Environmental Allergy Testing  

By: Dr. Loren Candito, Dermatology

Summer is right around the corner. Along with warmer weather and days at the beach comes another challenging allergy season for our itchy patients.  
Environmental allergies are such a frustrating condition for our patients and clients. There is absolutely a role for the newer symptomatic immunomodulatory therapies (Cytopoint, Apoquel, and Atopica), and there are still conditions where steroids are still indicated, but we may best serve patients and clients by using these treatments to improve immediate comfort, while performing our allergy work up to aid in long-term comfort.  For chronic allergy patients, allergen specific immunotherapy is a safe and often very effective therapy that should be considered as a first line treatment option. 
Allergen specific immunotherapy is the only allergen treatment that has the potential to reverse the atopic condition, and offers a safe and effective therapy that minimizes the need for long-term immune suppressing medications for many patients.  
Which patients are good candidates? Any dog or cat that is greater than 1 year of age, with seasonal signs or year round signs that have no response to a strict elimination diet trial, is a candidate for allergy testing.  
Special considerations for testing For environmental allergy testing, both intradermal testing and serum allergy testing is ideally recommended for every patient, as some pets test better on one test than the other and often the results do not entirely overlap between the tests (serum testing does have an increased risk of false negatives and false positives over intradermal testing).   Standard Northeastern regional allergens are used, and special allergens of interest to clients can also be included with intradermal testing (rabbit dander, cat dander, and so on). 


Intradermal testing procedure and outcome For skin patch testing, a light sedation is used, and the test site usually no bigger than 8x8cm, minimizing cosmetic disruption of the coat. Northeast regional allergens are tested via injections into the skin with tiny needles, with results of inflamed, red skin if allergy is present within 20 minutes.  Based on the results, a customized serum called allergen immunotherapy will be created to be administered via weekly to bi-weekly allergy injection or daily oral drop. 

Feline Lymphoma

Lymphosarcoma, commonly called lymphoma, is one of the most common cancers diagnosed in cats. It is a cancer of the lymphocytes (a type of white blood cell) and lymphoid tissues. Lymphoid tissue is normally present in many places in the body including lymph nodes, spleen, liver, gastrointestinal tract and bone marrow.

Unlike lymphoma in dogs, viral causes of feline lymphoma are well defined. Infection with the feline leukemia virus (FeLV) has been shown to cause a significant (~60 fold) increase in risk for development of lymphoma in cats. Cats with the feline immunodeficiency virus (FIV) are also at increased risk of developing lymphoma (7 fold) and infection with both viruses confers a 77 fold increase in risk. Cats of any age, breed and of either sex can be affected. We typically see lymphoma in younger cats that are infected with the feline leukemia virus, and in older cats that are not infected with the virus. Other possible risk factors include exposure to second hand tobacco smoke, chronic immunosuppressive therapy, as well as chronic inflammatory diseases.

Types of Lymphoma
Lymphoma can be subdivided into several different forms, depending on the primary or predominant site of the tumor. Some cats have multiple sites of involvement and do not fit well into just one category. These are usually animals with very advanced disease.

1. Gastrointestinal Tract: The most common form is involvement of the gastrointestinal (GI) tract. This includes the stomach, intestines and liver; as well as some of the lymph nodes surrounding the intestines. Cats with this type of lymphoma often have clinical signs consisting of vomiting, diarrhea, weight loss or a decreased appetite.

2. Mediastinal: The mediastinum is a term used for a special aggregation of lymphoid tissue in the chest. Cats with this type of lymphoma often are seen because of difficulty breathing due to a large mass in the chest or an accumulation of fluid around the lungs.

3. Renal: The kidneys may be the primary sites of involvement. Cats that have this type are often seen because of signs related to kidney failure (increased thirst, increased urination, loss of appetite, vomiting).

4. Bone Marrow: If the cancer were confined to the bone marrow, it is considered leukemia. The signs that we see in cats are usually related to the decreased numbers of normal cells such as red blood cells that carry oxygen, white blood cells that fight infection and platelets that help with clotting - all of which are made in the bone marrow. Anemia (low red blood cell counts), infections and bleeding are common problems.

5. External Lymph Nodes: In a few cats, the only site of involvement is the external lymph nodes. These cats may be seen because of problems such as vomiting and loss of appetite or because the owner found “lumps” (enlarged lymph nodes) on their cat.

6. Other Sites: We will occasionally see other sites such as the skin, nose, brain and spinal cord as the primary site of involvement

Diagnosis and Initial Evaluation
A biopsy (tissue) or cytology sample is required in order to make a diagnosis of lymphoma. In some cases, we can obtain a diagnosis by a fine needle aspirate but sometimes a biopsy to obtain a larger piece of tissue is necessary to confirm the diagnosis. The ease with which a diagnosis can be obtained depends upon where the tumor is located.

A complete evaluation of a cat suspected of having lymphoma includes determining the extent of the cancer (i.e. looking for spread of the cancer to other sites) which is known as staging. A complete blood count (CBC), serum chemistry profile (which looks at things such as liver and kidney function, protein levels, blood sugar and electrolytes), urinalysis and FeLV/FIV testing are always recommended and provide important information regarding the effects of the cancer on body functions as well as the ability of the patient to handle chemotherapy or other treatments. Additional tests may include radiographs, abdominal ultrasound, bone marrow aspirate and CT/MRI. Chest radiographs (x-rays) allow us to look for internal lymph nodes, lung involvement, an enlarged mediastinum or fluid around the lungs. An abdominal ultrasound allows us to evaluate the liver, spleen, internal lymph nodes and intestinal tract for possible tumor involvement. A bone marrow aspirate allows us to look for tumor cells in the bone marrow as well as to evaluate the marrow’s ability to produce normal blood cells. Once we know the extent of disease, we can then decide on the best treatment for each individual patient.

Treatment and Prognosis
Chemotherapy is the mainstay of treatment for lymphoma; however, there may be situations when surgery and/or radiation are also indicated. Radiation therapy may be recommended if the cancer is localized to one site such as the nasal cavity. Often surgery or radiation therapy is used in addition to chemotherapy. Specific recommendations will be discussed based on your pet’s particular situation.

Lymphoma is very responsive to chemotherapy and 50-60% of treated cats will go into remission. The definition of remission is the complete disappearance of detectable cancer; however, microscopic amounts of tumor cells can remain hidden in the body. A remission is NOT a cure but it does allow your pet to experience a good quality of life without clinical signs associated with their disease. The length of the remission depends upon many factors including the primary site, how sick an animal is at the start of treatment and the extent of disease. In most situations, the average remission and survival times (with chemotherapy) are between six to twelve months; with about 30% of cats experiencing disease control for greater than one year and approximately 10-15% of cats living longer than two years.

Solitary lymphoma such as nasal is generally treated with radiation +/-chemotherapy. The radiation can be considered definitive with the intent for long term control or palliative for symptom relief in order to improve/maintain the patient’s quality with minimal negative impact. The prognosis for solitary lymphoma such as nasal lymphoma is generally better with many cats achieving local control for 1-1.5 years although there is still a concern that the cancer may spread within 3-6 months. If solitary lymphoma is treated with radiation and the cancer spreads later in life chemotherapy can be considered at that time.

The exact chemotherapeutic drugs and schedule will depend upon how aggressively the cancer is behaving, how sick an animal is at the start of treatment and any abnormalities in organ function, particularly kidneys and liver as well as the goals of treatment. Chemotherapy is more effective when we use a combination of drugs; therefore, most protocols generally consist of 4-6 different drugs. This is called a multi-drug protocol. Initially, treatments are given more frequently (i.e. once weekly) and then, depending upon the response and protocol used, are gradually spread out and/or discontinued. Other options for therapy may consist of using a single chemotherapy drug (single agent therapy) at 3- week intervals, or palliative care which is simply designed to keep your pet comfortable at home for as long as possible. While palliative care with drugs may provide comfort it generally only yields 1-2 month survival times. A disadvantage to single agent therapy is that remission rates and expected survival times are much more difficult to predict with these protocols. Bloodwork and/or radiographs and ultrasounds are generally repeated at regular specified intervals to monitor for side effects (such as a low white blood cell count) and to determine the pet’s response to treatment.

If a patient comes out of remission or relapses, we can try to put them back into remission using either new combinations of the same drugs or different drugs. Unfortunately, the chances of obtaining a second remission are lower; however, there are some cats that do respond and have additional time with a good quality of life.

Side effects
Most cats tolerate chemotherapy very well and experience minimal side effects. Serious side effects are only seen in 5-10% of the patients we treat. If side effects are serious or intolerable, we can consider either lowering the dose of the offending drug or substituting a different drug. Side effects include nausea, vomiting and loss of appetite, diarrhea, extreme tiredness or rarely infection. Certain chemotherapy agents can affect organ function over time. Cats do not lose their hair but may lose their whiskers and have a different texture to their fur secondary to chemotherapy.

Hyperthyroid Cats and the IDEXX SDMA Test for Kidney Function

Hyperthyroidism is a disease seen primarily in older cats, in which kidney disease is also common. The clinical challenge is that hyperthyroidism can mask the presence of kidney disease, and until now, there has not been a reliable routine diagnostic test that can assess kidney function in cats affected by hyperthyroidism.

Creatinine is a common test for kidney disease and is measured with a blood test. Creatinine, being a by-product of muscle, is under-produced in feline hyperthyroidism as a result of muscle loss, and thus becomes a poor indicator of kidney function in hyperthyroid cats. Creatinine is also lowered by the hyperfiltration associated with the increased metabolic state that is common in hyperthyroid cats.

IDEXX Laboratories has developed a test, the SDMA Test, which is NOT impacted by weight loss and muscle mass and appears to be only slightly blunted by hyperfiltration, making it a much more reliable marker of kidney function in hyperthyroid cats.

Infiltrative Bowel Disease in Cats

What does Infiltrative Bowel Disease mean?
The small intestinal tract is a remarkable organ. It has to neutralize acid from the stomach, apply digestive enzymes and emollients, absorb and conduct away the microscopic nutrients, and move its contents from one end of our body to the other. There is also the matter of housing a variety of bacteria without allowing them to access the interior of our body, immunological reactivity, hormonal activity and response, and more. Its layers act as both a barrier and gateway, plus it must have muscle strength for tone and motion. Proper function depends in part on normal thickness of all the delicate layers.

Diseases of Infiltration:
Disease can lead to an influx of inappropriate cells into the layers of the intestine. This infiltration of the bowel by abnormal cells creates thickening and puffiness, which hampers function. The thick intestine does not contract properly, which leads to food pooling and sludging. Pooling and sludging leads to the sensation of nausea and malaise. The thick intestine also cannot absorb nutrients properly, which leads to weight loss and diarrhea. Frequently there is ulceration and bleeding as the membranes become unhealthy.

Bacterial populations become altered when the nutrients available to them change in composition. In other words, what sort of bacteria live in the bowel depends on what nutrients are in abundance around them. Different nutrients promote different bacterial populations for better or worse. Abnormal nutrient absorption can lead to an overgrowth of bacteria or at least an alteration in the proportions of different populations of bacteria, creating a bad neighborhood in the bowel. Toxic bacterial products can be produced. Bacteria can overpower natural barriers, allowing them to crawl up the pancreatic duct or bile duct where they create inflammation in organs that are normally sterile (pancreas and liver).

Fixing it Depends on Knowing the Nature of the Infiltration
There are two common diseases that involve infiltration, intestinal lymphoma and inflammatory bowel disease (IBD). Both diseases involve lymphocytes infiltrating the delicate bowel. In lymphoma, these are malignant cancerous lymphocytes. In IBD, they are active lymphocytes reacting inappropriately to an immunological trigger (such as a food or bacterial waste product). Biopsy is necessary to distinguish these two diseases and distinguishing between the two conditions, allowing for the most effective treatment.

Treating Lymphoma
There are two forms of lymphoma, one associated with a rapid and sustained response to therapy with remissions of one year or longer being common, and the other type being nearly untreatable. Biopsy will determine which type a cat has. Confirmation of lymphoma also allows for a more tailored protocol so as to maximize the quality of remission.

Treating Inflammatory Bowel Disease
IBD is an immune-mediated disease and treatment centers on suppressing the inappropriate immunological response so that the bowel can recover. Special diets may be employed to minimize inappropriate reactions to food in long-term management. It is theoretically possible, eventually, to recover from this disease completely, though most patients need long-term medications to control the inflammation.

The possibly good news here is that because both conditions involve lymphocyte infiltration, there is a great deal of overlap in therapy, so it is possible to make up a treatment plan that will cover both possibilities with a reasonable chance of success. This is not optimal but provides a route to less expensive therapy.

Diagnostics Start with Ultrasound
The normal diagnostic sequence involves basic examination, lab work to rule out metabolic issues, and abdominal ultrasound followed by either endoscopy to obtain intestinal biopsies or exploratory surgery to obtain biopsies. A great deal of information can be obtained by ultrasound. Ultrasound allows for evaluation of tissue not accessible during endoscopy or even surgery. Further, it may even be possible to get the diagnosis without the expense and stress of intestinal biopsy if tissue can be obtained by ultrasound guidance.

That said, there are some caveats to the use of ultrasound as the final diagnostic. For example, there is a great deal of over-lap in bowel thickness between what normal patients have, what IBD patients have, and what lymphoma patients have. Normal patients will not have abnormal layering but sick patients can have completely normal layering. More severe disruptions in layering are more typical of lymphoma, especially when they occur in separate segments, but less severe wall thickness change is not very specific.

Some diagnostic considerations with abdominal ultrasound are as follows:

  • Severe bowel layer distortion implies (but does not confirm) malignancy
  • Milder bowel layer changes could be from either IBD or lymphoma
  • If any lymph nodes are enlarges, they may be aspirated with guidance from the ultrasound. If lymphoma is found, the diagnosis is made. If the node is immunologically reactive only, this does not rule out lymphoma but implies benign disease
  • If no lymph nodes are enlarged, the liver may be aspirated. If lymphoma is found, the diagnosis is made. If lymphoma is not found in the liver, it is not ruled out in the intestines
  • Growths or masses may be discovered that are best managed with surgical removal
  • Disease in other organs may be discovered

If ultrasound findings are not specific and the diagnosis remains ambiguous, in a perfect world referral for endoscopy follows, biopsy samples are taken, and a tailored therapy can initiate, or at least informed decisions can be made. Not every patient is stable for anesthesia, however, and not every owner is financially able to pursue a specialized procedure.

Because there is a great deal of overlap between the treatment for IBD and the treatment for lymphoma, a therapy plan can be designed that covers both possibilities reasonably well. Typically this involves corticosteroids, immunosuppressive medications, special diet, probiotics and nutritional supplements. Response to medication is generally rapid (within a week or two) for IBD, and a common lymphoma statistic is that 75% will achieve remission within three weeks regardless or protocol. Longer remissions can be obtained with more tailored protocols.

Heart Murmurs in Cats

Extra heart vibrations that are produced as a result of a disturbance in the blood flow—enough, in fact, to produce audible noise—are referred to as murmurs. Often, the murmurs are classified according to a variety of characteristics, including their timing. Systolic murmurs, for example, occur when the heart muscle contracts; diastolic murmurs occur when the heart muscle relaxes between beats; and continuous and to-and-fro murmurs occur throughout all or most of the cardiac cycle.

Symptoms and Types
The symptoms associated with murmurs depend on a variety of characteristics, including their grade, configuration, and location. If, however, the murmur is associated with structural heart disease, your cat may display signs of congestive heart failure such as coughing, weakness, or exercise intolerance.

Grading Scale for Murmurs

  •  Grade I – barely audible
  •  Grade II – soft, but easily heard with a stethoscope
  •  Grade III – intermediate loudness; most murmurs which are related to the mechanics of blood circulation are at least grade III
  • Grade IV – loud murmur that radiates widely, often including opposite side of chest
  •  Grade V – very loud, audible with stethoscope barely touching the chest; the vibration is also strong enough to be felt through the animal’s chest wall
  • Grade VI – very loud, audible with stethoscope barely touching the chest; the vibration is also strong enough to be felt through the animal’s chest wall


  • Plateau murmurs have uniform loudness and are typical of blood regurgitation through an abnormal valvular orifice (regurgitant murmurs).
  • Crescendo-decrescendo murmurs get louder and then softer and are typical of ejection murmurs due to turbulent forward flow.
  • Decrescendo murmurs start loud and then get softer and are typical of diastolic murmurs.

Murmurs are caused by the following:

  • Disturbed blood flow associated with high flow through normal or abnormal valves or with structures vibrating in the blood flow.
  • Flow disturbances associated with outflow obstruction or forward flow through diseased valves or into a dilated great vessel.
  • Flow disturbances associated with regurgitant flow due to an incompetent valve, patent ductus arteriosus, or a defect in the septum (the wall that separates the heart’s right and left sides).

More specifically, the following are some conditions and diseases that may bring on murmurs:

  • Systolic Murmurs
  • Anemia
  • Hyperthyroidism
  • Heartworm disease
  • Mitral and tricuspid valve heart failure
  • Cardiomyopathy and aortic valve insufficiency
  • Mitral and tricuspid valve dysplasia
  • Systolic anterior mitral motion (SAM)
  • Dynamic right ventricular outflow obstruction
  • Dynamic subaortic stenosis
  • Aortic stenosis
  • Pulmonic stenosis
  • Atrial and ventricular septal defect
  • Tetralogy of Fallot
  • Mitral and tricuspid valve endocarditis (inflammation of the inner part of the heart)

Continuous or To-and Fro-Murmurs

  • Patent ductus arteriosus
  • Ventricular septal defect with aortic regurgitation
  • Aortic stenosis with aortic regurgitation
  • Diastolic Murmurs
  • Mitral and tricuspid valve stenosis
  • Aortic and pulmonic valve endocarditis (inflammation of the inner layer of the heart)

In order to determine exactly what is causing the symptoms, your veterinarian must differentiate a wide range of abnormal heart sounds—split sounds, ejection sounds, gallop rhythms, and clicks, for example. He or she must differentiate between abnormal lung and heart sounds, and listen to see if timing of abnormal sound is correlated with respiration or heartbeat.
The location and radiation of the murmur, as well as the timing during cardiac cycle, is another way to determine the underlying cause. This can be accomplished by conducting a variety of tests, including chest radiographs (x-rays), Doppler studies (blood pressure), and echocardiography. A complete blood count, meanwhile is one of the preferred methods for confirming anemic murmurs.

Unless heart failure is evident, your cat will be treated as an outpatient. The course of treatment will be determined based on the associated clinical signs. Kittens with low grade murmurs, for example, may require little or no treatment and the murmur may resolve itself within six months. Routine diagnostic imaging is recommended for cats with murmurs.
Source URL; http.//www.petmd.com/cat/conditions.cardiovascular/c_ct_heart_murmur

Hypertrophic Cardiomyopathy in Cats

The heart has four chambers: two chambers at the top, the right and left atria; and two chambers on the bottom, the right and left ventricles. The left ventricle is responsible of receiving oxygenated blood from the lungs and pumping the blood out into the aortic valve, the main artery of the body, which feeds the oxygenated blood to all parts of the body. Hypertrophic cardiomyopathy (HCM) affects the left ventricle and its functional ability to pump blood into the aorta. The normal, healthy left ventricle is already thicker than the right ventricle owing to its greater workload in pumping blood out into the body. In hypertrophic cardiomyopathy, the muscle of the left ventricle is abnormally enlarged or thickened. A cat may have other diseases of the heart, but they will be independent of HCM.

There is an apparent genetic predisposition for this condition. Some families have had a high number of cases, particularly Maine coon cats, where a mutation that is associated with the disease was identified in one large family. The role of genetics has not been definitively determined in other families or breeds, although some association has been documented in American Shorthairs and Persians.

HCM occurs more often in cats five to seven years of age, although the age range reported cases ranges from three months to 17 years, with most cases affecting males. Heart murmurs in older cats are generally caused by hyperthyroidism or hypertension rather than HCM.
Symptoms and Types

  •  Loss of appetite (anorexia)
  •  Lethargy
  •  Weak pulse
  •  Difficulty breathing
  •  Short, rough, snapping breathing sounds (crackles)
  •  Abnormal heart sounds (i.e., muffles, galloping rhythm, murmurs)
  •  Inability to tolerate exercise or exertion
  •  Sudden hind-limb paralysis with cold limbs due to clot in the terminal aorta
  •  Bluish discoloration of foot pads and nailbeds (indicates a lack of oxygen flow to the legs)
  •  Collapse
  •  Sudden heart failure

The cause for HCM may remain unknown in many cases. However, genetic mutations and predispositions are known to head to HCM in cats. And though not a direct cause of the condition, hypertension and/or hyperthyroidism can further complicate HCM in cats.
Your veterinarian will need a thorough history of your cat’s health leading up to the onset of symptoms, including any information you have about your cat’s genetic background.
An electrocardiogram (or EKG) recording can be used to examine the electrical currents in the heart muscles, and may reveal any abnormalities in cardiac electrical conduction (which underlies the heart’s ability to contract/beat), and can also help your veterinarian to determine the origin of the abnormal heart rhythms, if they are present. However, and EKG may not be adequate for a definitive diagnosis. Radiograph and echocardiograph (ultrasound) imaging will be more useful for visually examining the heart for enlargement or thickening of the walls, or for thickening of the mitral valve (which controls the flow of blood between the left ventricle and the left atrium). Other conditions will need to be either ruled
out or confirmed before your doctor settles on HCM. There are two conditions, which are especially likely to mimic HCM that your cat will be checked for. Blood pressure will be checked in order to rule out hypertension, and the blood will be tested for high levels of thyroid hormones. Hyperthyroidism will exhibit many of the same symptoms as HCM, such as lethargy, shortness of breath and irregular heart rhythm.
If there is a diagnosis of HCM, your cat will be hospitalized for appropriate care, especially if it is suffering from congestive heart failure, a common outcome of this disease. Your cat will be placed in a quiet environment to minimize stress, and if it is having trouble breathing it will be given oxygen therapy.

There are several possible medications that can be used to treat HCM:

  •  Diltiazim to slow the heart rate, treat irregular heartbeats, and possibly reduce the enlargement in the left ventricle
  •  Beta blockers to slow the heart rate, correct irregular heartbeats, and control blockage of the blood flow. These are not used if the cat has congestive heart failure.
  •  Ace inhibitors, in cases with congestive heart failure, to improve the flow through the ventricle
  •  Aspirin to decrease risk of blood clots
  •  Warfarin to prevent blood clots
  •  Furosemide (diuretic) to remove excess fluid from the body
  •  Spironolactone (a diuretic used sometimes in conjunction with furosemide) for cats with congestive heart failure
  •  Nitroglycerin ointment, to improve flow by dilating (opening) the ventricle and arteries

Living and Management
The cat should be put on a sodium-restricted diet, especially if there is congestive heart failure, to keep the pressure in the blood stable. Providing a quiet and safe space for your cat, away from other pets and active children, is important to its recovery. Environmental stress may activate the nervous system, placing excess stress on the already overstressed left ventricle, and possibly lead to heart failure.
You will need to monitor your cat closely during the recovery period, watching for difficulty breathing, lethargy, weakness, lack of appetite, and painful hind-limb weakness or paralysis. Periodic diagnostic testing (such as repeat echocardiogram) and bloodwork will be necessary (to monitor kidney function and electrolytes).
Source URL: http://www.petmd.com/cat/conditions/cardiovascular/c_ct_cardiomyopathy_hypertrophic

proBNP Testing in Cats

The cat’s heart increases production and secretion of BNP, B-type natriuretic peptide hormone, in response to excessive stretching of heart muscle cells, which is common in many forms of heart disease and heart failure. The magnitude of the increase in circulating BNP is correlated to the severity of the underlying heart disease. A diagnostic test is available, the feline NT-proBNP, which can measure this hormone.

Cats with respiratory signs such as shortness of breath (dyspnea), rapid breathing (tachypnea), and cough may be associated with underlying heart disease such as cardiomyopathy and congestive heart failure, or a primary respiratory disease such as bronchitis/asthma, pneumonia, pleural effusion, and so on. At times it is unclear if the respiratory symptoms are related to cardiac (heart) or pulmonary (lung) disease, especially if the physical exam and chest x-rays are ambiguous. In such cases, a proBNP test may help guide further diagnostic testing and therapy. The proBNP is not a stand-alone test but can be valuable when included with other diagnostic testing such as chest x-rays and echocardiogram.

Treatment Explanation


Treatment for Hyperthyroidism in cats:

There are three options for treatment of hyperthyroidism. All three are identical treatment forms to those for human patients with hyperthyroidism.

Oral anti-thyroid medications

    This medication (methimazole) blocks the production of thyroid hormones by the thyroid gland. This oral medication does not cure hyperthyroidism, and is usually required twice daily (lifelong) to control the disease. Methimazole can be useful in the treatment of hyperthyroidism in cats but it is not an innocuous drug. Regularly scheduled blood tests are required to adjust dosages and to determine if potentially harmful side effects are present. Owners frequently find that oral administration of this drug to their cat is costly and difficult over time.


    Surgical removal of the thyroid tumor (s) is performed under general anesthesia. This procedure usually results in a return to normal thyroid function for the cat though the risk of anesthesia must be given careful consideration. If both lobes of the thyroid gland are not removed, approximately 70% of cats will eventually develop a functional benign tumor of the remaining tissue, requiring additional treatment or surgery.

    Alternatively, removing both thyroid lobes during the same surgery increases the risks of disturbing calcium metabolism, which is governed by the 4 small, adjacent parathyroid glands. Because affected patients are usually geriatric, and under-conditioned, they must be monitored for post-surgical side effects including low calcium levels (hypocalcemia), and kidney dysfunction. They are commonly hospitalized from 2-5 days. To lessen anesthetic and surgical risk to the patient, a cat may be required to undergo medical therapy with methimazole until physical condition improves. Occasionally, hyperthyroid cats are found to have functioning thyroid tumors in the chest cavity, where surgery is not feasible.

Radioiodine I-131

    Of the three treatment options, radioiodine is considered by many to be the treatment of choice for most hyperthyroid cats. Overall, radioiodine provides a simple, effective, and safe cure for cats with hyperthyroidism. This form of therapy has been used successfully for over 50 years in human medicine, and over 20 years in veterinary medicine. It requires no anesthesia and can be offered to medically stable patients, regardless of their age!

    How does it Work?

    Thyroid function requires the uptake of the element iodine in the body in order to produce normal thyroid hormones. If a radioactive form (I-131) of iodine is administered to hyperthyroid cats, it accumulates in thyroid tissue wherever it occurs in the body. Thyroid tumors accumulate the greatest amount of radioactive iodine. Once inside the tissue, the radioactive iodine emits radiation, which destroys the overactive thyroid cells.

    The radioactive iodine not trapped in the thyroid is excreted in the urine and to some degree in the feces. The amount of radioactivity emitted by the compound naturally decreases by half, every 8 days. Thus, the radioactivity remaining in the cat's thyroid tumor tissue will painlessly dissipate on its own. Normal thyroid tissue tends to be automatically protected from the effects of radioiodine since the uninvolved thyroid tissue is suppressed and receives only a small dose of radiation. As an added patient benefit, there is no injury risk to the adjacent parathyroid glands. The residual (normal) thyroid tissue resumes full function within 1-3 months after treatment. An average of 95-98% of I-131 treated cats are permanently and safely cured with a single injection!

    Is it Safe?

    "Radioactive" iodine, despite its somewhat scary title, is considered the "gold standard" for safety and efficacy in treating hyperthyroid cats. I-131 administration is a safe and effective treatment for feline hyperthyroidism. This therapy has been successful in large numbers of cats, and the only recognized deleterious side effect has been hypothyroidism (underactive thyroid gland). This occurs in an extremely small percentage of cats and almost never requires specific treatment. The greatest risks are to the doctors and staff who work in the thyroid unit on a long-term basis. However, with stringent safety regulations, protocols, and monitoring, this form of therapy can be safe for cats and the caregivers!

Radiotherapy: What happens to my cat?

On or before the day of admission, you and your cat will meet with a veterinary medical specialist at PVESC. Your cat will be thoroughly examined and the medical records will be reviewed. The doctor will discuss any admission tests required (which can be done at your general veterinary hospital or on-site at PVESC prior to treatment) to ensure that radioiodine therapy is the best option for your cat. The results of any tests performed at PVESC will be discussed with you before proceeding with treatment. These tests can include:

    * A complete blood count

    * A thyroid hormone level (T4 or free T4) to an outside lab

    * Serum biochemistry analysis

    * Urinalysis

    * Blood pressure

    * Full body radiograph

    * Cardiac Pro BNP test

    * Ultrasonography (cardiac ultrasound to evaluate function if needed)

If your cat is judged to be medically stable, he or she will be admitted to the radiotherapy unit within 24-48 hours of your appointment. The unit is specially constructed for this use and houses only cats that are receiving radioactive iodine.

The quiet accommodations include "Southwest" decor and housing in roomy and cheery cat condos (by Snyder Manufacturing, Inc.). These condos have separate bathrooms and shelves for snoozing. The unit includes windows for natural lighting, music, and heated floors. The patients enjoy watching patrons of our bird and squirrel feeders.

Once the dose of radioactive iodine for your cat has been determined, it is injected painlessly under the skin (subcutaneous) exactly like a routine vaccination.

From that point on, your cat need do nothing else but sleep, eat and play while the radiation dissipates to safe levels (usually 3-7 days). We like to spoil all our patients as much as safely permissible. This brief separation is likely to be harder for the owners than the patients!

Your cat will be monitored daily while in our care. By daily monitoring of your cat's radiation level, we can determine when this level has declined to that allowable by law. At this time, your cat can be released to you. You will be contacted daily with updates during your cat's stay in the radiotherapy unit. If you have questions or concerns, do not hesitate to call us.


Pre-Treatment Diagnostic Testing

Pre-Treatment Diagnostics

These diagnostic tests are required before your cat can be admitted for radioactive iodine therapy.  We recommend that these tests be completed at your regular veterinarian’s office one to two weeks before your radioactive iodine consultation.  If these tests have not been completed, they can be completed at Portland Veterinary Specialists at the time of your radioactive iodine therapy consultation.  

Lab work
      - CBC, Chemistry
      - SDMA
      - Urinalysis
      - Thyroid level

Blood Pressure

Whole-body radiograph    
      - Radiograph(s) can be emailed to PVESC if digital, or brought with you to your appointment

Admission Information


   1. You or your referring veterinarian may request an admission appointment.

   2. Anti-thyroid drugs (Tapazole, Methimazole, etc.) Should be discontinued 1-2 weeks prior to admission. Most other medications are allowable but should be discussed prior to the admission process.

   3. Food containing fish products should be discontinued 2 weeks prior to admission. Fish products have been found to prohibit the uptake of radioactive iodine.

   4. You are welcomed and encouraged to bring your cat's favorite foods and/or treats. We provide an ample, tasty feline menu as well.

   5. Cat toys may be kept with your cat but they cannot be returned.

   6. Unfortunately, the State of Maine, in accordance with the strict regulatory guidelines of the Nuclear Regulatory Commission cannot permit client visitation while cats are in the radiotherapy unit.

   7. Once admitted and treated with I-131, your cat cannot be released to you until his or her radioactivity levels drop to a specific range. In the extremely unlikely event that a patient dies from another illness while being housed in the I-131 unit, the remains must be held by us until radioactivity diminishes (eighty days).


Radioiodine therapy is considered the optimal treatment for cats with hyperthyroidism. It has an extremely high success rate and safety record and we are pleased to offer this state-of-the-art treatment.

The costs of therapy reflect costs associated with providing these services:

   1. Pre-admission consultation with a veterinary medical specialist

   2. Cost and administration of the radioactive iodine

   3. Hospitalization and patient care in the radiotherapy unit

   4. Litter, food, and patient monitoring with radiation monitoring equipment according to stringent state nuclear medicine regulatory guidelines

   5. Time and expertise of the staff

   6. Costs associated with nuclear regulatory licensing and adherence to strict safety guidelines for hospital personnel

   7. Radioactive waste-removal

The cost for treatment is $1500.00.  Pre-admission diagnostic tests are associated with separate fees.  These diagnostics may be completed at your primary care veterinary office or at PVESC and include such tests as radiographs, blood work (CBC Chemistry Electrolyte panel, T4, SDMA test), urinalysis and blood pressure.  Other tests, such as echocardiogram, may be recommended.  In the rare instance that your cat will require an increased dose of therapy, there will be an extra fee of $250.00 for cats that require more than 4 mCi of radioactive iodine for treatment due to the extra expense of the therapy and the extra hospitalization that is required. 


Admission Agreement


Owner: _________________________

Address: ________________________

Phone: (Day)____________________





Cat's Name: __________________

Age: _____ Breed: ______ Sex: ______

Color/Markings: ___________________



Referring Veterinarian: _______________________________________

Referring hospital/clinic: ______________________________________
Consent to Treat

I authorize Dr. Gail Mason to hospitalize and treat the above-described cat with radioactive iodine (1-131). I understand that my cat will remain at this facility (PVESC) after administration of radioiodine until the radiation levels have decreased sufficiently to permit release of my cat. Until this time, no visitation is permissible for human safety reasons. The radiation levels permitted are determined by the State of Maine radiation safety guidelines and regulations.

I understand that:

    * My cat will be medically evaluated (including blood/urine tests, radiographs, and ultrasonography) to assess overall health status and eligibility for treatment.
    * Though the radioiodine treatment is successful with one treatment 90-95% of the time, outcomes cannot be guaranteed. For any cats requiring re-treatment at PVESC, the cost will be one-half the original amount.
    * Rarely, a small percentage of cats (<5%) develop an under-active thyroid (hypothyroidism) within a few months after treatment. This situation would require daily thyroid supplementation.

In the event of an emergency, I authorize the veterinarians at PVESC to render such medical and/or surgical treatment as deemed necessary, and I accept financial responsibility for costs incurred.

I agree to follow discharge instructions that are provided to me and understand that pregnant women and children younger than eighteen should not have direct exposure to my treated cat for 2 weeks following hospital release.


Signature of Owner______________________________ Date_____________

Discharge Instructions

Discharge instructions for owners of radiotherapy-treated cats:

For the first two weeks please follow these detailed home instructions for handling your cat and litter waste.

Please note that if you cannot or will not follow these instructions, you must notify us, and we may need to keep your cat hospitalized for additional time before release (additional fees apply).

The thyroid hormone level continues to decline for 30 to 60 days after treatment. During this time, the symptoms of hyperthyroidism are expected to abate. Gradual weight gain and return to healthy body condition are expected. If your cat is showing signs of illness or depression, please contact PVESC.

Upon discharge from PVESC (after an average of 4 to 7 days after treatment), treated cats will still be excreting radioiodine in their urine, saliva and feces. This radioiodine is in a form that can be taken up by the human thyroid where it may cause damage. Even through the level of radioactivity is much lower than the level at which human patients are released from the hospital, you must exercise caution during this period. The remaining radioactivity will be gradually eliminated from the cat over the next 2 to 4 weeks.

1. Treated cats must remain indoors only for two weeks after discharge.

2. Pregnant women, children under eighteen and people with immune mediated diseases should not have any contact with the cat or litter pan for two weeks.

3. Prolonged close contact with your cat (under 3 to 6 feet) must be avoided during this time. Limit visits to 20 minutes per session. Visit and pet your cat briefly, but do not allow the cat to sleep on your bed with you. Avoid contact with urine and saliva and do not allow the cat to sleep on your bedding.

4. Foods containing fish products can be reinstituted post-treatment.

5. Use disposable litter pan liners and plastic gloves to minimize handling of litter/waste.

6. Wash your hands after handling your cat, its food dishes and litter pan.

7. There is no need to quarantine your cat from other pets in the household.

8. If your cat must be seen by a veterinarian before the end of the 2-week quarantine, please alert PVESC.

While the amount of radioactive material remaining in your cat’s body is low, it is prudent to follow the above instructions exactly. If this is not possible, please consider boarding your cat with PVESC during the quarantine period (additional fees apply).

Waste Disposal

Disposal of litter pan contents:

If your home is on a public sewer system:

  1. Use scoopable/flushable litter such a “World’s Best Cat Litter” or Swheat”

  2. Wear protective gloves (such as dishwashing gloves), scoop your litter pan twice per day and flush the waste down the toilet.

  3. At the end of the two-week quarantine, flush all remaining litter down the toilet. The litter pan and scoop can be washed with soapy water and flushed down the toilet; it’s not necessary to save these items for any extended period or to discard them.

  4. This is the approved method of the State of Nuclear Regulatory Commissions.

If your home has a private septic system or if you have a public sewer and choose not to flush it:

  1. Your cat’s litter box must be scooped twice per day.

  2. Wear protective gloves (such as dishwashing gloves) and place the waste in a Ziploc or tie bag, be sure to double-bag the litter and excretions, then place the bag in a plastic tote with a locking lid that has been lined with a large garbage bag. This tote should be stored outside and away from small children, other pets and wild animals.

  3. At the end of the two-week quarantine, add all of the remaining litter from the boxes to the trash bag in the outside tote, tie the bag and leave all waste until the 80-day mark on your calendar.

  4. The litter pan and scoop can be stored with the trash bag in the tote for 80 days. It can then either be thrown out or washed and reused.

  5. When it is time to discard the waste, simply remove the large garbage bag from the tote and dispose of it as you would your household trash. The tote itself may be disposed of separately or can be rinsed out and reused.

Follow Up

We would like to recheck your cat’s progress in 4 to 6 weeks. This includes a physical examination, thyroid level (T4), renal panel with SDMA, electrolytes and body weight. If you prefer to see your primary care veterinarian for this, please have the results forwarded to PVESC.

Waste Disposal

Disposal of Litter Pan Contents
If your home is on public sewer use flushable litter. To dispose of your cat's urine and feces during its first 2 weeks post-treatment, scoop the soiled litter daily and flush it down the toilet. This is the approved method of the State of Nuclear Regulatory Commissions. If you refuse to follow this method or, your home has a private septic system, you must take these steps:

   1. For the first 14 days after your cat returns home from receiving I-131 therapy, put on your gloves, use your litter scoop to drop all soiled litter into a Ziploc (or similar) bag. Zip it shut. Place this bag in the second Ziploc (or similar) bag and zip it shut.

   2. Place the double-bagged litter, feces and urine in a large Tupperware (or similar) type container, lined with a trash bag, and close it with a tightly locking lid.

   3. Follow this process for 14 days, placing all double-bagged litter, feces and urine in the Tupperware (or similar) container, and lock the lid after each addition to the container.

   4. Mark on your calendar 94 days after the date of discharge from our facility for the stored litter to be discarded.

   5. During the time you store the container, place it outside where it cannot be reached by small children, pets, wild animals, etc, or in a basement or garage. Do not place it in occupied areas.

   6. At the end of the second week, put on your gloves and, in one step, pick up the edges of the litter liner containing any remaining litter, tie them together and place it with the litter you have collected over the previous two weeks. Dispose of your gloves, and wash or dispose of your litter scoop in the outside trash. If you have been unable to successfully use a litter pan liner, dispose of your litter pan as well. You may now return to your normal litter disposal routine.

   7. 94 days after discharge from our facility, open the container, pick up the trash bag lining it, and place the bag in your outside trash. Do not bury the litter or use it in the garden. You may dispose of the container separately.

Patient Follow-up

What will Treatment be like for my cat?

The ideal goal of 1-131 therapy is to restore normal thyroid function with a single dose of radiation without permanently damaging normal thyroid tissue. Most hyperthyroid cats treated with 1-131 are cured by a single injection-No surgery! No anesthesia! No medication!

Successful treatment results in normal thyroid hormone levels within 2 weeks of treatment in 70-8O% of cats. Over 90% of treated cats reach normal hormone levels within 3 months post-treatment. Cats often feel better within days of treatment and most owners can expect gradual and steady health recovery within 2 months.


Medical Follow-up

Copies of all pertinent medical records and test results regarding your cat's treatment will be forwarded to your primary care veterinarian. We recommend a recheck examination, thyroid (T4) level and kidney (renal) profile with your veterinarian 2-3 months after I-131 treatment. Please have the results forwarded to PVESC.


Ultrasound allows diagnostic tests to be performed with the aid of safe sound waves. The sound waves bounce off the animal’s internal organs (or a mass), and are decoded into an image on the monitor. This is a powerful and versatile technique in which a skilled ultrasonographer can see, measure, and assess the health of many internal organs. In many cases, it can preclude the need for major surgery. 

If a tumor is suspected, often its presence can be confirmed, its tissue biopsied, and a fairly accurate assessment can be made as to whether or not the tumor is operable. This assists the veterinary surgeon in planning and preparing for the surgery.  Ultrasound is a rewarding technique to evaluate the liver, spleen, adrenal glands, pancreas, kidneys, prostate, bladder, and uterus. It is not, however, the primary tool used in disease of the stomach or intestines.

Preparation for the Technique: The ultrasound examination itself is virtually risk free in most cases. It can usually be done without anesthesia or sedation and requires about twenty to thirty minutes to complete. A review of your pet’s medical records, tests, and a physical examination will precede the ultrasound. Patients are fasted at least 12 hours prior to the ultrasound to ensure a proper view of each organ system. Depending on the type of ultrasound, your pet's ultrasound may be completed while you wait, or your pet may be admitted to our hospital for a few hours. If a biopsy is needed, sedation and/or anesthesia (brief) may be required.  Biopsies can be completed with ultrasound guided instruments. The tissues are sent by overnight courier to board certified pathologists and the results are usually received in three to five business days.


Echocardiography is specialized ultrasound of the heart. The heart’s action and functions can be studied in detail with an echocardiogram. Several sets of measurements can be made which aid in the determination of type and severity of an animal’s heart dysfunction. This information aids veterinarians in prescribing medications that can alleviate signs and symptoms of heart disease. It can also be used as a monitoring technique. Generally, no anesthesia is required, and the echocardiogram is completed during your office visit. Additional information (a data base) may consist of chest x-rays, an electrocardiogram, and analysis of any fluid present in the chest cavity. Patients are often referred because of known or suspected heart disease, fluid around the heart or in the chest cavity, evaluation of heart murmurs, and suspected chest or heart tumors.


Ultrasound is a safe technique to determine if an animal is pregnant. It can be used as early as 21 days after the last breeding date. An estimation can often be given as to the number of embryos present. Ultrasound can also be used to visualize the reproductive organs which include the uterus and ovaries in the female, and the prostate/testes in the male animal. This is generally a short, out-patient visit.

Cranial Cruciate Ligament Disease

Dr. April Guille

Damage to the cranial cruciate ligament (CCL) is one of the most common orthopedic injuries in dogs.  The majority of dogs have secondary degenerative changes in the ligament that lead to rupture.  The causes for cranial cruciate ligament degeneration are multifactorial (a combination of genetic and environmental factors).  Trauma leading to rupture is seen in a smaller percentage of patients.

The cranial cruciate ligament is a major stabilizer in the stifle (knee) joint, both limiting forward motion of the tibia in relation to the femur (termed cranial thrust) and internal rotation in the joint.  Unfortunately, the torn ligament will not heal itself and partial tears almost always progress to complete rupture of the ligament. After rupture, the stifle joint becomes unstable, leading to inflammation, pain, meniscal injury, fibrosis, and osteoarthritis in the joint. 

Clinical signs:  CCL rupture causes pain and lameness in the affected leg.  Dogs with partial tears may initially improve after restriction of activity, but the lameness will typically return as they continue to tear their ligament, leading to a cyclical course of lameness and improvement with rest.  The lameness often becomes progressively worse to the point of a permanent lameness of varying degrees.  Dogs can also become very lame after tearing their medial meniscus.  Other clinical signs include stiffness, sitting with the leg out to the side, muscle atrophy, decreased activity, and occasionally, owners may hear an audible “click” if the medial meniscus is torn.

Diagnosis:  The diagnosis is based on history, physical exam, and radiographic findings.  On physical exam, we will check the stifle for drawer motion, or an abnormal forward motion of the tibia in relation to the femur, and cranial thrust.  Joint effusion (swelling) is present in the joint and long-standing ruptures will have secondary fibrosis around the joint, especially on the inner aspect, termed medial buttress.    The cruciate ligament is not visible on plain radiographs, but radiographs are taken to rule out other causes of the lameness, evaluate the joint for evidence of effusion and osteoarthritis, and pre-operative planning.  Occasionally, some dogs can be very tense, and sedation will allow better evaluation of the stifle for abnormal motion.


Medical Management:
  Cruciate ruptures are best handled with surgery (see below).  But in addition to surgery, medical management is used to assist with the joint health, manage osteoarthritis, and assist with the recovery from surgery.  This may include but is not limited to: glucosamine and chondroitin supplementation, non-steroidal ant-inflammatories, physical therapy, and alternative therapies such as laser or acupuncture treatments.  Please see the page on managing osteoarthritis. 

Surgical Treatment:  Although the arthritis in the joint cannot be reversed, early surgical intervention may mitigate the progression of osteoarthritis and therefore improve overall long-term function of the joint.  Surgical techniques can broadly be divided into intracapsular (within the joint) and extracapsular (outside of the joint) repair.  Regardless of the technique used, the joint is entered and the medial meniscus is evaluated at the time of surgery.  The two menisci in the joint act as a cushion and shock absorber.  A portion of the medial (inner) meniscus can become pinched and torn due to the abnormal motion present in a CCL deficient stifle joint.  This torn piece, if present, is removed. 

Below is a summary of the three surgical treatments we use here at PVS for treatment of CCL rupture.  We will discuss these options with you at the time of your appointment and what might be best suited to you and your pet’s needs.

Lateral Fabellar Suture Technique

After closure of the joint capsule, two sutures are passed around a small bone (lateral fabella) on the back side of the femurand through a bone tunnel created in the top of tibia.  They are then tied to an appropriate tension.  This orientation mimics the cranial cruciate ligament, providing temporary stability.  The ultimate stability is provided by scar tissue that surrounds the joint.    

Patients that receive this surgery typically take a little longer (up to 6 months) to be at their best function post-operatively.  There is a subset of larger dogs, especially active dogs, who may not do as well with this surgery compared with the biomechanical stabilizations (discussed below). 

Tibial Plateau Leveling Osteotomy (TPLO)  

The TPLO is a form of biomechanical stabilization that eliminates the need for the cranial cruciate ligament by altering the forces acting on the stifle joint and preventing cranial thrust of the tibia.   After evaluation of the menisci, the joint is closed and the tibial bone is cut.  The bone is rotated several millimeters and plated in a new position.  These measurements are determined based on preoperative evaluation of specific radiographic positions.  The tibia heals in its new orientation, “leveling” the tibial slope and stabilizing the stifle joint. 

Tibial Tuberosity Advancement (TTA)

The TTA is another form of biomechanical stabilization of the stifle joint.  Like the TPLO, the TTA eliminates cranial thrust by cutting the tibial tuberosity and repositioning it with a spacer and a titanium plate.  The measurements for the implants are determined on specific pre-operative radiographic views. 


Which surgery is right for your pet?

While all three surgeries help improve the lives of our pets, many factors determine which specific surgery is best for you and your pet.  We generally find that dogs undergoing a biomechanical stabilization (TTA or TPLO) will have a better short-term and likely long-term recovery.  However both of these surgeries, while approximately the same price, will cost more than the lateral fabellar suture technique due to the required equipment and expertise.  Of the two biomechanical surgeries, the TTA is generally preferred by Dr. Guille.  In comparison with the TPLO, the TTA is less invasive, requires a shorter anesthesia time, patients typically make a quicker recovery, and the complications are usually less serious in nature if they occur.  Studies have also shown that of the three procedures, the TTA is the only one to restore the contact mechanics in the joint back to “normal”, or what existed prior to rupture of the cruciate.  The TPLO, however, is able to be used in a broader category of bone conformations, so some dogs are not suited to the TTA procedure.  The discussion of the pros and cons of each surgery, along with the recommendation for your pet, will be determined at the time of your consultation.  Specific radiographic views may be required prior to surgery to make the final determination.


Osteoarthritis afflicts a large number of pets in the United States.  It is a slowly progressive disease that results in the degeneration of cartilage, fibrosis of the soft tissues surrounding the joint and new bone formation.  Osteoarthritis can be the end result of several initiating causes, including congenital problems, traumatic events, certain diseases, or wear and tear on the joints.  Osteoarthritis in animals is caused more often by an initiating cause than by normal aging and degeneration of the cartilage.  Whatever the inciting cause, initial cartilage degradation results in the release of inflammatory substances which further contribute to cartilage breakdown.  A vicious cycle ensues, resulting in cartilage loss, hardening of the underlying bone, fibrosis of the surrounding tissues, formation of new bone called osteophytes, and inflammation of the lining of the joint.  The end result for your pet is pain and a loss of function in the affected joint or joints.

Some inciting causes of osteoarthritis:
-    Cranial cruciate rupture
-    Patellar luxations
-    Hip dysplasia
-    Fractures entering the joint
-    Joint conditions such as osteochondritis dissecans, fragmented medial coronoid process, ununited anconeal process and elbow incongruency
-    Inflammatory joint diseases
-    Septic arthritis

Signs of arthritis include:
-    Reluctance to take walks
-    Stiffness  
-    Difficulty climbing stairs, climbing in the car, on the bed or a sofa
-    Difficulty rising from rest
-    Limping
-    Acting withdrawn, spending less time playing with family
-    Soreness when touched  
-    Rarely, aggression

Once a joint has progressed to arthritis, we cannot reverse the changes present in the joint.  However there are several options to help manage your pet’s discomfort, thus improving their quality of life.

Weight Reduction (if applicable):   It is very important that dogs and cats afflicted with osteoarthritis maintain an ideal body weight.  The extra weight carried by an overweight or obese animal places additional stress on the joints. In animals at an ideal body weight, you should easily be able to palpate their ribs through a minimal layer of fat and your pet should have a nice “waistline tuck” behind the ribs when viewed from above and the side. If you have any questions on body condition or diet, please consult a veterinarian.  Weight loss for overweight osteoarthritic pets is one of the easiest and important things you can to improve your pet’s comfort.  

Moderate Daily Exercise:   Arthritic joints function better when they are mobilized during low-impact exercise on a daily basis.  Swimming is an excellent option.  Leash walking or controlled jogging are also acceptable.  Important things to remember are avoiding high impact activities, especially things like chasing a ball, which has sudden stops and turns.  Also try to avoid having your pet receive no exercise for several days followed by strenuous activity.

Nutraceuticals:   Glucosamine and Chondroitin are two examples of nutraceuticals and they are often found in combination tablets.  Glucosamine and chondroitin are molecules normally found in cartilage.  Both substances may support cartilage structure, prevent further deterioration in the joint, suppress inflammation, and reduce free radical damage.   Using both in combination has been shown to slow down cartilage damage better than using either of these products alone.  It is important to remember that nutraceuticals are not drugs, and are therefore not directly regulated by the Food and Drug Administration.  Independent studies have shown that many human products do not contain the amounts of glucosamine and chondroitin stated on the label, and some may even contain substances harmful to the health of your pet.  (In fact, only 16% of products that were studied met the overall claims on their label, according to one study).  For this reason, we recommend using veterinary approved products that undergo routine testing to ensure the content of the product matches the label.  Dasuquin and Cosequin are two such products.  The major difference between these two products is that Dasuquin includes avocado and soybean unsaponifiables, which have also been shown in multiple studies to support joint health.

Omega Fatty 3 Acids:   Studies have shown that Omega Fatty 3 Acids, typically found in fish oil, can reduce joint inflammation.  Fish oils are typically a mixture of different fatty acids (FA).  Recent research by Hills shows that the EPA strength is the most important to determine dosing.  They recommend 50-100 mg EPA per kilogram of body weight per day.  Fish oil capsules can be stored in the freezer to reduce “fish breath”.  Some people prefer to simplify matters by feeding a diet that already contains fish oil, such as Hills j/d diet.  This is a prescription diet and can typically be purchased through your regular veterinarian’s office.

Non-steroidal Anti-Inflammatories (NSAIDs):   These medications are commonly prescribed for arthritis pain and include the drugs Rimadyl (carprofen), Metacam (meloxicam), Previcox (firocoxib), and Deramaxx (deracoxib), among others.  These medications are similar to humans taking ibuprofen or aspirin; however, dogs can be very sensitive to the human formulations and should not be given any human non-steroidal anti-inflammatories without a veterinarian’s guidance.  (Aspirin also inhibits platelet function and should be stopped 2 weeks prior to any planned surgery.)  NSAIDs both reduce inflammation and provide pain relief.  A veterinary formulation is a good medication to have on hand and give to your pet prior to activities you know may exacerbate the arthritis or if your pet seems to be having a sore day.  The most common side effects of NSAIDs are gastrointestinal in nature.  If you notice any vomiting, diarrhea, inappetence lasting greater than 24 hours, or black tarry stools, please stop the medication and contact your veterinarian.  In rare cases, these medications can cause bleeding or perforating ulcers.  These medications are not routinely used in pets with liver or kidney problems, or pets who are receiving steroids.  Patients on long-term routine usage of NSAIDs should have bloodwork performed every 6 months or according to your veterinarian’s recommendation to confirm the liver and kidneys are functioning well.  Very rarely, idiosyncratic liver reactions to NSAIDs have been reported, leading to serious illness or death.

Acupuncture:   Acupuncture has a long history of being useful for managing pain.  It can serve well as a complimentary treatment for dogs with pain and mobility issues due to osteoarthritis.  Dr. Gary Stuer provides acupuncture services at PVS every Wednesday. (read more on acupuncture)

Laser Therapy:   Treating arthritis pain is one of the many uses for laser therapy.  Laser therapy is a noninvasive procedure that uses light to stimulate cells, increasing blood circulation, decreasing swelling, and speeding up healing. At the correct laser wavelength, pain signals are reduced and nerve sensitivity decreases. The procedure also releases endorphins, which are natural painkillers.  Laser therapy it is not recommended for animals with cancer because the device can stimulate blood flow to cancer cells.  Light is absorbed into the cells during laser therapy. The process, known as photobiotherapy, stimulates protein synthesis and cell metabolism, which improves cell health and functionality.  The therapy can take as little as 5 minutes or up to about a half hour for bigger dogs with multiple treatment areas.  Chronic, or long-standing problems, may take several treatments before noticeable results are seen.  Treatments should also be done more frequently in the beginning (2-3 times a week) prior to going on a “maintenance” schedule.  Therefore, laser treatments are often sold in packages of 6 treatments.  Please consult Dr. Guille for further information on the treatments and if it would be right for your pet.

Physical Therapy:   Physical therapy is used extensively in human patients with osteoarthritis and can be of benefit in our canine and feline patients as well.  Treatments such as heat and cold, massage therapy, and passive joint manipulation can all help. In addition, specific strengthening activities/exercises can be very beneficial to some arthritic patients.  Most programs are best under the direct supervision of a certified canine rehabilitation therapist (CCRT).  The distance that most people live from a CCRT can limit the amount of treatments performed directly by the physical therapist, but even one consultation can be very helpful by showing you exercises you can perform at home to help with your pet’s condition. 

Injectable Chondroprotective Agent:  There are two separate injectable products that have been used for arthritic joint pain.  One is a formulation of polysulfated glycosaminoglycans (PSGAGs) and goes under the trade name of Adequan.  The exact mechanism of action is not known, and studies have shown conflicting results.  It is usually injected in the muscle twice weekly for 3-4 weeks.  This medication is best suited for joints where there is the chance the cartilage will heal (i.e. a fracture in the joint).  Otherwise, the benefit is likely limited to pain control.  We often use this medication when other treatments are not enough.  Another injectable agent is hyaluronan, which is naturally found in the joint and is given as an injection directly into the affected joint.  It is often administered every 2 weeks for three injections.  Unfortunately, the cost can be expensive, since your pet must be sedated and the joint sterilely prepped prior to injection.  About half of dogs respond positively to the injection.  

Surgery:   In certain situations, surgery may be applicable to help with osteoarthritic pets.  This can be determined during a consultation with a veterinary surgeon.

Stem Cell Therapy:   Stem cell therapy is a relatively new treatment modality in veterinary medicine.  The thought process behind the treatment is to gather stem cells from the patient’s own body for the repair or replacement of damaged or diseased tissue.  The typical procedure is as follows:
-    Harvesting of the patient’s fat through a surgical procedure under anesthesia  
-    The fat is then sent to a lab overnight where the stem cells are harvested
-    After a day, the stem cells are sent back by the lab
-    48 hours after the initial surgery, the patient is sedated for injection into the affected joints and/or IV injection, depending on the individual case
This procedure is typically reserved for use after other treatments have failed, because the cost can be much higher than other treatments.  If you are interested in the procedure for your pet, please consult Dr. Guille for further information.  The procedure will not be performed the day of the consultation, as preplanning with the laboratory is required.

The key points in managing osteoarthritis are remembering it is a disease that can be managed, not cured, and that there are many different options to help manage your pet’s discomfort and provide the best quality of life possible.

Spontaneous Chronic Corneal Epithelial Defects (SCCEDs)

 By: Rachel Mathes, DVM, MS, DACVO


Spontaneous chronic corneal epithelial defects or so called “SCCED” lesions are superficial corneal ulcers that occur in middle-aged, usually large breed dogs, although they may be seen in any breed (1).  SCCED lesions, also known as non-healing ulcers, “indolent” ulcers and “Boxer” ulcers, have a typical clinical presentation and appear as large superficial corneal ulcers with marked epithelial lipping (1,2).The epithelial lip may be seen using focal illumination (e.g. Finhoff transilluminator) or may be highlighted with fluorescein staining with the stain noted to migrate under the epithelial lip. Once the loose epithelium is debrided, the ulcer is often much larger than what is seen prior to debridement. These ulcers may also be associated with dramatic secondary corneal vascularization and granulation tissue.


Although the exact cause of SCCEDs is not known, this defect is thought to be an abnormality in the adhesive mechanism of the corneal epithelium to the stroma (1,3). Upregulation of matrix metalloproteinase (MMP) 2 and 9 is not a characteristic of these lesions (4). An acellular, hyaline membrane is found on histopathology in the ulcer bed and is thought to be contributory in preventing normal epithelial adhesion during the healing process (1).  Although uncommonly these ulcers may become secondarily infected and prophylactic antibiotic therapy is warranted, bacterial infections are not causative in these cases. Aggressive antibiotic therapy or periodic switching of topical antibiotics will have no effect on these ulcers and may potentiate resistant bacterial infection.


Treatment for SCCEDs is aimed at creating very superficial stromal abrasion mechanically. Occasionally, debridement of the ulcer with a sterile cotton tipped swab will effect healing. More commonly, however, a more aggressive treatment such as a diamond burr keratectomy or grid keratotomy is required to initiate healing (3.5). Grid keratotomies cause more stromal damage and resultant astigmatism than diamond burr keratectomies (5). Recent studies have shown a very high success rate after diamond burr keratectomy with 70% healed at 1 week and 92.5% healed at 2 weeks (3). Topical chondroitin sulfate may also be beneficial in promoting epithelial adhesion and may decrease surface shearing forces (5). 

 Picture A  Picture B


&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;  &nbsp;Image &nbsp;( A )

                       Image  ( A )

&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Image ( B )

                     Image ( B )

Typical SCCED lesions are pictured. Not the prominent irregular, raised corneal granulation tissue and epithelial margin (arrow) with fluorescein stain migrating under the epithelial lip (A). A well demarcated focally extensive superficial ulcer is present with an epithelial margin after debridement (B).  


1. Bentley, et al. Spontaneous chronic corneal epithelial defects in dogs: a review. J Am Anim Hosp Assoc. 2005: 41; 158-65.

2. Ledbetter, et al. Efficacy of two chondroitin sulfate ophthalmic solutions in the therapy of spontaneous chronic corneal epithelial defects and ulcerative keratitis associated with bullous keratopathy in dogs. Vet Ophthalmol. 2006: 2; 77-87.

3. Gosling, et al. Management of spontaneous chronic corneal epithelial defects in dogs with diamond burr debridement and placement of a bandage contact lens. Vet Ophthalmol. 23 April 2012, online early view.

4. Carter, et al. Expression of matrix metalloproteinase 2 and 9 in experimentally wounded canine corneas and spontaneous chronic corneal epithelial defects. Cornea. 2007: 10; 1213-1219.

5. Da Silva, et al. Histologic evaluation of the immediate effects of diamond burr debridement in experimental superficial corneal wounds in dogs. Vet Ophthalmol. 2011: 4; 285-291.

Limbal Melanomas

By: Rachel Mathes, DVM, MS, Diplomate ACVO

Facts about Limbal Melanomas:

  • Benign, slow growing tumors in dogs and cats
  • Very responsive to a variety of therapies
  • Low rate of metastasis
  • Low rate of recurrence with treatment
  • Early referral recommended

Limbal melanomas are benign, slowly growing tumors of limbal melanocytic origin. These tumors typically occur along the dorsomedial to ventrolateral limbal arc of the globe at the corneal and scleral junction.1 A bimodal age distribution has been described with a peak occurrence at 3-4yrs of age and 7-10yrs of age in dogs (1,2). These tumors are thought to have an inherited basis as Golden Retrievers are four times more likely and Labradors are three times more likely to develop this compared to other breeds (1). Though benign, limbal melanomas may become globe-threatening with growth due to local invasion. Often, secondary keratitis with corneal lipid deposition will occur as a result of the tumor presence (2,3).  While these tumors are less common in cats, they may occur and have a similar clinical course as canine melanomas (3).  Feline and canine limbal melanomas are amenable to a variety of therapies including surgical debulking with a combined keratectomy and sclerectomy, cryotherapy, laser photocoagulation, radiation and surgery with homologous and autologous grafting (2,3,4). In one recent study, only 1 our of 30 tumors recurred after a combination therapy protocol (2). In addition, the incidence of side effects from surgery was low with less than 10% of complications being potentially globe threatening (2).  After laser photocoagulation, a low recurrence was reported with 1 out of 15 masses recurring at 3 months and 2 out of 15 recurring at one year. Twelve of the fifteen tumors did not recur (3). 

Long term control and vision are attainable and reasonable goals with appropriate therapy. Early referral is recommended to preserve vision and globe integrity.

A dorsomedial limbal melanoma in the left eye is pictured. The mass is heavily pigmented, raised, irregular and well-demarcated with an arc of white corneal lipid at the leading edge.

Inherited Eye Disease and OFA Certification

By Rachel Mathes, DVM, MS, DACVO

Inherited ocular disease in purebred dogs is an important cause of potentially preventable ocular conditions. These conditions range from irritating (e.g. distichia, lacrimal micropuncta) to vision-threatening (e.g. PRA, micropapilla, cataracts). This is a large group of ocular diseases that are typically characterized by autosomal recessive genetic transmission. They are often marked by a clinical onset later in life. These characteristics make prevention through selective breeding and early detection difficult. In addition, many of these genetic traits are so common in the purebred dog population that complete omission of carrier dogs in the breeding pool would significantly narrow the gene pool for particular breeds and would not be warranted or reasonable due to possible selection for other abnormal traits. Recently, a change was made to the ophthalmic certifying agency supported by the American College of Veterinary Ophthalmologists (ACVO). While the Canine Eye Registry Foundation (CERF) still exists, the ACVO has partnered with the Orthopedic Foundation for Animals (OFA) to provide a centralized database of eye examinations performed by board-certified veterinary ophthalmologists on dogs in the United States.

Breeders are encouraged to have any canine purebred breeding pair certified with the OFA Eye Database. Eye examinations are performed by a Diplomate of the American College of Veterinary Ophthalomologists and information from the eye examination is submitted to the OFA. The OFA recommends submission of the eye examination forms even if the dog is not “clear” of inherited ocular disease. Submission into the database is complimentary for any dog with a “failing” grade (ocular condition known to be inherited in which breeding is not recommended). A nominal fee applies to certify dogs deemed free of clinical inherited ocular disease or dogs in which a diagnosis is made in which a designation of “breeder option” has been given. An example of this would include Cavalier King Charles Spaniels examined and noted to have distichiasis. Because this trait is common in the breed and does not typically cause clinical ophthalmic pathology, the breeder has the option to breed the dog, even though it is affected with a known inherited ocular trait. While it cannot be determined if a “normal” dog is a carrier for a specific trait based on ophthalmic examination, information on affected and unaffected dogs is valuable for many reasons. Ongoing genetic research and data collection is vital for prevention of vision-threatening inherited ocular conditions, such as PRA (progressive retinal atrophy) (see Figure A and B). Portland Veterinary Specialists offers OFA Eye Canine Registry examinations for all purebred dogs.


&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;  &nbsp;Picture ( A )

                     Picture ( A )

&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Picture &nbsp;( B )

                   Picture  ( B )

Picture legend:

A normal indirect fundic photograph is depicted (A). Note the 15-20 prominent arterioles emerging from the optic disc with three main retinal venules (larger and more tortuous than the arterioles). The vessels extend to the fundic periphery. A patient with PRA is depicted (B). There is vascular attenuation manifested by loss of visible arterioles and lack of vascular extension to the fundic periphery. There is also generalized tapetal hyperreflectivity.