Category: Handouts

What are the symptoms of old dog vestibular disease?

Many diseases can cause loss of balance, the most common being ear infection, a tumor in the brain or the inner ear, a vascular problem, toxicity to chronic drug administration (e.g., metronidazole), and old dog vestibular disease. Old dog vestibular disease is a condition with an acute onset of severe vestibular signs in an older dog. The clinical signs happen extremely rapidly, sometimes over a few minutes, and will cause severe incapacitation of the dog. It is not unusual for a dog to be unable to get up and walk because the loss of balance is so severe. Nystagmus is commonly seen. We assume that your dog feels dizzy and nauseous. Vomiting will sometimes occur. You may also notice that your dog will only lie on one side and will roll on the floor when attempting to move or when you try to turn him on to the other side.

What is the cause of old dog vestibular disease and how can it be diagnosed?

The cause of old dog vestibular disease is unknown. The diagnosis is made by the history (i.e., acute onset of loss of balance in an old dog), by the neurologic examination (i.e., no other neurologic signs, no weakness, and no signs of brain problem), and by ruling out other diseases (no sign of ear infection, tumor) The history is important in the diagnosis and it is important for you to try to recall any changes in your dog’s behavior or health in the previous days or weeks. Was your pet more depressed or lethargic lately? Did you notice more scratching of the ears or shaking of the head that could indicate ear infection? Did your pet seem to be getting old or dragging behind during walks recently? These can indicate that something more is going on. If there is a suspicion that something else is going on, your veterinarian might recommend further tests for your dog. Otherwise, only a good physical and neurologic examination is needed. Because it can be difficult to perform a complete neurologic examination the first day in a dog severely affected and obviously anxious, your veterinarian might recommend that your pet be hospitalized for the first few days or that you come back for a recheck examination after 1 to 3 days to complete the evaluation.

What is the treatment?

There is no specific treatment for old dog vestibular disease. Only time and supportive therapy is needed. If your dog seems nauseous or is vomiting, motion-sickness medication should be administered. Hospitalization and fluid administration might also be needed if the vomiting is pronounced.

Your dog will need help to walk and possibly even just to stand. It is easier to provide help by using a sling or a towel underneath the abdomen and a harness to support the front part of the body. Your dog will learn to use walls and your legs to help keep its balance. Try to avoid slippery surfaces!

In the event of a possible ear infection, it is wise to start antibiotic therapy. However, antibiotics are not needed for old dog vestibular disease.

Will my dog be normal again?

Although initial clinical signs are often dramatic, improvement is also dramatic. Your dog might improve as quickly as 2 to 3 days after the beginning of the problem. However, it will usually take weeks before your dog is almost back to normal. A complete recovery is expected; although in some dogs, a slight head tilt will persist for the rest of their life.

Relapses are not common but can sometimes occur.

Despite the severity of the clinical signs and the normal anxiety of your pet (and yourself!), the chance of recovery is excellent. All your dog needs is some time and your help.

1. The sympathetic nervous system
2. The endocrine system

The sympathetic nervous system acts through release of stress hormones such as norepinephrine and epinephrine, whereas the adrenal glands (organs in the endocrine system) release cortisol and a plethora of other steroids. FIC appears to be characterized by an exaggerated sympathetic nervous system and a blunted endocrine response to stressors that do not seem to affect healthy cats. Any treatment strategy to decrease sympathetic nervous system outflow may be important in reducing clinical signs. Reducing the noxiousness of the urine to the damaged bladder wall and normalizing bladder permeability may also prove useful.

What are the symptoms of lower urinary tract disease?

Symptoms of lower urinary tract disease in cats include variable combinations of the following:

• Frequent attempts to urinate
• Straining to urinate
• Urinating in inappropriate places in the house
• Crying out during attempts to urinate
• Blood tinged urine

These signs are not specific for any one disease; they can be seen in cats that have the following:

• Bladder stones (cystic calculi)
• Bacterial urinary tract infections
• Cancer
• Other mass lesions in the bladder

In fact, when clinicians are unable to find a specific cause for these symptoms, this syndrome is called idiopathic cystitis (FIC).

How is lower urinary tract disease diagnosed?

Before diagnosing FIC, your veterinarian may suggest some diagnostic tests to rule out the more defined causes for these symptoms. Because bladder stones are present in about 15% of cats with lower urinary tract (LUT) disease, an x-ray to check this possibility is a good place to start. The x-ray will also allow your veterinarian to see the entire LUT including the urethra, which is especially important in male cats. The two most common stones are calcium oxalate and struvite, which can be detected on radiographs. More specialized studies may be required to identify other, much less common stone types such as urate and cystine.

Although diet may play a role in stone formation in some cats, other factors that may contribute to the formation of cystic calculi include the cats’:

• Breed
• Age
• Sex
• Disease status
• Body condition
• Living environment

The many interacting variables demonstrate the complexity of the process of stone formation. If your veterinarian decides that your cat may have a stone, it is a good idea to obtain an x-ray to get a quick “stone check.”

In addition to an x-ray, a urine culture test for a bacterial urinary tract infection may be submitted, especially in cats with recurrent episodes of LUT signs. If a bacterial infection is diagnosed, appropriate antibiotics are prescribed and ideally, the urine should be re-cultured 3 to 4 days after cessation of the antibiotics to be sure the urine is sterile. If recurrent urinary infections are diagnosed, further diagnostics are warranted to evaluate the cat for underlying disorders, which might be predisposing him/her to these infections.

If radiographs (and other imaging studies) are negative, it is likely the cause for the cat’s clinical signs will not be determined, especially if the cat is young (younger than 8 years). If signs are persistent, severe, recur often, or if the cat is older than 10 years, an examination of the bladder surface using a small “telescope” (cystoscopy) may be warranted. This procedure, which is done under general anesthesia, allows one to visualize the urethra, ureteral openings, and bladder with a small scope. Tiny stones, polyps, tumors, and other abnormalities can be seen, which may have been difficult to evaluate with other imaging studies. If no underlying cause can be found for the LUT signs, the diagnosis of FIC is confirmed.

What treatment is needed?

The underlying causes of FIC are incompletely understood, so current treatment recommendations must necessarily be tentative. The current goals of therapy for cats with FIC are to decrease the severity of their symptoms and to increase their symptom-free period, especially for the severely affected cats. Furthermore, this disorder does not appear to be restricted solely to the bladder, so the “entire cat” should be evaluated and other identified problems addressed. Based on the abnormalities that have been documented in this disease, we have developed some treatment guidelines that may be helpful.

From what we have observed in cats with this disorder, it appears to be a painful condition. During an acute episode, pain relief therapy may be prescribed. A mild sedative may also be beneficial to decrease the anxiety that can be seen during acute flare-ups. This therapy is generally prescribed for 2 to 3 days. One should pay close attention to make sure that at least small amounts of urine are passed, especially in male cats.

If a stone is found, surgery may be the only option for stone removal. If “sand and debris” or even very small stones (3 to 5 mm) are found in the urinary bladder, surgery may not be necessary. A technique called urohydropropulsion (infusing saline into the bladder and flushing the stones out throughout through the urethra under heavy sedation or anesthesia) may be used to remove the sand or small stones. All stones should be submitted for quantitative analysis. Once the stone is removed, your cat should be monitored every 2 to 3 months for recurrence until the danger of another stone is past.

Canned food may be preferable for cats with FIC because the increased water content in canned food may dilute potential noxious components in the urine, which may decrease the pain associated with this disorder. Offering choices of canned and dry food in separate, adjacent containers rather than replacing the usual food with a new food permits cats to express their favorites. If cats will not eat canned food, other preferences for water should be investigated. Consideration may be given to freshness, taste, movement (water fountains, dripping faucets, or aquarium pump-bubbled air into a bowl), and shape of container (some cats seem to dislike having their whiskers touch the sides of the container when drinking). Food and water bowls should be cleaned regularly unless individual preference suggests otherwise.

The environment should be addressed with the premise that providing an “enriched” environment for these cats will help to decrease the sympathetic “overdrive” and prolong the inter-episode interval. Litter boxes should be cleaned regularly and placed in a quiet, easily accessible area of the house. More than one litter is suggested. Litter should be unscented. Litter box size and type (open or covered) also may be important to some cats.

Cats interact with both the physical structure and other animals, including humans, in their environment. The physical environment should include opportunities for climbing, scratching, hiding, and resting. Because cats are not pack animals, cats residing in multi-cat households should have their own area to “escape” from one another. Some cats may even prefer to have their own separate food and water sources, litter box, and resting areas to avoid competition. This permits them to avoid unwanted interactions. Playing a radio to habituate cats to sudden changes in sound and human voices and to provide visual stimulation may also be helpful. More information about environmental therapy for cats is available at www.nssvet.org/ici.

Once environmental strategies have been employed, it still may be necessary to utilize other therapeutic approaches such as pheromone or drug therapy. Pheromones are natural substances produced by cats. They seem to transmit highly specific information between animals of the same species. Feliway (Ceva Sante Animale, Libourne, France) is a synthetic analogue of a fraction of a naturally occurring feline facial pheromone. It was developed in an effort to decrease anxiety-related behaviors of cats. Although not specifically testing in cats with FIC, the anti-anxiety properties of this pheromone may be beneficial, especially in multi-cat households.

Many drugs have been used to treat cats with FIC, although none have been consistently successful for long-term resolution of symptoms.

Some of these medications include the following:

• Analgesics
• Tricyclic and other antidepressants
• Non-benzodiazepine anxyiolytic drugs
• Glycosominoglycan replacers (to improve the lining of the bladder wall)
• Antibiotics, in the case of bacterial infection

Some of these drugs can be of benefit for severe, recurrent FIC. No drugs should be used without a structured environmental strategy as well. Furthermore, these drugs (except pain killers) should never be used to treat acute episodes. Cats should be monitored closely during therapy.

If your cat was diagnosed as having a stone or stones, the best way to reduce the risk of another stone is to feed a prescribed canned diet to make your cat’s urine “clear, colorless, and odorless.” This will decrease the urine concentration of the mineral precursors that stones form from. Offering the new diet in a separate dish next to the cat’s usual food will increase the chances of your cat making the switch to the new food within a few days. When the cat starts eating the new food, the amount of the previous diet may be slowly decreased until the cat is only eating the new food. If your cat will not accept the new diet, water intake can be increased by the use of drinking fountains, or by adding flavorings (ham, tuna) to the cat’s water, either as liquids or made into ice cubes. Other treatment regimens for specific stone types can be provided by your veterinarian.

What is the prognosis?

Most cats with FIC are young to middle aged. Symptoms resolve spontaneously in as many as 85% of cats within 2 to 3 days, with or without treatment. Within 12 months, as many as 50% of these cats will have another episode. It is not yet possible to predict which cats with FIC will relapse; some cats have multiple recurrences, whereas clinical signs never resolve in a small population of severely affected cats.

The primary function of thyroid hormone is control of the rate that cells function:

• Too much thyroid hormone makes cells work too fast. Low thyroid function (hypothyroidism) is relatively common in dogs and quite rare in cats.
• Too little thyroid hormone causes cells to work too slowly. Excess thyroid function (hyperthyroidism) is rare in dogs but is one of the more common diseases diagnosed in cats that are 8 years of age or older.

It is not known exactly why cats develop hyperthyroidism:

• About 15% of hyperthyroid cats have a single thyroid tumor in one of the two lobes, called an adenoma (not a cancerous tumor) that produces too much thyroid hormone.
• About 80% of hyperthyroid cats have abnormalities in both thyroid lobes with both lobes producing excess thyroid hormone. These cats also have a benign (noncancerous) condition called adenomatous hyperplasia.
• Only about 3% of hyperthyroid cats have a malignant (cancerous) thyroid tumor.

Regardless of the description that a pathologist may provide regarding the thyroid from a cat with this condition, the final common denominator for each cat is the excess in thyroid hormone in the system that usually affects virtually every cell and every organ in the body. The organ systems that become overactive as a result of this exposure cause symptoms to vary somewhat from cat to cat. In general, hyperthyroid cats typically have their condition for some time (usually months) before an owner observes worrisome symptoms.

What are the symptoms of hyperthyroidism?

Each cat responds to his or her hyperthyroidism a little differently, causing observed abnormalities to vary from cat to cat. Among the most common owner observations are the following:

• Weight loss
• Increase in appetite
• Patchy hair loss or failure to groom (some cats have been observed to pull their hair out)
• Increase in water intake
• Increase in urine output
• Increase in activity level (some cats are persistently restless or nervous)

Some hyperthyroid cats have a change in behavior and when this happens, they tend to become irritable, mean, or easily upset. Vomiting and diarrhea are a little less common. Some hyperthyroid cats have unusually bulky stools and others have unusually large amounts of stool. Relatively uncommon but well-documented problems caused by hyperthyroidism include panting (open mouth breathing), difficulty breathing, loss of appetite, muscle weakness, listlessness, and seeking cool places.

What tests are needed?

The diagnosis of hyperthyroidism, regardless of the underlying changes within the thyroid gland itself, is relatively easy in most cats. Most hyperthyroid cats have too much thyroid hormone (thyroxine, or T4) in their blood all the time. This can be confirmed with a simple and relatively inexpensive blood test measuring T4. A small percentage of hyperthyroid cats do not have a “diagnostic” blood T4 concentration and, in this situation, your veterinarian may wish to repeat the test a few days, weeks, or months later.

Your veterinarian may elect to use a different thyroid blood test (called the “free T4 test”) or their recommendation may be to have a thyroid scan performed on your cat. All these options are excellent and each one tends to complement the others. Virtually any veterinary can run the T4 and free T4 tests. Thyroid scans, however, require special facilities and usually require referral to a hospital with this equipment. Regardless, if your veterinarian believes your cat has this condition, the diagnosis is usually straightforward and relatively inexpensive.

Because hyperthyroid cats tend to be older, because they tend to have worrisome symptoms consistent with various non-thyroid-related diseases, and knowing that excesses in thyroid hormone can have deleterious effects on various organ systems, your veterinarian will likely recommend tests in addition to those which identify the thyroid status of your pet.

Some of these additional tests may include the following:

• CBC (complete blood count), to assess the red and white blood cells
• Chemistry panel and UA (urinalysis), to assess the function of various organs
• X-rays of the chest, to rule out congestive heart failure (a possible complication of hyperthyroidism) and other thoracic problems (not associated with the disease)
• X-rays or ultrasonography of the abdomen, to assess the various abdominal organs.

What treatment is needed?

Treatment, no treatment, and your cat’s kidneys. Hyperthyroid cats that are not treated usually become progressively more ill. They tend to be quite thin, weak, and are likely to develop life-threatening problems. If your cat is not symptomatic, there should be no rush to treatment. In contrast, delaying treatment for symptomatic cats is unreasonable. Three commonly used treatments are available for managing hyperthyroidism in cats. Each treatment has the potential to provide excellent results and each has both advantages and disadvantages. Your veterinarian will explain the choices to you and help you decide which option may be best for you and your cat. Treating your cat will usually either return it to a reasonable state of good health or permanently cure the cat of this disease.

One fascinating aspect of treating hyperthyroidism in cats is that resolution of this condition is almost always associated with reduction of the blood supply to kidneys. In most cats, this is not worrisome. However, reducing the blood supply to the kidneys of some cats leads to compromise of their kidney functions, which is more worrisome and dangerous than hyperthyroidism. Therefore, if kidney disease is suspected in your untreated cat or if your veterinarian has other reasons to be cautious, trial therapy with methimazole may be recommended prior to using a more permanent form of treatment.

Methimazole. Methimazole is an oral (pill) medication that works by blocking the production of thyroid hormone. The effects of this drug are completely reversible. If you stop giving this drug, most cats quickly return to the same thyroid condition they had prior to using the medication. Thus if correcting the hyperthyroidism causes kidney results to become worrisome, then the medication can be discontinued or tailored to a dose that may not completely resolve the hyperthyroidism but also may not harm the kidneys. The drug is readily available and not terribly expensive. The major attribute of this drug is its ability to consistently decrease thyroid function. It is effective in virtually every cat. The drug usually works best when given twice daily.

Because this medication has potential side effects, starting out with an extremely low dose and slowly increasing the dose to effect is safest and most effective. Some veterinarians start with 2.5 once daily for 2 weeks, a dose that is too low to resolve the hyperthyroidism but one that rarely causes side effects. However, just getting a little drug into cats tends to minimize side effects as the dose is increased to achieve desired blood test and clinical responses. Therefore, as needed, they increase first to 2.5 mg twice daily for two weeks, check the blood, and then increase by 2.5 mg per day at 2-week intervals.

The major negative aspect of methimazole is that some cats are not the best pill takers. Rather than fight these cats, methimazole can be “compounded” by some pharmacists into a topical cream. The owner then uses a latex glove or finger cover, places the correct dose on his or her finger, and rubs the medication (usually in a tiny amount of cream) into the inner aspect of one ear. The medication needs to be rubbed in well (usually for 30 to 120 seconds) and then about 20 minutes later any excess cream (if there is any left) should be cleaned away with cotton and warm water.

Medication compounded by a good pharmacist is at least as good; frequently more effective in this route than it is when given orally. Because it is sometimes more effective, some veterinarians use a lower dose to start: usually 1 or 2 mg once daily and then increased as needed.

Other negatives about methimazole, especially when given orally, are that it causes some cats to lose their appetites or vomit. These side effects are much less common in cats given topical rather than oral medication. Even less common, but more worrisome, side effects include liver damage and decreases in red blood cells, white blood cells, and platelets. Platelets help blood to clot so loss of platelets can cause bleeding, whereas loss of white blood cells predisposes these cats to infection, and loss of red cells is anemia that can make a cat weak or die. Rarely, treated cats develop a type of reaction and they begin to scratch their faces uncontrollably.

Although many of these side effects are alarming, they are not common. Therefore this drug is given to virtually every hyperthyroid cat. It is either their only means of treatment or it is given to test the effects of resolving the increased thyroid hormone concentrations on kidney function prior to using a permanent form of therapy.

Surgery. Surgery can be used to remove the abnormal thyroid lobe or lobes. The benefits to this surgery include the following:

• It is not difficult
• It does not require fancy equipment
• Is not terribly expensive
• It has the potential to resolve the hyperthyroidism quickly and permanently

Most veterinarians either do this surgery or can refer you to a colleague who does it. The negatives associated with this surgery are that it does require anesthesia. Because many hyperthyroid cats are older and afflicted with other problems that could complicate surgery, this treatment is not always an option. However, the anesthesia is relatively brief and it is an extremely effective means of managing this condition.

Radioactive iodine. The third treatment option is the use of radioactive iodine. Iodine is one of the primary ingredients of thyroid hormone. Iodine that is radioactive is trapped and taken up by the thyroid lobes just like any other iodine. However, the radioactivity in this medical-iodine destroys surrounding thyroid cells and can permanently resolve hyperthyroidism.

The benefits of this treatment include the following:

• It is an extremely effective form of treatment
• It resolves hyperthyroidism quickly
• It requires no anesthesia
• No pills are necessary
• Like surgery or methimazole, it almost never causes hypothyroidism

The negative aspects of this form of treatment are that sophisticated facilities licensed for use of radioactive materials are required. Although this treatment is not available everywhere, it is available in numerous sites throughout the United States and more treatment centers continue to open. It tends to be more expensive than surgery annually, in part because treated cats must remain hospitalized until their body levels of radioactivity are safe. This allows all urine and stool (which contain radioactivity) to be properly disposed. Hospitalization usually ranges from several days to as long as 2 weeks.

Human beings, dogs, cats, and almost all other species of animals naturally have cortisone in their blood and in every tissue of their bodies. This cortisone is produced by a small pair of glands called the adrenal glands, one located near each kidney. In appropriate quantities, cortisone is necessary for health. If an individual (person, dog, or cat) does not have enough cortisone, they usually become ill and can eventually die. Too much cortisone in the system (Cushing’s syndrome) also causes illness, although it does not cause the type of sudden death that often results from not having enough cortisone.Dr. Harvey Cushing was a physician who practiced medicine in the 1920s and 1930s. He had many areas of expertise; among these was pathology. It was in his capacity as a pathologist that he wrote a paper describing a group of people, each of whom had died from an apparently similar cause. Each person had become ill and then died after what is now understood to be the consequences of having too much cortisone in their systems over a long period of time. Respecting his discovery, the term Cushing’s syndrome was applied to the clinical condition that results from chronically having excess cortisone in the system. As Dr. Cushing’s observations became known to physicians, they also became known to veterinarians. This problem (Cushing’s syndrome) has since been identified in a variety of animal species, including dogs and cats.

What causes too much cortisone in the system?

Too much cortisone in the body can occur because your pet was given cortisone in excess. Cortisone containing drugs include, but are not limited to the following:

• Prednisone
• Prednisolone
• Methylprednisolone
• Triamcinolone
• Dexamethasone

Regardless of whether it is given by injection, pill, or a steroid-containing topical skin cream or eye medication, cortisone has specific effects that dictate the diseases for which they are used. Development of Cushing’s syndrome means that your pet has received too much cortisone but does not indicate that your veterinarian gave too much cortisone by mistake. Rather, cortisone is an important and common drug that commonly causes side effects. That form of Cushing’s syndrome, the one caused by your pet receiving excess cortisone, is simply treated by discontinuing your pet’s exposure to such medication.

When Cushing’s syndrome occurs naturally, the changes (abnormalities) that take place internally, as well as the external symptoms, can be identical to those secondary to your pet being given too much cortisone-containing drugs. The final common denominator in Cushing’s syndrome is too much cortisone in the body, whether it occurs naturally or as a result of medical treatment. The natural form of Cushing’s syndrome in dogs and cats represents a relatively common problem in older dogs but is quite uncommon in cats. A small percentage of dogs and cats (~15%) with naturally occurring Cushing’s syndrome have a tumor in one of their two adrenal glands. The tumor persistently produced cortisone in excess and eventually causes “Cushing’s syndrome.”

Most dogs and cats with naturally occurring cortisone excess (85% to 90%) have a small tumor located in an area at the bottom of the brain called the pituitary gland. Animals and humans with this problem have tumors that persistently send a message to the adrenal glands “asking” for cortisone production and release into the circulation. The message being sent is in the form of a protein placed into the blood stream and delivered to the adrenal glands.

This message (called “ACTH”):

• Is produced in excess
• Does not turn off
• Causes both adrenal glands to grow
• Causes cortisone to be produced excessively, without abatement
• Results in the development of Cushing’s syndrome

What are the symptoms of Cushing’s syndrome?

Chronic excesses of cortisone in the system of dogs can result in a variety of symptoms. Not all dogs have the same symptoms but most have at least two or three of the more commonly observed abnormalities.

These more commonly observed symptoms include the following:

1. Development of profound excesses in urine volume. Many of these dogs urinate for longer time periods than normal or they urinate more frequently. Some produce so much urine that there is leakage when the pet sleeps. Many previously “housebroken” pets begin urinating indoors. In concert with the production of excess urine is excess thirst, which is usually not as worrisome to pet owners as the urination problem.
2. Loss of hair with no regrowth, whether hair simply falls out or is shaven. Hair loss is most commonly observed along the back, tail, and the back of the rear legs. Hair loss can result in a thin hair coat or it can cause complete hair loss and a bald appearance. Dogs with Cushing’s almost never lose the hair from their heads or their feet.
3. Development of muscle weakness. This may be seen as a dog having trouble climbing stairs or difficulty jumping onto furniture or into a car. Muscle weakness may cause these dogs to be unable to go for long walks without simply “running out of gas.” It can also cause dogs to have difficulty rising after they have been sitting or lying down. Muscle weakness may also cause a “pot-belly” appearance to the abdomen.

Dogs with Cushing’s syndrome virtually always have an excellent appetite and some are abnormally ravenous for food. In contrast, these dogs rarely have problems with vomiting or diarrhea. They do, however, often pant excessively.

What tests are needed?

In addition to owner-observed abnormalities, veterinarians may detect additional problems. Veterinarians may observe the following:

• Thin skin
• Skin infections
• Muscle atrophy
• Large liver on abdominal palpation

Routine blood and urine testing often reveals various abnormalities. The urine from dogs with Cushing’s syndrome is often dilute and infections of the urinary tract are common. Abnormal liver test results are common, especially in those dogs that also have an enlarged liver. Despite these potentially worrisome liver test results, dogs with Cushing’s syndrome do not have a “sick” liver and these dogs almost never become ill or die from liver problems. Dogs with Cushing’s syndrome do have high blood cholesterol concentrations and they also commonly have high blood pressure.

Veterinarians usually recommend taking radiographs of the chest because dogs with Cushing’s syndrome are often older and it is important to be certain that such dogs do not have unexpected abnormalities in or near their lungs.

Either radiographs or ultrasound of the abdomen are recommended for several reasons:

1. About 50% of adrenal tumors can be seen on radiographs of the abdomen and more than 90% of adrenal tumors can be visualized with ultrasonography.
2. Adrenal glands in dogs with the pituitary form of Cushing’s undergoing ultrasound examination are either normal (~50% of the time) or enlarged (~50% of the time).
3. Abdominal examination with either tool (radiographs or ultrasonography) is also used to assess this body cavity for both expected (big liver, fat accumulation) and unexpected problems.

Once this “battery” type of testing has been completed, assuming that your veterinarian still suspects that your pet has Cushing’s syndrome, specific hormone testing to “confirm” this diagnosis is usually recommended. The tests usually used are the ACTH stimulation test, the urine cortisol creatinine test, and the low dose dexamethasone test (LDDST). Each of these tests is common and relatively effective. Each has advantages and disadvantages. Further, depending on these results and those of abdominal ultrasonography, tests may be recommended that aid is discriminating dogs with the pituitary form of the disease from those with an adrenal tumor.

What treatment is needed?

Two common questions asked are the following: “Do I really need to treat my dog?” and “What if I don’t treat my dog?” The answer to the first question is one that only an owner can decide. However, untreated dogs do tend to be weak, abnormally addicted to food and water, and generally not happy, playful, or active. If you, the owner, do not see any abnormalities in your dog and you believe that your pet is well, treatment is not recommended. Untreated dogs with true Cushing’s syndrome are not seen as being healthy by their owners. Treated dogs can become quite normal and for this reason, correction of this condition is usually suggested.

Based on test results, your veterinarian may recommend surgery or oral drugs to attempt to treat the natural form of Cushing’s syndrome. The surgery is not easy and is often best attempted by a specialist. Oral treatment involves use of potentially toxic agents. However, successfully managed dogs, regardless of the recognized treatment chosen, far exceed the treatment failures. Owners therefore are encouraged to consider treating their pets.

Diabetes mellitus is extremely common. It is estimated that 1 in every 19 Americans has the condition and although less common in dogs and cats, it remains a frequent diagnosis. As previously stated, the key that gives cells access to sugar is insulin, a protein created by specialized cells scattered throughout the pancreas. The pancreas, an organ with several important jobs, is located in the abdomen next to the stomach. Insulin from the pancreas is pumped into the blood stream and distributed to cells throughout the body. If the pancreas fails to produce enough insulin, cells no longer have the needed key for using sugar.

Specialized cells in the brain control appetite. Those cells, like all the others, need sugar via insulin to function. When these brain cells begin to “starve” without sugar, they produce a signal demanding that the individual eat more to supply them with energy. However, the problem is not that crude energy is failing to be consumed. Nor is the problem that this crude energy is failing to be refined into sugar. Therefore regardless of the increase in appetite to try and supply the much-needed sugar, no key (insulin) allows cells access to sugar. Although cells in the brain are demanding that more and more food be consumed, other cells in the body respond to their “starvation” by demanding that fat and muscle in the body be broken down. The breakdown of muscle and fat usually causes obvious weight loss. Breakdown products of fat and muscle can be converted to sugar by the liver. This sugar could supply the energy needs of cells. Once again, regardless of the source of crude energy and sugar (through eating or through breakdown of fat and muscle), the key that would allow use of this energy source is missing.

If the sugar being refined from ingested food and from breakdown of fat and muscle is not taken up by cells for energy, it begins to accumulate in the blood stream. So, the tank is being filled, but the “gasoline” being pumped into the tank is not being used. When too much sugar is pumped into the tank (sugar accumulates in the blood), it begins to overflow or “leak” into the urine. Urine of healthy individuals never contains sugar. Sugar cannot appear in the urine by itself. Rather, sugar draws water into the urine just like a dry sponge draws water. Therefore the individual with sugar in the urine produces large urine volumes because of the water being excreted as well. This process can eventually create tremendous water losses. In response to this excess urine volume, individuals with sugar in their urine begin to drink excessively in an effort to maintain water balance (hydration). These responses to the simple lack of insulin are natural and instinctive. They are unavoidable. All individuals (people, dogs, cats, etc.) with an insulin deficiency (diabetes mellitus) have the same symptoms: they all eat excessively, they all lose weight, they all drink excessively, and they all urinate excessively.

Two common forms of diabetes mellitus exist in people. Some people with diabetes have absolutely no insulin. The most common names used for this form of diabetes mellitus are: insulin-dependent diabetes mellitus (IDDM), type I diabetes, and “juvenile-type” diabetes. People with type I diabetes mellitus require insulin therapy (usually by injection) to survive. The second form occurs when an individual has some insulin but either does not have enough insulin to supply all cells when it is needed or they have a condition that interferes with insulin action (the key no longer fits into the ignition). This form also has several names. The most common names are: non–insulin-dependent diabetes mellitus (NIDDM), type II diabetes, and adult-onset diabetes. Approximately 60% of diabetic cats have type I disease and 40% have type II. Virtually 100% of diabetic dogs have type I disease. Although changes in diet, weight loss, exercise, and oral drugs can be used successfully in managing many people with type II disease, insulin administered by injection remains the best treatment for all dogs and cats diagnosed as having diabetes mellitus.

What testing is needed?

The diagnosis of diabetes mellitus is usually extremely straightforward. Your veterinarian probably became suspicious of diabetes mellitus because you (the owner) noticed that your pet exhibited some or all of the following symptoms: weight loss and/or excessive urination, drinking, or eating. The diagnosis is confirmed with finding sugar in the urine and an abnormally increased blood sugar concentration. However, despite this relatively simple diagnosis, your veterinarian will likely recommend additional tests. These additional tests are warranted because most diabetic dogs and cats are middle aged or older and most have other medical problems. Those conditions seen most commonly among diabetics include urinary tract infections, skin infections, and an irritated pancreas (pancreatitis). Heart disease, kidney disease, and anemia are just a few of the non-diabetic diseases sometimes seen in these pets. So, additional blood and urine tests, radiographs of the thorax, and ultrasonography or radiographs of the abdomen are tests well worth the investment.

What treatment is needed?

Can diabetes be cured? It is extremely rare for a dog with diabetes to be cured. In only two situations is there even a chance of a cure: dogs pregnant at the time of diagnosis and dogs with a condition called Cushing’s syndrome. Most of these dogs, however, are not cured of their diabetes even with appropriate care. In total, far less than 1% of dogs with diabetes mellitus have their disease state resolve. The incidence of “cure” is a bit higher in diabetic cats. An estimated 10% to 40% of diabetic cats have their disease resolve sometime during the 12 months following diagnosis. In either dogs or cats, the most important factor in having diabetes resolve is luck.

Can my pet be treated with pills rather than with injections? Unfortunately, insulin is almost always given by injection, especially to dogs and cats. Dogs with diabetes mellitus virtually never respond to oral diabetes treatments. Oral medication, as the sole treatment for diabetes, should not be given to diabetic dogs, even on a trial basis. During such a treatment trial, your pet might become extremely ill. This is less likely if insulin were used. A small percentage of diabetic cats respond to oral hypoglycemic medications that are used for humans. The only drugs established as potentially effective in cats are called glipizide and glyburide. Despite their potential for success in some cats, the recommendation is to treat all diabetic cats with insulin. The only reasons for using oral medications in cats are the following: (1) an owner who refuses to give insulin and who is considering euthanasia rather than giving their cat injections and (2) the insulin-treated diabetic cat that seems to require extremely small doses (one unit per dose once or twice daily) to maintain control.

Insulin Therapy. The most important concept to remember is that most diabetic dogs and cats treated with insulin lead healthy and happy lives. Unfortunately, although insulin has been used to treat people that have diabetes mellitus for more than 80 years, it must still be given by injection. The other, and much bigger disappointment, is that despite tremendous amounts of experience in treating diabetic dogs and cats, veterinarians understand that no precise dose of insulin exists as determined by body weight, gender, breed, or any other parameter. Further, several types of insulin are available through veterinary and human pharmaceutical companies. No particular insulin is “perfect” for every dog or cat. Owners of all diabetic dogs and cats must understand that the treatment of diabetes represents a continuing course of trial and error.

Your veterinarian will recommend a type of insulin (e.g., NPH [N], Lente [L], Ultralente [U], glargine, or PZI) and an origin (e.g., Humulin [human], or porcine [pig]). Your veterinarian will also recommend a dose and frequency of administration (once or twice daily). Although most diabetic pets seem best controlled when receiving insulin given twice daily, once daily injections may work and once daily regimens are often used initially just to have owners become familiar with the process. Then, if needed, the second injection each day can be recommended. All these choices will be explained to you. They are usually made on the basis of previous experience managing other diabetic dogs and cats. The goal here is not easily achieved: to choose the correct insulin, dose, and frequency of administration. It is always safe to assume that the first regimen chosen may not be as effective as you might like. With trial and error adjustments, however, a treatment protocol can typically be established that will provide your pet with a happy and almost normal existence. Owners should try to be as patient as possible because nature is not easily predicted. Achieving success in the management of a diabetic requires three key ingredients: a skilled veterinarian, a committed owner, and luck. If you do begin to give insulin twice daily, do not think that the timing needs to be exact. Rather, giving insulin at convenient times is fine and if these times vary by 30, 60, or even 90 minutes each day, your pet will be fine.

Handling Insulin and Injection Technique. Giving your pet injections is an intimidating prospect for most owners and there is no doubt that dogs and cats can feel the needles. Once you do this for a few weeks, you will become competent and your pet will accept the tiny pin pricks. Don’t give up! Dogs and cats do learn to accept this treatment without changes in behavior or personality. Owners should remember a serious and important truth: the single most common cause for a diabetic dog or cat to appear “insulin-non-responsive” and to remain symptomatic is owner error. Mistakes in handling or injection of insulin are unfortunate but fact. Therefore owners must remember numerous bits of information to avoid mistakes.

First, store insulin on the door of your refrigerator right side up. Insulin should not be left at room temperature for prolonged time periods because it might lose potency. If the insulin freezes, you should obtain a new bottle. Prior to removing insulin for each and every dose, the insulin should be mixed. This is best accomplished by making a fist around the bottle and then slowly rotating your wrist back and forth a few times. You will be taught how to draw insulin into a new unused syringe for each injection by first pulling back on the syringe plunger to the dose, turning the bottle completely upside down, placing the needle into the center of the stopper, injecting the air in your syringe into the bottle to avoid creating a vacuum, and then drawing the correct amount into the syringe. While the syringe needle is still in the upside-down bottle, tap the syringe to force any bubbles or air to the top, squirt those back into the bottle and again draw out the insulin to the correct dose. Then remove the needle from the bottle.

Finally, you will learn how to give an injection. Most owners gently pinch a small amount of skin with the thumb and index finger of one hand behind your pets’ neck or somewhere along their back. The needle target is NOT between your fingers rather it is in the hollow you have made just below your fingers. Place the needle at a 45-degree angle through the skin below your finger tips and push the needle in as far as it will go (these needles are usually quite short). Remember do not place your thumb on the plunger during needle insertion. Once the needle is fully inserted through the skin, move your thumb to the plunger and press the plunger all the way down. Once you have pushed the plunger all the way down, pull the needle out of the skin.

Alcohol application to the skin prior to injection is not recommended. First, you will not really “sterilize” the skin. More importantly, if the skin starts out dry, you can know immediately that an error has been made if the skin is wet after injection.

Several excellent web sites provide instructions for insulin administration, photographs, and videos. One source is the link through a veterinary company called Intervet.

Feeding. The ideal body weight for a diabetic pet is simply one that is normal. Therefore if your pet is too thin, weight gain is important and if your pet is overweight, weight loss will improve insulin effectiveness. Most veterinarians recommend twice daily feeding of diabetic pets. Feeding more frequently is fine (three or more times each day or all day as in cats accustomed to “grazing”). If your pet eats at specific times, it is ideal to feed first, wait until your pet has consumed the meal, and then administer insulin. Because insulin works by allowing cells to utilize sugar, it is important for that insulin to have sugar present. Administering insulin to a pet that then refuses to eat means that the pet is now predisposed to developing a blood sugar level that might be too low or dangerously low. If a pet has many meals through the course of a day, that concern would not be as serious.

Much current research is focusing on determining the best food for diabetic pets. Research has resulted in several pet food companies producing specific diabetes diets. Each of these commercially available diabetes diets is different in some minor or major way. It is currently recommended that you follow the advice of your veterinarian regarding diet with one important overriding factor being kept in mind: the most important attribute of any diet is your pet’s willingness to eat that food. A diet is only useful if your pet readily and consistently eats it. That being appreciated, some researchers believe that fiber is of benefit to diabetic pets. However, there are various forms of fiber and the one most likely to be of benefit to your pet can be determined by your veterinarian. Other research has suggested that diets with particular percentages of protein, fat, or carbohydrate can be beneficial. Again, your veterinarian’s opinion here is critical, because the diet for one diabetic may not be best for another. Your veterinarian knows all the confirmed and suspected problems in your pet. Those conditions may alter diet choices. For example: one might not want to offer a diet high in fat to a pet that has had pancreatitis, but it may be ideal for another diabetic.

Insulin Underdose. If your pet is underdosed with insulin, symptoms of diabetes tend to persist. Therefore if your pet continues to exhibit excesses in hunger, thirst, and urine volume as well as continuing weight loss, one likely explanation is under dosage. Understand that an underdose may occur because your pet simply needs more insulin. However, underdosage also can be caused by using insulin that turns out to be less than ideal for your pet. The most common cause of underdosage is that the person giving the insulin is doing something incorrect. Therefore whenever the owner brings their diabetic pet to the veterinarian, trained personnel should watch the entire owner-injection process to ensure mistakes are not being made.

Insulin Overdose. An overdose of insulin causes the blood sugar concentration to decrease too far. This can cause a variety of different problems. Possible observations include profound weakness; the pet may appear drunk or even have a seizure. If low blood glucose is ever suspected, it is best to feed your dog or cat immediately. Do not take your pet to the hospital because the delay may make the condition worse.

If your pet loses consciousness:

1)      Be certain your pet is not in danger of being hurt (near the edge of a deck or the edge of a swimming pool, for example)

2)      Glance at a clock and note the exact time (diabetic seizures usually last 30 to 90 seconds) and if the episode lasts longer than 5 minutes, veterinary care should be sought

3a) Place Karo syrup (either light or dark Karo syrup) in a syringe (this syringe will be larger than your insulin syringe and will be given to you by your veterinarian) and then squirt small amounts (2 to 5 cc) into the pets’ mouth every 5 to 10 seconds        or

3b) Place Karo syrup on your fingertips and rub the syrup inside the lips (NEVER place your fingers further inside the mouth as you are at risk for being bitten by an unconscious pet)

Other symptoms of overdosage can be confusing. Some overdosed dogs and cats simply sleep more. Some overdosed dogs and cats act as if they are underdosed! This common occurrence is the result of low blood glucose triggering glucose to rebound to levels well above normal. The increased blood glucose in this situation can persist for several days. Why does an overdosage occur? Understand that an overdose may occur because your pet simply needs less insulin. However, overdosage also can be caused by using insulin that turns out to be less than ideal for your pet. The most common cause of overdosage is that the person giving the insulin is doing something incorrect. Therefore whenever the owner brings their diabetic pet to the veterinarian, trained personnel should watch the entire injection process to ensure that mistakes are not being made.

What Should Be Done if an Insulin Dose Is Missed or if a Mistake Is Made During an Injection? Sometimes someone may forget to give insulin. Other common occurrences include your pet moving suddenly during an injection or you simply make a mistake and are not certain if your pet received the correct dose of insulin, if your pet received no insulin, or if your pet received a portion but not all of the dose. None of these situations should be unduly worrisome. The correct response to any of these occurrences is to simply give the correct dose of insulin when it is next scheduled. If an entire dose is missed, your pet will be fine. However, if a portion of a dose was given and then you give another dose immediately, there is risk of overdosage. A missed dose or an underdose is always preferred to an overdose.

Monitoring Insulin Therapy. Numerous methods of monitoring diabetic dogs and cats exist to better improve chances of a successful outcome. No one method is better than another and most complement each other. The most important tool in determining if your pet is responding to therapy appropriately is your (the owners’) opinion. The goal of treating a diabetic dog or cat is to have an owner be pleased with their pets’ response. It is not reasonable to expect your pet to be 100% normal in all aspects, but it is reasonable to have your pet be comfortable, interactive, and relatively healthy. Most diabetic pets urinate more than normal and most maintain an excellent (ravenous?) appetite. Weight loss should not be a problem. Your veterinarian may recommend certain tests periodically. These include checking the blood sugar concentrations throughout the day either in the hospital or you may wish to attempt to do this yourself at home. Veterinarians may want you to check the urine of your pet periodically (each morning, for example) for sugar and something called ketones. Finally, some blood tests tell the veterinarian what the average blood sugar level has been for the previous few days. Each of these tests should complement watching you administer insulin and your opinion regarding response to treatment.

Urine Monitoring. Many veterinarians like to have owners of diabetic dogs check the dogs’ urine daily for sugar and ketones. Sugar levels in urine of well-controlled diabetic pets tend to fluctuate dramatically day to day. Ketones, however, should always be negative. If sugar levels are constantly at their highest level, poor control is likely. If ketones appear after weeks or months of being negative, one should be concerned. This may indicate that your pet has a serious problem and your veterinarian should be notified.

Cataracts. Almost all diabetic dogs become blind within the first year after diagnosis. Blindness is due to development of cataracts in the lens (in the center of the eye). Cataracts are opaque and do not allow light from the outside to enter the back of the eye for vision. This side effect of diabetes is virtually unavoidable. Blind dogs do quite well, especially indoors in a familiar environment. Cataracts can be surgically removed to restore sight in most dogs. Some dogs will be blind even if cataracts are removed and others have cataracts that cannot be removed.

What Should Be Done if the Urine is Positive for Ketones or if My Pet Refuses to Eat or if My Pet Begins to Vomit? Any of these abnormalities are reason for concern. The best advice to follow if any of these situations are encountered is to contact your veterinarian or immediately take your pet to your veterinarian or to a local veterinary emergency clinic. It is better to bring your pet to the veterinarian unnecessarily than to ignore a serous complication.

Conclusion

Treating a dog or cat for diabetes mellitus can be challenging but it can also be extremely rewarding. Most of these pets are happy and healthy. We encourage you to try treating your diabetic pet. If you have concerns, please talk with your veterinarian, the technicians who work at the hospital, and check out web sites that will provide you with a wealth of information.

What are the signs of valvular insufficiency?

Owners of pets with valve problems see inappropriate panting, heavy breathing, diminished exercise ability, fatigue, cough, and occasionally fainting. The cough usually starts at night and progresses to daytime as well, particularly when associated with exercise. Retching and nonproductive gagging follow the cough. When the right side of heart is affected, fluid may accumulate around the lungs, making it difficult to breathe, and in the abdomen, making it swell.

What tests are needed?

Abnormal heart sounds heard with a stethoscope suggest the need for an electrocardiogram (ECG) to identify heart enlargement or irregularities of the heart’s rhythm. Radiographs (x-rays) can demonstrate heart enlargement and/or inappropriate fluid accumulation. Blood testing can identify hormonal, kidney, or other internal medical problem. An ultrasound examination (echocardiography) accurately pictures enlarged heart chambers, abnormalities of valve structure, and the heart’s pumping ability. These tests assess heart function and severity of the disease and identify the need for therapy.

What is the treatment?

A number of treatments are used for pets with valvular heart disease, including exercise restriction. Walking is good exercise. Digitalis is a medication used to strengthen the heart and to treat some irregularities of its rhythm. It maintains a slower and more effective heart muscle contraction. Signs of digitalis excess include loss of appetite, lethargy, vomiting, and diarrhea. ECG monitoring permits the veterinarian to supervise the pet’s progress. Diuretic agents are commonly given to remove excess water accumulation from the body and can cause increased water drinking and urination. Diuretics can induce weakness, dehydration, and blood salt abnormalities. Alterations in electrolyte (salt) levels are identified through periodic testing of the pet’s blood. Angiotensin-converting enzyme inhibitors (ACEIs) are drugs that improve the body’s ability to reduce salt and water retention, to reduce high blood pressure, and to limit the effect of hormones that adversely affect heart muscle. Given in excess, ACEI drugs cause malaise, blood salt disturbances, loss of appetite, and possibly kidney damage. Antiarrhythmic agents may be given to stabilize the cardiac rate and rhythm. Drugs to decrease blood pressure and nutritional supplements may be required for specific conditions.

To control the symptoms of heart failure, low-salt (sodium) diets may be suggested. The kidney normally removes excess sodium, but this does not occur as effectively in heart failure. Commercial low-salt diets, varying from moderate to extreme restriction, are effective in preventing salt and water retention. These diets are recommended only after heart failure has been diagnosed. A modest reduction in salt intake may be indicated before the onset of heart failure. If the pet refuses to eat a commercial diet, low-salt foods can be prepared by the owner under veterinary direction. Mixing low-salt diets with regular (high-salt) diets or feeding snacks high in sodium is not recommended.

Longevity and quality of life in dogs with this disease vary with the severity of the valve damage and the amount of blood leakage into the upper chambers of the heart. Concurrent medical conditions, age, and the physical status of the pet play a large role in determining the animal’s prognosis. Clinical signs are progressive, and although they may be decreased, they never entirely resolve. Medical therapy can enhance the quality of life of the pet as well as increase life expectancy. Dogs with left-sided valvular heart disease treated with medication and a low-salt diet have an average life expectancy of about 9 months from the time heart failure begins. Abdominal fluid accumulation and body emaciation are signs of right-sided heart failure. Regularly removing the extra fluid may increase life expectancy. Surgical replacement of the valves is not an option in dogs at this time.

In three large canine splenic disease studies encompassing approximately 2000 dogs, a “rule of two thirds” was found suggesting that approximately two thirds of dogs with a splenic mass have a cancer (therefore one third are not malignant) and two thirds of the malignant tumors of the spleen are HSA. HSA is a disease generally of older dogs and cats with an average onset of 9 to 10 years; however, there are reports of extremely young dogs and cats with this disease (5 to 6 months to a few years of age). German shepherd dogs are most commonly diagnosed with HSA; however, other large breed dogs such as golden retrievers and Labrador retrievers may also be overrepresented. In cats, the most common breed is the domestic shorthair.

The cause of HSA in dogs and cats is presently unknown. Exposures to toxins such as chemicals, insecticides, and radiation have been reported in humans to be associated with HSA. Ultraviolet light exposure from the sun may be a potential cause of HSA in dogs, as HSAs of the skin are commonly seen in dogs with light hair and poor pigmentation (e.g., Salukis, Whippets, and white Bulldogs).

What are the signs of hemangiosarcoma?

HSA can be found in dogs or cats in almost any location and therefore the history and clinical signs can be extremely variable and dependent on where the tumor is located. At the most extreme, HSA can cause sudden death due to tumor rupture and/or dramatic blood loss. At the other end of the spectrum, nonspecific signs may include the following:

• Decreased appetite
• Vomiting
• Lethargy

Commonly pets may have episodes of one or more of the following:

• Weakness
• White/pale mucous membranes
• Collapse
• Distended abdomen
• Difficulty breathing
• Weight loss

Episodes of weakness and collapse can last for minutes to hours with recovery from the episode being a common feature. Most likely the weakness, white/pale mucous membranes, and collapse are due to rupture of the tumor and blood loss, whereas the recovery is likely due to a combination of the blood loss stopping and lost blood being resorbed back into the circulation. However, an additional problem associated with this blood loss is the dissemination (spread) of cancer cells into areas that contact the lost blood (inside the abdomen or chest, or via the bloodstream). This propensity to spread is what makes treatment of this cancer so particularly difficult.

When HSA is present in the heart, blood loss can result in fluid surrounding the heart or lungs. This can cause difficulty breathing and problems with the heart being able to pump effectively. When HSA is present in the brain, it can cause a variety of neurologic signs including convulsions. The skin form of HSA can cause skin masses that are firm, raised, and dark purple to red in color.

What tests are needed?

When HSA is diagnosed or highly suspected, your veterinarian will recommend performing a number of “staging tests” to determine the degree of spread. This will help him to guide you toward making informed decisions regarding treatment. These tests may include the following:

• Blood work
• Urinalysis
• Coagulation/bleeding panel
• X-rays
• Ultrasound
• Needle aspiration

What treatment is needed?

Surgery continues to be the best treatment for dogs and cats with HSA. Treatment for this cancer has two main considerations: 1) local tumor control, or what surgery can address, and 2) systemic tumor control, or metastasis; what surgery cannot address. Therefore although surgery remains the best treatment for HSA, it is almost always used in concert with some systemic therapy such as chemotherapy.

Unfortunately, the average survival time for dogs with HSA (all but the skin-only cases) treated with surgery alone (no systemic therapy) is only 1 to 3 months, with most dogs dying of metastasis (spreading of cancer cells). Cats share this poor prognosis with dogs; the average survival time for cats undergoing removal of the spleen for HSA was only 20 weeks. Surgery should be utilized as aggressively as possible for HSA to remove all diseased tissue whenever possible.

In contrast, dogs who are treated with surgery AND systemic therapy such as chemotherapy average an 8- to 9-month survival time post-surgery, assuming no overt evidence of metastasis at the time of surgery. Chemotherapy slows the growth of tumors, and to help the patient enjoy a high quality of life in spite of the progression of the disease. Dogs and cats tend to handle chemotherapy remarkably well. The psychologic stress of a cancer diagnosis is not an issue for dogs and cats, and the dosage of chemotherapy medications can be lowered if physical side effects are noted, as the goal of chemotherapy in veterinary medicine is to increase quality, not quantity of life.

At present, the chemotherapy drug of choice is a drug called doxorubicin (Adriamycin). Unfortunately, the use of this drug does not lead to a cure and it is used to try to slow the tumor and provide a good quality of life. Instead of the aforementioned 1 to 3 months survival with surgery alone, recent studies suggest an average of 8 to 9 months with surgery and chemotherapy as long as there is no overt evidence of spread at the time of surgery.

HSA of the superficial skin of dogs appears to be a less aggressive variant of HSA. The average survival time of dogs with superficial skin HSA treated with surgery was approximately 2 years. Cats with HSA of the skin treated with surgery had an average survival time of approximately 1 year.

What treatment is the prognosis?

Doctors that have studied HSA have found the following factors to be associated with pets doing more poorly than the average:

• Younger age
• More aggressive looking tumor under the microscope (“grade”)
• Incomplete tumor removal
• Visible evidence of metastasis (spread)
• History of tumor rupture leading to dissemination of cancer cells inside the abdomen, chest, or any other site the tumor ruptured into

It therefore appears that the use of chemotherapy after surgery is most beneficial in dogs with HSA caught early that has not ruptured and is completely surgically removed. Veterinary oncologists and veterinary oncology researchers are continually investigating new types of treatments for this and other extremely aggressive tumors in the hopes of providing the maximal amount of good quality life.

Mammary tumors are similar to breast tumors in people. Usually no symptoms occur other than finding a “lump” when petting your dog or cat. Uncommonly, mammary tumors can bleed or become infected. Because some of these tumors are malignant, the can spread to other parts of the body and cause illness (loss of appetite, weight loss, lethargy, etc.).

What are the symptoms of mammary gland tumors?

Mammary tumors are similar to breast tumors in people. Usually no symptoms occur other than finding a “lump” when petting your dog or cat. Uncommonly, mammary tumors can bleed or become infected. Because some of these tumors are malignant, the can spread to other parts of the body and cause illness, loss of appetite, weight loss, or lethargy.

What tests are needed?

The diagnosis of a mammary gland tumor relies primarily on evaluation of a biopsy. A safe rule of thumb regarding mammary gland tumors is that about 50% of these tumors are benign and 50% are malignant. Further, 50% of the malignant tumors in dogs can be cured with just surgery. Unfortunately, mammary gland tumors in cats are almost always malignant. In dogs and cats, the smaller the tumor is at the time of diagnosis the better the outcome.

Tests that may help your veterinarian define your pet’s prognosis by checking for metastasis (spread of cancer) include the following:

• X-rays of the thorax and abdomen
• Abdominal ultrasound
• Biopsy of lymph nodes that drain the site of the tumor
• Fine needle aspirate of lymph nodes that drain the site of the tumor
• Blood work to evaluate overall health of pet

What treatment is needed?

All dogs with benign mammary tumors can be cured with surgery. As mentioned above, 50% of dogs with malignant mammary gland tumors can be cured with surgical removal of the mass. However, even if the tumor is completely removed with surgery, your dog may develop another mammary tumor in the future. For the 50% of dogs with malignant tumors that cannot be cured with surgery, chemotherapy may also be offered (see discussion below).

Factors that help your veterinarian decide whether your dog should be treated with chemotherapy rather than surgery alone include the following:

• The size of the tumor at the time of diagnosis
• Whether or not the tumor site is ulcerated
• If evidence exists of spread of the tumor to the lymph nodes, lungs, or other sites of the body
• Characteristics of the tumor on microscopic examination

Some drugs that are commonly used to treat dogs with malignant mammary gland tumors are piroxicam, doxurubicin, and cyclophosphamide. Piroxicam is an anti-inflammatory drug that also has anticancer activities. The main side effects of piroxicam include loss of appetite and vomiting secondary to stomach irritation. The side effects may be minimized by giving the medication with food. If your pet has a diminished appetite, vomiting, or a change in the consistency of stool while on piroxicam, discontinue the medication and contact your veterinarian. The other drugs listed are more traditional anticancer drugs (i.e., chemotherapy drugs).

Two equally important goals should be kept in mind when choosing chemotherapy to treat your pet:

1. Control the tumor for as long as possible
2. Maintain a good to excellent quality of life throughout the duration of treatment

The chemotherapy drugs used for dogs and cats are the same drugs used in people. Because maintaining a normal quality of life is a main goal, chemotherapy is used somewhat less aggressively than in human medicine. Also, dogs and cats seem to be more tolerant of chemotherapy than people. They do not usually have side effects as severe as those in people. However, because chemotherapy drugs affect rapidly dividing cells, side effects can occur in dogs and cats.

Two important sets of cells in the body naturally grow and divide rapidly. These are the following:

1. The cells that line the bone marrow
2. The cells that line the gastrointestinal tract

A complete blood count (CBC) should be performed immediately before and 7 to 10 days after your pet has chemotherapy. If the white blood cell count is low, chemotherapy will be delayed 4 to 7 days; the counts will come back up on their own. Rarely the white blood cell count may drop so low that your pet is at risk of developing an infection. In this situation, antibiotic therapy is indicated. At home, you may notice that your pet has a decreased appetite for 2 to 3 days after chemotherapy. You may also notice that they have softer stool than 4 to 7 days after chemotherapy. If you feel that vomiting or diarrhea is severe, contact your veterinarian. Medication may be used to help minimize or control these side effects.

What are the symptoms of transitional cell carcinoma?

A diagnosis of TCC is suspected when the following symptoms are exhibited:

• Straining to urinate
• Urinating small amounts frequently
• Blood in the urine

These symptoms are not specific for a bladder tumor. Animals with bladder infections or bladder stones may behave the same way. A bladder may be suspected in animals with these symptoms if they have only temporary relief or no relief from antibiotic therapy.

What tests are needed?

It is rare that a bladder tumor can be felt by palpating (feeling) the belly, and most bladder tumors do not show up on x-rays. Some tests your veterinarian may recommend if a bladder tumor is suspected include the following:

• Urinalysis, or microscopic examination of a urine sample
• X-rays and ultrasound of the abdomen
• Biopsy to confirm the diagnosis
• X-rays of the lungs to check for potential spread of the tumor
• Urine culture and blood work to assess the overall health of the pet to help determine what treatment options could be offered

What treatment is needed?

Several possible treatments exist for TCC:

• Surgery may be a treatment for cats with TCC, because the tumor tends to involve a part of the bladder that is not essential for bladder control. Surgery is not usually a good treatment option for TCC in dogs because the tumor is often located in the neck of the urinary bladder. Surgery in this site may render the dog incontinent (unable to control urination) plus the surgery is rarely curative. However, if your pet cannot pass urine because they are obstructed by the tumor, a surgical procedure called a tube cystostomy may be an option. The advantages of a tube cystostomy are that they are easy to manage, they allow animals to pass urine, and they are relatively easy to place. The disadvantages are recurrent urinary tract infections and occasional complications (e.g., the tube is pulled out, or the pet chews through the tube). Animals with tube cystostomies need to have their urine cultured on a regular basis. They also may require continual antibiotic therapy.
• Drug therapy is the most common treatment for TCC. Up to 40% of dogs with TCC may have a response to medical therapy, with response defined as at least50% decrease in tumor size. Although not all tumors shrink in response to therapy, another positive response is a decrease in the growth rate of the tumor. Medications that may have some effect against TCC in dogs or cat include the following:

1. Piroxicam
2. Mitoxantrone
3. Carboplatin
4. Doxurubicin
5. Cyclophosphamide

Piroxicam is an anti-inflammatory drug that also has anticancer activities. Its main side effects include loss of appetite and vomiting secondary to stomach irritation. These side effects may be minimized by giving the medication with food. If your pet has a diminished appetite, vomiting, or a change in the consistency of their stool while on piroxicam, discontinue the medication and contact your veterinarian. The other drugs listed are more traditional anticancer drugs (i.e., chemotherapy drugs).

Two equally important goals must be kept in mind when choosing chemotherapy to treat your pet:

1. Control the tumor for as long as possible.
2. Maintain a good to excellent quality of life throughout the duration of treatment

The chemotherapy drugs used for dogs and cats are the same drugs used in people. Because maintaining a normal quality of life is a main goal, chemotherapy is used somewhat less aggressively than in human medicine. Also, dogs and cats seem to be more tolerant of chemotherapy than people, and they do not suffer side effects as severe as those in people. However, because chemotherapy drugs affect rapidly dividing cells, side effects can occur in dogs and cats.

Two important sets of cells in the body naturally grow and divide rapidly. These are cells that line the bone marrow (which is where the red and white blood cells come from), and the cells that line the gastrointestinal tract. A complete blood count (CBC) should be performed immediately before and 7 to 10 days after your pet has chemotherapy. If the white blood cell count is low, chemotherapy will be delayed by 4 to 7 days; the counts will come back up on their own. Rarely the white blood cell count may drop so low that your pet is at risk of developing an infection. In this situation, antibiotic therapy is indicated. At home, you may notice that your pet has a decreased appetite for 2 to 3 days after chemotherapy. If you feel that the vomiting or diarrhea is severe, contact your veterinarian. Medication may be used to help minimize or control these side effects.

Occasionally, radiation therapy may be used to help relieve some of the clinical signs associated with the tumor. Used in this manner, there should not be any side effects of the radiation. Your veterinarian will help determine the best treatment option for your pet.

What is the prognosis?

Ultimately, TCC is considered to be a fatal disease. With treatment, average survival times following diagnosis are around 10 to 12 months. However, the quality of life for most pets being treated for TCC is excellent, and your pet should be happy and comfortable during his/her treatments.

Although MCTs most commonly afflict middle-aged to older dogs, they are also found with surprising frequency in pets that are young. Approximately 10% to 15% of dogs with this cancer develop multiple MCTs throughout their lifetime. When this unique behavior occurs, the tumors may seem to erupt simultaneously or develop over months to years.

What are the signs of mast cell tumors?

A wide range of signs are associated with MCT. Most common are variably sized skin swellings. Other signs that are commonly associated with MCT are related to the unique role that normal mast cells play in animals and humans. If you look at a normal mast cell under the microscope, you will often see a number of purple “granules” within the cell. Histamine and other substances that play important roles in inflammation are within these granules and are responsible for many of the signs that you might see in people with allergic reactions after a bee sting or asthma attack. Therefore if the contents of these granules are released from a MCT, their symptoms may include the following:

• Swelling, itching, redness, skin ulceration, or bruising at the tumor site
• Changes in size and shape of mass, particularly after it has been manipulated
• Abdominal discomfort and vomiting may indicate ulceration of the gastrointestinal (GI) tract, caused by histamine release from the granules
• Anemia, caused by extensive bleeding into the stomach or intestines

What tests are needed?

When making decisions regarding a dog with MCT, three questions should be addressed:

1.     Is there evidence that the tumor has spread in my dog?

Mast cell tumors tend to spread first to lymph nodes that are near the tumor. For that reason, the most valuable diagnostic tests that may be recommended are the following:

• Aspiration cytology (withdrawal of a small tumor sample via placement of a small needle into the tumor) of such “regional” lymph node
• Biopsy (surgical removal of a sample of the tumor) of such “regional” lymph node.

After lymph nodes, MCT may spread to the spleen, liver, and bone marrow. Whether testing of these additional sites is indicated will be based upon the ease of obtaining a good sample from the lymph node, the apparent aggressiveness of the pet’s MCT, and the clinical judgment of your veterinarian. In most circumstances, testing of blood, liver, spleen, and bone marrow will be associated with a lower yield of helpful information. This is explained by two facts: first, small numbers of normal mast cell tumors may be found in these particular organs. Therefore it may be difficult to differentiate an increased number of normal mast cells in these organs from similar looking cells that represent tumor spread. Recall that normal mast cells are part of the response to allergic diseases. Secondly, the incidence of tumor spread to internal organs (spleen, liver, bone marrow) is quite uncommon with low-grade or well-differentiated mast cell tumors. Unfortunately, if evidence of MCT spread is documented in lymph nodes or internal organs, the chance for cure is reduced. Instead of common treatments, your veterinarian may discuss different types of therapy with you.

2.     What is the grade of my dog’s MCT?

After a biopsy or tumor removal, the pathologist will evaluate the tumor tissue and report if it fits the criteria that best describes an MCT that is

• Grade I: A more well-differentiated or lower grade tumor
• Grade II: A tumor with intermediate differentiation that extends more deeply into surrounding tissues
• Grade III: A higher grade, poorly differentiated tumor that may replace the skin and underlying tissues

This report will be important in providing information that is useful for predicting how aggressively this tumor may spread and whether additional therapy such as chemotherapy should be added to the treatment plan. As the tumor grade increases, the chance for spread to internal organs is also higher. The pathologist will also determine whether the entire tumor was removed or if tumor cells remain behind. If tumor cells remain behind, you may be provided with additional options for treatment including a second surgery, radiation therapy, or chemotherapy.

3.     Are there other MCTs or clinical factors that may affect decision-making?

It is certainly possible to remove more than one mast cell tumor from a dog. However, some dogs develop dozens of tumors almost simultaneously or develop new tumors with such rapid frequency that local treatment options such as surgery or radiation become less effective. Other medical conditions may impact decisions in such dogs, particularly if your pet is so sick that anesthesia itself becomes life threatening.

What treatment is needed?

The treatment options that may be prescribed for a MCT include the following:

• Surgery
• Radiation therapy
• Chemotherapy
• Supportive medical care

Appropriate treatment choices for each individual pet will be made based upon your preferences and answers to the three questions discussed above. The unpredictable behavior of MCTs must always be kept in mind when making therapeutic decisions. For Grade I or II MCTs, complete surgical resection is typically the treatment of choice. With these more well differentiated tumors, the chance of spread to other organs is lower and the primary focus is to effectively treat the tumor locally.

Because MCTs are often more extensive than they would initially appear, your veterinarian may remove more tissue and leave a longer incision than you would have anticipated. This is often necessary if the surgery is done with curative intent. Sometimes, the tumor is located in an area that would be difficult to completely remove. In this case, a large portion of the tumor may be removed with the option of following with another type of therapy, such as radiation, after the surgical incision has healed. The most common reason to recommend radiation therapy would be in cases where all of the MCT could not be removed, tumor cells were left behind, and further surgery is not deemed possible.

For dogs with high-grade, poorly differentiated tumors, surgery and radiation may be used as local therapies, but these treatments will not address the high risk of cancer spread. For Grade III tumors, which have a high likelihood of spreading to other organs, and in cases with documented metastasis, regardless of the grade, chemotherapy may be offered as a palliative treatment alternative. Response to chemotherapy is somewhat unpredictable, but in most reports, it is suggested that approximately 30% to 40% of cases will have some response to the drugs that are currently most commonly used. Supportive medical care is appropriate for all patients and can include antihistamines, gastrointestinal protectants, and in some circumstances, corticosteroids.

What is the prognosis?

The clinical course of MCTs is somewhat unpredictable, but all tumors are considered potentially malignant because of their ability to metastasize, or spread. Generally the spread potential for well-differentiated tumors is low (<10%) and that of intermediate grade tumors is low to moderate. Poorly differentiated tumors are associated with the greatest risk of metastasis and the shortest survival times.