types of blood cells in circulation; red blood cells (RBC), white blood cells (WBC), and platelets. Red blood cells are produced in the bone marrow, which is the soft center of bones. RBCs pick up oxygen brought into the body by the lungs, and bring that oxygen to cells throughout the body. Red blood cells live in the blood stream for about 100 days although the actual time varies with the type of animal. Old red blood cells are removed from the blood stream by the spleen and liver. Red blood cell numbers can be decreased (anemia) if they are not produced in adequate numbers by the bone marrow, if their life span is shortened (a condition called hemolysis), or if they are lost due to bleeding. Increased red blood cell numbers is called polycythemia and is usually due to concentration of the blood due to dehydration. 

The complete blood count also includes a measure of hemoglobin, which is the actual substance in the red blood cell that carries oxygen.

There are several types of white blood cells in blood, including neutrophils (PMNs), lymphocytes, monocytes, eosinophils and basophils. Lymphocytes are produced in lymph nodes throughout the body. The other white blood cell types are produced in the bone marrow along with the red blood cells and platelets. The majority of white blood cells in circulation are neutrophils, which help the animal fight infections. Neutrophils can be decreased in pets with bone marrow disease, in some viral diseases, and in some pets receiving cancer chemotherapy drugs. Neutrophils are increased in pets with inflammation or infection of any part of the body and in pets receiving prednisone or other cortisone-type drugs. 

Lymphocytes also help fight infection and produce antibodies against infectious agents (viruses, bacteria, etc.). Lymphocytes may be increased in puppies and kittens with an infection, they can be decreased in pets who are severely stressed, and lymphocytes might be lost in some types of diarrhea. Certain drugs, such as prednisone (a cortisone-type drug) will decrease the number of lymphocytes in the blood stream. 

Monocytes may be increased in pets with chronic infections. Eosinophils and basophils are increased in pets with allergic diseases, or parasitic infections (worms, fleas, etc.). 

Platelets are produced in the bone marrow and are involved in the process of making a blood clot. Platelets live a few weeks and are constantly being produced by the bone marrow. Low platelet counts occur if the bone marrow is damaged and doesn’t produce them, or if the platelets are destroyed at a faster rate than normal. The two primary causes of platelet destruction are immune-mediated destruction (ITP or IMT) and DIC (disseminated intravascular coagulation). Immune-mediated thrombocytopenia happens when the animal’s immune system destroys platelets. DIC is a complex problem in which blood clots form in the body using the platelets faster than the bone marrow can produce new ones. Animals with a low platelet count bruise easily and may have blood in their urine or stool.

Packed cell volume (PCV) (called hematocrit, HCT, in humans) is another measure of red blood cells. A small amount of blood is placed in a tiny glass tube and spun in a centrifuge. The blood cells pack to the bottom of the tube and the fluid floats on top. The PCV is the percent of blood, that is cells, compared to the total volume of blood. In normal dogs and cats, 40-50% of the blood is made up of blood cells and the remainder is fluid.

Blood and urine tests are performed to get an initial overview of the health, and sometimes the function, of body organs. Some blood tests are very specific for a single organ, whereas other tests are affected by several organs. Blood tests are often performed as a biochemistry profile, or chemistry panel, which is a collection of blood tests to screen several organs at one time. The makeup of a biochemical profile varies with the laboratory in which it is performed. Following are some of the more commonly performed chemical tests:

Albumin is a small protein produced by the liver. Albumin acts as a sponge to hold water in the blood vessels. When blood albumin is decreased, the pressure created by the heart forcing blood through the blood vessels causes fluid to leak out of the blood vessels and accumulate in body cavities such as the abdominal cavity or in tissues as edema. Albumin is decreased if the liver is damaged and cannot produce an adequate amount of albumin or if albumin is lost through damaged intestine or in the urine due to kidney disease. The only cause of increased albumin is dehydration.

Alkaline phosphatase originates from many tissues in the body. When alkaline phosphatase is increased in the bloodstream of a dog the most common causes are liver disease, bone disease or increased blood cortisol either because prednisone or similar drug is being given to the pet or because the animal has Cushing's disease (hyperadrenocorticism). In cats, the most common causes of increased alkaline phosphatase are liver and bone disease.

ALT is an enzyme produced by liver cells. Liver damage causes ALT to increase in the bloodstream. ALT elevation does not provide information as to whether the liver disease is reversible or not.

Amylase is an enzyme produced by the pancreas and the intestinal tract. Amylase helps the body breakdown sugars. Amylase may be increased in the blood in animals with inflammation (pancreatitis) or cancer of the pancreas. Sometimes pancreatitis is difficult to diagnose and some dogs and cats with pancreatitis will have normal amounts of amylase in the blood. Lipase is another pancreatic enzyme which is responsible for the breakdown of fats and which may be increased in patients with pancreatic inflammation or cancer.

Bile acids are produced by the liver and are involved in fat breakdown. A bile acid test is used to evaluate the function of the liver and the blood flow to the liver. Patients with abnormal blood flow to the liver, a condition known as portosystemic shunt will have abnormal levels of bile acids. The bile acid test measures a fasting blood sample and a blood sample two hours after eating.

Bilirubin is produced by the liver from old red blood cells. Bilirubin is further broken down and eliminated in both the urine and stool. Bilirubin is increased in the blood in patients with some types of liver disease, gallbladder disease or in patients who are destroying the red blood cells at a faster than normal rate (hemolysis). Large amounts of bilirubin in the bloodstream will give a yellow color to non-furred parts of the body, which is called icterus or jaundice. Icterus is most easily recognized in the tissues around the eye, inside the ears and on the gums.

BUN (blood urea nitrogen) is influenced by the liver, kidneys, and by dehydration. Blood urea nitrogen is a waste product produced by the liver from proteins from the diet, and is eliminated from the body by the kidneys. A low BUN can be seen with liver disease and an increased BUN is seen in pets with kidney disease. The kidneys must be damaged to the point that 75% of the kidneys are nonfunctional before BUN will increase. Pets that are severely dehydrated will have an increased BUN as the kidneys of a dehydrated patient don’t get a normal amount of blood presented to them, so the waste products do not get to the kidneys to be eliminated.

Calcium in the bloodstream originates from the bones. The body has hormones, which cause bone to release calcium into the blood and to remove calcium from the blood and place it back into bone. Abnormally high calcium in the blood occurs much more commonly than low calcium. High blood calcium is most commonly associated with cancer. Less common causes of elevated calcium are chronic kidney failure, primary hyperparathyroidism which is over-function of the parathyroid gland, poisoning with certain types of rodent bait and bone disease. 

Low blood calcium may occur in dogs and cats just before giving birth or while they are nursing their young. This is called eclampsia and occurs more commonly in small breed dogs. Eclampsia causes the animal to have rigid muscles which is called tetany. Another cause of low blood calcium is malfunction of the parathyroid glands which produce a hormone (PTH) that controls blood calcium levels. Animals poisoned with antifreeze may have a very low blood calcium.

Cholesterol is a form of fat. Cholesterol can be increased in the bloodstream for many reasons in dogs. It is much less common for cats to have increased cholesterol. Some of the diseases that cause elevated cholesterol are hypothyroidism, Cushing's disease, diabetes and kidney diseases that cause protein to be lost in the urine. High cholesterol does not predispose dogs and cats to heart and blood vessel disease as it does in people.

Creatinine is a waste product that originates from muscles and is eliminated from the body by the kidneys. An elevation of creatinine is due to kidney disease or dehydration. Both creatinine and BUN increase in the bloodstream at the same time in patients with kidney disease.

Creatinine kinase (CK) is released into the blood from damaged muscle. Elevation of creatinine kinase therefore suggests damage to muscle including heart muscle.

Glucose is blood sugar. Glucose is increased in dogs and cats with diabetes mellitus. It may be mildly increased in dogs with Cushing's disease. Glucose can temporarily increase in the blood if the dog or cat is excited by having a blood sample drawn. This is especially true of cats. A quick test to determine whether a glucose elevation is transient or permanent is to look at the urine. If the glucose is chronically elevated there will be an increased amount of glucose in the urine as well.

Low blood sugar occurs less commonly and can be a sign of pancreatic cancer or overwhelming infection (sepsis). Low blood sugar can cause depression or seizures. Low blood sugar can be seen if the blood sample is improperly handled. Red blood cells will use glucose so typically red blood cells are removed from the blood sample and the clear part of the blood (plasma or serum), is used for analysis.

Phosphorus in the bloodstream originates from bones and is controlled by the same hormone, PTH (parathyroid hormone) which controls blood calcium. Phosphorus is increased in the bloodstream in patients with chronic kidney disease. Like BUN and creatinine, phosphorus increases in these patients when about 75 percent of both kidneys is damaged.

Potassium is increased in the bloodstream in the pet with acute kidney failure such as kidney failure caused by antifreeze poisoning, in dogs with Addison's disease and in animals with a ruptured or obstructed bladder. 

Potassium is lost from the body in vomit, diarrhea and urine. Pets that are not eating may have a low blood potassium. Low blood potassium can cause the pet to feel weak. Cats with low potassium may develop painful muscles.

Sodium may be slightly increased in the blood if the patient is dehydrated although many dehydrated dogs and cats have a normal blood sodium. Low blood sodium is most commonly seen with Addison's disease (hypoadrenocorticism).

Total protein includes albumin and larger proteins called globulins. Included in the globulins are antibodies which are protein molecules. Total protein can be increased if the dog or cat is dehydrated or if the pet's immune system is being stimulated to produce large amounts of antibody. Total protein is decreased in the same situations which reduce albumin or if the pet has an abnormal immune system and cannot produce antibodies.

Urinalysis: A urine sample can provide information about several organ systems. The concentration, color, clarity and microscopic examination of the urine sample can provide diagnostic information.

Urine may be obtained by catching a sample during normal urination, by passing a catheter into the bladder or by placing a small needle through the body wall into the bladder, a procedure called cystocentesis. Depending upon why the urine sample is being collected, one collection method may be preferred over another. Inquire at the time you make an appointment for veterinary care if a urine sample may be collected. Preventing your pet from urinating prior to the appointment will assure that your pet’s bladder will contain urine for sampling.

Lyme disease was first described in 1975 when an unusual outbreak of  rheumatoid arthritis occurring in children was reported in Lyme, Connecticut. In 1982, the bacteria Borrelia burgdorferi was determined to be the cause of that outbreak. Since Lyme disease was first described in the early 1980's, the frequency of occurrence of disease has increased twenty-five fold. Today, Lyme disease is the most common vector-borne (transmitted by insects or arthropods) disease occurring in people and probably in dogs in the United States. Dogs are most frequently infected with the Lyme disease bacteria, but infections can also occur in horses, cattle, and cats.

How is Lyme disease transmitted?
The bacteria live in mice, deer and other small mammals. The type of ticks that can transmit the bacteria from these wildlife  to humans and domestic animals are the Ixodes ticks.  The bacteria replicate (increase in number) in the  wildlife without causing them to become sick. When a tick feeds on the infected wildlife the tick picks up the bacteria, then they transmit the bacteria to another animal the next time they feed.  

If your pet is diagnosed with Lyme disease you are not at risk of getting Lyme disease directly from your pet. The bacteria increase to high levels in the blood of wildlife whereas humans and domestic animals develop very low levels of the bacteria in their blood and these low levels will not infect a feeding tick.   Researchers have learned that infected ticks must feed for about 24 hours to transmit the bacteria to a susceptible animal so quick removal of ticks from your pet reduces the chance of infection.

Clinical signs 
The most common sign of Lyme disease in dogs is arthritis, which causes sudden lameness, pain ands sometimes swelling in one or more joints.  Other signs that may be seen include fever, lack of appetite, dehydration, inactivity, and swollen lymph nodes. In severe cases, the infection can cause kidney failure and death although this does not occur commonly in dogs. The signs of heart and nervous system dysfunction seen in infected humans are not often seen in animals.

 Diagnosis 
A diagnosis of Lyme disease is usually made based upon a history of  being in an endemic area, signs of arthritis and favorable response to treatment. There is a blood test that measures antibodies to the bacteria but many dogs that live in endemic regions will have a positive blood test. A positive blood test just means that the dog was exposed to Borrelia burgdorferi  but not all dogs that are exposed will show signs of disease.  Early in the disease dogs may not yet have a positive blood test. Dogs that have been vaccinated for Lyme disease may have a positive blood test depending upon the type of blood test that is performed. There are several other causes of arthritis that occur in dogs that must also be considered.

Treatment
Borrelia burgdorferi  is easily treated with antibiotics. The signs of Lyme disease usually regress rapidly in response to treatment. If the disease remains untreated the disease becomes chronic and can cause kidney damage although dogs are much less likely to develop chronic disease than are people.

Prevention
Animals in endemic areas are at greatest risk for infection. The best method of prevention is to avoid tick infested areas, especially in the spring when the young ticks are most active. When returning from a tick-infested area do a thorough search for ticks on both yourself and your animals. Ticks should be removed carefully with a tweezers, pinching the tick near the point they enter the skin. There are also many highly effective veterinary products that will kill ticks on your dog before the tick can transmit the bacteria. Remember that early removal of ticks reduces the chance that the tick will transmit Lyme disease.

There is a vaccine approved for use in dogs for Lyme disease prevention. Most authors of veterinary articles on Lyme disease do not recommend vaccinating dogs in non-endemic areas. Not all authors agree on how effective the vaccine is in preventing Lyme disease and not all authors agree that the vaccine should be given in endemic regions. The vaccine can cause some blood tests for Lyme disease to become positive. For more information about tick control products or Lyme disease, consult your veterinarian.

References:
For additional information on Lyme disease see: the Centers for Disease Control (CDC) website

This topic was written by Wendy Harless, Oregon State University, class of 2002 with the guidance of Dr.Diana Stone, Washington State University.

What you might see/ Clinical presentation

The presentation of dogs with LSA is highly variable as lymphocytes can be found in virtually any organ in the body. Nonetheless, the most common form (referred to as stages) of LSA causes a non-painful enlargement of one or more lymph nodes that can be seen or felt from the body surface. Occasionally, a lymph node becomes large enough to impair function (obstruction of blood flow or airway, for example). Other forms of LSA can involve the liver, spleen, bone marrow and gastrointestinal tract, skin or nervous system (and other organs) and the clinical signs will reflect the organ system involved (e.g. vomiting or diarrhea with gastrointestinal forms; weakness or pale mucous membranes and others that reflect impaired production of blood cells from the bone marrow); many dogs will simply feel ill (lose appetite, become lethargic) with any of the different forms. In some dogs, lymph node enlargement is an incidental finding when an otherwise healthy-appearing dog is seen by a veterinarian for an unrelated reason (e.g. vaccination).

Lymph node staging

Stage I: single lymph node enlarged 
Stage II: multiple nodes enlarged on either the front half or back half of the body 
Stage III: multiple nodes enlarged on both front and back halves of body 
Stage IV: involvement of the liver and/or spleen 
Stage V: bone marrow involvement, or involvement of other organs (e.g. gastrointestinal, skin, nervous system) 
Each numbered stage can be further divided into substages, of which there are two: a and b. Patients with substage a feel well while patients with substage b are ill.

Biological behavior of LSA

LSA is viewed as a systemic disease, and as such is not really viewed to "spread" to other organs. This tumor is not generally viewed as a curable tumor in dogs, although occasional dogs will experience what seems to be a cure with appropriate treatment (see below). A dog can start with one stage of the disease and progress over time to another (usually more advanced) stage of LSA.

Clinical staging (determination of the extent of the tumor)

Because of the organs that LSA commonly involves, staging a dog with a LSA can involve aspiration of one or more lymph nodes, thoracic radiographs abdominal radiographs or ultrasound (to look for big nodes in the abdomen and to look at the liver and spleen), or bone marrow examination. Often, obtaining blood for a complete blood count and biochemical profile, and a urinalysis will be advised as these can help assess overall health and provide information that potentially influences treatment recommendations. Sometimes, special stains to determine if the LSA is of B-cell or T-cell origin (B-cells and T-cells are specific types of lymphocytes) are recommended because of prognostic significance, although treatment recommendations are the same for either type.

Treatment options

The mainstay of treatment of LSA is administration of chemotherapy drugs; the best responses in terms of length of tumor control and survival are generally seen with protocols that entail administration of more than one chemotherapy drug, although there are approaches that involve administration of a single drug. Chemotherapy drugs commonly used include: doxorubicin, vincristine, cyclophosphamide, prednisone, and L-Aspariginase, but many others are also used. In some dogs with very localized disease, surgery or radiation therapy can play a role in treatment, although chemotherapy is still often recommended in these cases.

Prognosis

The prognosis of dogs with LSA is highly variable, and depends on the clinical stage (ill dogs fare more poorly than dogs that feel well, and dogs with Stage V disease are generally considered to have a poorer prognosis), the type of tumor (dogs with B-cell LSA usually do better than dogs with T-cell LSA). Most dogs treated with chemotherapy will experience a remission, a period in which there is no detectable cancer and the dog feels well. Remission times are variable, but most dogs with the lymph node forms of LSA will have initial remissions lasting in the range of 6-9 months before evidence of the tumor is seen again; second remissions can be achieved in many of these dogs, but any subsequent remission is expected to be shorter in duration than the first remission. Survival times for most dogs treated with combination chemotherapy protocols are in the range of approximately 1 year. And even though an individual dog will have received a lot of chemotherapy over that year, their quality of lfe is generally very good. Statistics, while useful, can never predict how an individual dog will fare with or without specific treatment.

Future treatment options:

New protocols are tried with great regularity in canine lymphoma but results have been similar with each drug regime investigated. Most likely our survivals will always be similar until we either accept greater toxicity (meaning most dogs will be very sick from the treatment and some may even die), or a completely novel treatment is invented. Using half or whole body radiation therapy may prove helpful. The development an antibody specific for dog lymphoma, which could recognize all dog lymphomas and yet no normal lymphocytes, and be attached to a toxin or other cell killing mechanism, is a far off dream.

Key points

LSA is one of the most chemotherapy-responsive tumors seen in veterinary medicine, and most dogs tolerate chemotherapy very well with minimal impact on their quality of life. If you notice fast growing lumps on your dog that seem to be in the area of the major joints (at the neck, in front of the shoulders, in the armpits, at the back of the knees or in the groin) have your dog examined soon by a veterinarian even if he feels well. Remember, lower stage disease, and dogs that feel well, will do better with treatment than dogs that are ill and/or have more advanced disease.

What you might see/ Clinical presentation

Cats with LSA present with a variety of signs because lymphocytes can be found in nearly every organ in the body. Also, cats seem to have more forms of LSA in atypical locations or not in normal lymphoid tissues, as compared to other species. Most species including man present with large lymph nodes, but this is a rare form of LSA in cats. Young cats typically present for masses in the chest cavity and owners notice signs of difficulties breathing or vomiting of food. Older cats develop the tumor in their intestines quite commonly and owners may notice signs such as weight loss, diarrhea or vomiting. They also can however develop LSA in areas as diverse as the nasal passages, kidneys, spinal cord, liver, eyes, or a single lymph node, and the signs seen will be more specific for the organ affected. Because cats present with such a variety of organs affected there is no valid staging system for feline LSA and a cat diagnosed with the disease will more likely be staged by the organ affected (eg. gastrointestinal LSA, mediastinal LSA etc.)

Biological behavior of LSA

Even though many cats present with only a single site of involvement, LSA is viewed as a systemic disease. Lymphocytes in their normal functioning capacity travel throughout the body and as a cancer the disease is also moving though not in a classical sense "metastasizing". Even if a tumor diagnosed as LSA has been surgically removed the disease is not gone.

Clinical staging (determination of the extent of the tumor)

Because of the organs that LSA commonly involves, staging a cat with a LSA can involve aspiration of one or more lymph nodes or masses, thoracic radiographs abdominal radiographs or ultrasound (to look for big nodes in the abdomen and to look at the liver and spleen), or bone marrow examination. Obtaining blood for a complete blood count and biochemical profile, FeLV, FIV, and a urinalysis is always advised as these can help assess overall health and provide information that potentially influences treatment recommendations. Sometimes, special stains to determine if the LSA is of B-cell or T-cell origin (B-cells and T-cells are specific types of lymphocytes) are recommended because of prognostic significance, although treatment recommendations may be the same for either type. Staging the disease can be critical in choosing treatment protocols.

Treatment options

Chemotherapy should always be considered a critical part of the treatment for LSA. The best responses in terms of length of tumor control and survival are generally seen with protocols that entail administration of more than one chemotherapy drug, although there are approaches that involve administration of a single drug. Chemotherapy drugs commonly used include: doxorubicin, vincristine, cyclophosphamide, prednisone, and L-Aspariginase, but many others are also used. Some protocols are very aggressive and relatively short (six month total) and others are less aggressive but extend for one to two years. The decision of which protocol is to be used does depend on the results of the tumor biopsy (not all LSA is the same) and the staging results. Thankfully, the chemotherapy generally act quickly so that even cats with sever signs can have relief fairly soon after starting therapy (sometimes as quickly as 24 hours). Surgery is sometimes recommended as a part of the treatment but this is usually either to reach a diagnosis or to remove a potentially life threatening problem (for example intestinal rupture due to a tumor mass). Surgery is never curative and should always be followed by chemotherapy to best extend the cat’s life. Radiation can also play a role in the treatment of very localized LSA. The primary site most benefiting from radiation therapy is nasal LSA.

Prognosis

Cats with LSA have unpredictable responses and survivals. Depending on the site of the tumor, mean survivals with chemotherapy range from 6-9 months. The problem is that this is only an average and most cats tend to do either much worse or much better. Young cats, FeLV negative, with mediastinal LSA are quite regularly cured with chemotherapy; cats with LSA in their central nervous system typically have a bad prognosis, but most other forms of LSA in cats have unpredictable outcomes. Generally it is best to at least try a chemotherapy protocol because it may be the only way to see how an individual cat will do. Cats often do not enjoy receiving chemotherapy, but veterinary oncologist try hard to make the regime tolerable for each feline patient even if it means modifications in a protocol. 

Future treatment options

New protocols are tried in feline lymphoma but results have been similar with each drug regime investigated. Most likely our survivals will always be similar until we either accept greater toxicity (meaning most cats will be very sick from the treatment and some may even die), or a completely novel treatment is invented. Using half or whole body radiation therapy may prove helpful. The development an antibody specific for cat lymphoma, which could recognize all cat lymphomas and yet no normal lymphocytes, and be attached to a toxin or other cell killing mechanism, is a far off dream.

Key points

LSA is one of the most chemotherapy-responsive tumors seen in veterinary medicine and cats can tolerate chemotherapy relatively well, or protocols can be modified so that an individual cat can maintain a good quality of life while on chemotherapy. Unfortunately we have few strong predictors of which cats will have good responses to chemotherapy and long survivals, and survival is therefore difficult to estimate at the outset. Often the only way to know how a cat will respond to treatment, is to start treatment. 

What you might see/ Clinical presentation

MCT most commonly are seen as solitary lumps or masses in or underneath the skin; occasional dogs can have multiple masses from MCT. MCT can look like just about anything, ranging from benign-appearing lumps (such as a lipoma), to more angry or ulcerated lumps, masses with a stalk or focal thickenings in the skin. MCT may change quickly in size (become larger then smaller ) because of reactions around the mass. Some dogs may have signs of systemic disease, which can be caused by some of the biologically active compounds found within mast cells. In most cases, evidence of a MCT is easily generated by examination of a fine-needle aspirate of the suspect mass, and aspiration is advised before removal of a mass to be sure it is not a MCT (or other skin malignancy), a finding that would demand a more aggressive surgical removal. Often, obtaining blood for a complete blood count and biochemical profile, and a urinalysis will be advised as these can help assess overall health and provide information that potentially influences treatment recommendations.

Biological behavior of mast cell tumors

Most mast cell tumors are considered locally invasive, and can be difficult to remove completely because of the extent of local spread. The behavior of mast cell tumors reflects their grade (a term used by pathologists and oncologists to describe such things as how-well differentiated a tumor is, how frequently it is dividing, how invasive to adjacent structures, and other criteria). Mast cell tumors have 3 grades, with grade I being the least aggressive and least likely to spread to other organs (metastasize), and grade III being highly aggressive tumors with a high likelihood of metastasis; most grade II tumors tend not to metastasize, although they can do so. Mast cell tumors show a predilection to spread to regional lymph nodes, liver, spleen, and bone marrow.

Clinical staging (determination of the extent of the tumor)

Because of the organs to which these tumors like to spread (metastasize) to, staging a dog with a mast cell tumor (usually reserved for occasional grade I tumors, most grade II tumors and all grade III tumors) entails collection of cells from regional lymph nodes for microscopic examination, imaging the thorax (radiographs) and abdomen (radiographs, abdominal ultrasound) for enlargement of lymph nodes, liver or spleen, and some assessment of bone marrow involvement, either a bone marrow collection for microscopic examination, or examination of the white blood cells for circulating mast cells (interpreted to mean that mast cells are in the bone marrow).

Treatment options

Surgical removal is the mainstay of treatment of canine mast cell tumors. Because of their locally invasive behavior, wide margins of what appears to be normal tissue around the tumor needs to be removed to increase the likelihood that the tumor has been completely removed. For mast cell tumors that were not, or because of location, could not be completely removed, radiation therapy is often the best treatment for residual disease, although a more aggressive second surgery is possible for some dogs. Chemotherapy is sometimes used to treat mast cell tumors, but chemotherapy is usually reserved for dogs with grade III tumors; mast cell tumors are notoriously unpredictable tumors with regards to response to chemotherapy. In addition to treatment of the tumors, some dogs will be treated with medications that tend to help fight the secondary effects of the tumor. These usually include drugs like prednisone, an anti-histamine like Benadryl, and an antacid type medication like Pepcid.

Prognosis

The prognosis for completely removed grade I and grade II tumors is excellent. The prognosis for incompletely removed grade I and II tumors treated with radiation therapy after surgery is also excellent with approximately 90-95% of dogs having no recurrence of tumor within 3 years of receiving radiation therapy. The prognosis for dogs with grade III tumors is considered guarded as local recurrence and/or spread is likely in most dogs. If your dog is diagnosed with a grade III Mast cell tumor most likely chemotherapy will be recommended as at least part of the protocol. Drugs used at WSU include Lomustine and Vinblastine.

Future treatment options

Mast cell tumors have been examined for mutations in a certain gene known as c-kit. This c-kit gene belongs to a family of genes codes for receptor tyrosine kinases. Receptor tyrosine kinase inhibitors are an active part of cancer treatment research in the human field and these drugs are being looked at treatments for canine Mast cell tumors as well. No drug is currently available commercially.

Key points

Dogs that develop Mast cell tumors seem to like to develop more of them and this is not necessarily the same as metastasis. So any dog diagnosed with a mast cell tumor must be watch closely in the future for the development of new tumors. As long as tumors are caught when small, surgical removal is usually adequate for treatment. Mast cell tumors can also be very unpredictable tumors. Even grade I and II tumors can behave aggressively in terms of metastasizing and or being difficult to control locally, in any given individual dog. Statistics, while useful, can never predict how an individual dog will fare with or without specific treatment.

What you might see/ Clinical presentation

The most common sign seen in dogs with OSA is lameness. Lameness may develop suddenly (for example, after vigorous activity), or may develop more slowly. Depending on the location of the tumor, a swelling or mass-like effect could be seen in the affected leg. Any lameness in a large-breed dog that does not promptly resolve with symptomatic therapy should be further investigated (examination, radiographs).

Biological behavior of Osteosarcoma

OSA is both a locally invasive tumor and a tumor with a high likelihood of spread (metastasis) to other organs, most commonly the lung, although metastasis to other organs is possible. Most (approximately 90-95%) of dogs with OSA are considered to have metastasis at the time of their diagnosis, although metastasis will only be evident at the time of diagnosis in approximately 10% of dogs and in others the metastatic tumors are considered to be microscopic. Tumors in bone are quite painful to affected dogs, accounting for the lameness that is seen as the most common presenting complaint in affected dogs.

Clinical staging (determination of the extent of the tumor)

Radiographs of the affected leg, and radiographs of the thorax are the most critical elements of clinical staging; dogs with enlarged lymph nodes will also typically have the lymph nodes sampled for microscopic examination. Radiographs of affected legs are often highly suggestive of the diagnosis, and biopsies are not necessary for all dogs with compatible lesions on radiographs. Often, obtaining blood for a complete blood count and biochemical profile, and a urinalysis will be advised as these can help assess overall health and provide information that potentially influences treatment recommendations. When aggressive therapy is being considered, a CT examination of the lungs will also be recommended to screen the lungs for metastasis even more precisely than the radiographs can show us.

Treatment options

Amputation to remove the primary tumor, combined with chemotherapy to treat the metastatic disease we can’t yet see, is the best treatment for preservation of quality (relief of pain) and quantity of life for dogs with the limb form of OSA. Not every dog is a candidate for amputation and the decision to amputate is often difficult for owners. Dogs with severe arthritis in the unaffected limbs, or weakness due to neurologic disease may not be candidates for amputation but most other dogs are. Dogs can function on three legs much better than most owners think. Some institutions offer limb-sparing surgery, in conjunction with chemotherapy, but this can only be done when the tumor is in the radius or ulna near the carpal joint (wrist). Not every owner is prepared for the expense and time commitment to chemotherapy either. Generally therapy is done once every 3-4 weeks for 5 doses of chemotherapy. Drugs commonly used include cisplaitn, carboplatin and doxorubicin. Amputation without chemotherapy can remove the source of pain, but generally metastases will become apparent in 3-4 months. 

Palliative therapies are those aimed at keeping the leg more comfortable so that the dog can live with it longer. There is no benefit expected in most dogs from the administration of chemotherapy drugs if the primary tumor is not removed. Radiation therapy will improve comfort in approximately 70-80% of treated dogs. Generally only a few large doses of radiation are administered. Administration of analgesics, which can be done in conjunction with palliative radiation therapy, can improve the level of comfort in some dogs. Additionally a class of drugs known as bis-phosphonates is being tried for dogs with osteosarcomas. These drugs inhibit bone resorption, or break down. They have been use in the human field for osteoporosis but also in the treatment of tumors which have metastasized to bone to relieve bone pain. Clinical trials are underway to determine if these drugs actually relieve pain in primary bone tumors of dogs. 

Dogs with OSA in other bone locations are often treated with a combination of surgery, radiation therapy and chemotherapy.

Prognosis

The prognosis for dogs undergoing surgery to remove the primary limb tumor (ampuation or limb-sparing surgery) and treated with chemotherapy is fair to good. About half of dogs with OSA treated in this manner will be alive 1 year after diagnosis; approximately 25% of dogs treated in this fashion are alive 2 years after diagnosis, and occasional dogs will be cured. Dogs treated with either amputation or palliative radiation therapy live, on average, approximately 6 months before complication of the local tumor or metastatic disease cause death or prompt euthanasia.

Future treatment options

Many therapies being developed in the human field aimed at stopping metastatic disease could be helpful in dogs with osteosarcomas. Bisphosphonate drugs may also prove useful for palliation of tumor pain, particularly when combined with palliative radiation therapy. A Gene therapy trial administering a gene coding for a potent immune stimulant (IL-2) has shown promise in preliminary studies. 

Key points Most dogs do amazingly well with three legs; amputation, however, is not appropriate for all dogs, particularly those with other orthopedic or neurologic diseases. For such patients, palliative radiation therapy is considered an excellent treatment alternative with a high likelihood of improving patient comfort. Unfortunately, most dogs will die from complications of OSA. Statistics, while useful, can never predict how an individual dog will fare with or without specific treatment.

Other helpful sites

Canine Cancer Awareness

Canine Osteosarcoma

Idiopathic epilepsy

Idiopathic epilepsy is another common cause of seizures in dogs and less commonly in cats. It is by definition, seizures of unknown cause. These episodes are thought to be due to "mal-wiring" within the brain. Idiopathic epilepsy is seen in dogs between the ages of 6 months and 6 years of age. It is more common in certain breeds: border collies, Australian Shepherds, Labrador retrievers, beagles, Belgian Tervurens, collies and German shepherds. That being said, seizures can occur in any breed of dog or cat. To search for the cause of seizures, a systemic work up is performed (physical and neurologic exam, blood work, blood pressure, sometimes chest x-rays, specific liver function test including bile acid testing). Once an extra-cranial cause of seizures is ruled out, then the brain is imaged using either a CT scan or an MRI. Following brain imaging, a cerebrospinal fluid (CSF) tap is performed in order to look for encephalitis. If an underlying disease can be found, then primary treatment for that disease may help to make the seizures stop. If the seizures are recurrent, anticonvulsant medications are often given. The choice of medication depends upon the characteristics of the individual animal's problem. Some of the more commonly used anticonvulsants are listed below. It is important to remember that once an anticonvulsant is initiated, it should not be changed without veterinary assistance. Most animals with idiopathic epilepsy will require anticonvulsant medication for the rest of their life.

Drugs Used to Treat Seizures

• Phenobarbital is the most commonly used anticonvulsants in veterinary medicine because it is effective and also inexpensive. Side effects include: sedation, incoordination and rear limb weakness, , increased drinking, urination and appetite. With high dosages or prolonged use, phenobarbital can cause damage to the liver. Paradoxically, some animals given phenobarbital may become restless and excitable. If any of these signs are observed, occurs, consult your veterinarian for assistance. For best results, this drug needs to be given consistently (every day) at least twice daily. This drug should not be altered without veterinary consultation.
• Potassium Bromide is another effective first-line seizure medication used in veterinary medicine. Due to its lack of metabolism it is the ideal anticonvulsant for patients with liver disease. Side effects include: sedation, incoordination, limb weakness and vomiting. Pancreatitis has also been described as a possible complication. If any of these signs are observed, occurs, consult your veterinarian for assistance.
• Levetiracetam (Keppra) is a newer anti-convulsant for use in veterinary medicine. It is also not liver metabolized making it safe in patients with liver disease. It is to be given three times daily. Side effects are rare and include sedation and incoordination.
• Zonisamide (Zonegram) is a newer anti-convulsant for use in veterinary medicine. It, like phenobarbital, is metabolized by the liver. It is a sulfonamide medication and can therefore cause dry eye, decreases in white and red blood cells. It can also cause liver disease and sedation and incoordination.
• Diazepam (Valium) is a medication to be given on an emergency basis to halt an active seizure in dogs and cats because its effects are very short acting. Thus, this medication is not used on a daily basis. Side effects include drowsiness, lethargy, and depression and liver disease.

This information was made possible by funds from the Neurology Endowment at Washington State University.

It is essential for people to understand that assistance dogs, even in training, are not pets. They receive between one and two years of "basic" training exposing them to public places and then go on to "finishing" school for several more months to perfect their skills.

If you encounter a person with an assistance dog there are a few simple guidelines to follow:

• Do not touch or speak to the assistance dog. This is a distraction that interferes with their work and could endanger their human companion. 
• Never attempt to feed an assistance dog! Food is a significant distraction.
• Speak to the person, not the dog, if you have a question or would like information about their dog.
• If you feel compelled to help someone with an assistance dog, offer your assistance and wait for it to be accepted. Well meaning or not, assistance that is not sought is interference and can endanger both the handler and the dog.

Look at service dogs as you would any other hard working service provider, with respect for the job they are doing. 

This Pet Health Topic was written by Sarah Hoggan, Washington State University, Class of 2001.