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 PVS. 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 PVS prior to treatment) to ensure that radioiodine therapy is the best option for your cat. The results of any tests performed at PVS 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 5-8 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 PVS 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 total cost for consultation and I-131 treatment alone is $1350.00. Pre-admission diagnostic tests that are deemed necessary or recommended are associated with separate fees.  These diagnostics may be completed at your primary care veterinary office or at PVS and include such tests as echocardiogram, radiographs, blood work (CBC Chemistry Electrolyte panel, T4, SDMA test), urinalysis and blood pressure. 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 5 mCi of radioactive iodine for treatment due to the extra expense of the therapy and the extra hospitalization that is required.  

Charges for the initial pre-admission consultation and any tests completed are due at the time of the consultation appointment, and the remainder of the balance is due at the time of admission for treatment.

Post treatment progress examination and blood work is recommended four to six weeks after therapy. This examination and blood work may be completed at your primary veterinary office or at PVS.

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 (PVS) 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 PVS, 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 PVS 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:

Upon discharge from PVS (average of 5-7 days after treatment), treated cats will still be excreting a small amount of radioiodine in their urine and feces. Even though the level of radioactivity is very low (much lower than the level at which human patients are discharged from the hospital), you must still exercise caution during this period. The remaining radioactivity will be gradually eliminated from the cat over the next 2-4 weeks.

   1. Treated cats must remain indoors (only) for 2 weeks after discharge.
   2. Pregnant women and children under eighteen should not have any direct contact with the cat or litter pan for 2 weeks.
   3. Prolonged close contact with your cat (<3-6 feet) must be avoided during this time. Visit and pet your cat briefly, but do not allow the cat to sit on your lap or sleep with you. The cat should be confined to an unoccupied room at night. Avoid contact with urine and saliva and do not allow the cat to sleep on your bedding.
   4. Foods containing fish products should continue to be withheld until the T4 is rechecked in 4-6 weeks post-treatment.
   5. Use disposable litter pan liners or plastic gloves to minimize handling of litter/waste.
   6. Wash 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 us.

The radio pharmaceutical that your cat received is beneficial to it. For perspective, the amount of radiation you might receive from your cat would be roughly equivalent to that received when you fly cross-country round trip. While the amount of radiation remaining in your cat's body is extremely low, it is prudent to follow the above instructions exactly. If this is not possible, please consider boarding your cat with us during the quarantine period (additional fees apply).

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 PVS.


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


                       Image  ( A )

                       Image  ( A )

                     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.


                     Picture ( A )

                     Picture ( A )

                   Picture  ( 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.


Dr. Rachel Mathes, DVM, MS, Diplomate ACVO

 Facts about Glaucoma

• Secondary glaucoma more common than primary glaucoma

• Females overrepresented 2:1 for primary glaucoma

• Primary glaucoma typically associated with iridocorneal angle closure and increased intraocular pressure during middle age (6-8 years old)

• Canine glaucoma tends to be aggressive

• Feline glaucoma is almost exclusively secondary

• Concurrent institution of prophylactic therapy for the contralateral eye should be instituted if an eye is enucleated for primary glaucoma

• Imperative to address IOP spikes immediately as they may quickly cause complete blindness

Glaucoma is a term used to describe a group of diseases that cause elevated, often severely, intraocular pressure. This condition is very painful and treatment is aimed not only at preservation of vision, but also for pain management. The pain of glaucoma may be referred pain (migrane headache) and patients may exhibit discomfort by decreased activity, increased sleeping or subtle changes in behavior.1 The signs of pain may not even be noted by the owner until the discomfort is treated, at which time the patient may be noted to return to normal activity or “act like themselves again.” Primary, or breed related, glaucoma in dogs is most commonly due to closure of the aqueous drainage angle or Primary Angle Closure Glaucoma (PACG).1 Females are approximately twice as likely to develop PACG compared to males.2 PACG has different features for different canine breeds, however, the end result is failure of normal aqueous outflow, causing significant intraocular pressure elevation. Acute primary glaucoma may often be treated medically or surgically if addressed immediately, even if there is vision loss at the time of increased intraocular pressure.1,3,4 Chronic primary glaucoma causes extensive intraocular damage and blindness. Therapy is aimed at preventing intraocular pressure spikes, decreasing intraocular pressure and maintaining functional vision.4-7 This therapeutic goal is rarely achieved long term with medication alone and surgical intervention is almost always necessary.5 To preserve functional vision, glaucoma surgery is usually recommended early in the disease course due to the aggressive nature of this disease. Typical surgeries performed include laser cyclophotocoagulation (ciliary body destruction) and anterior chamber valve placement.5 The combination of these surgeries resulted in good control of the intraocular pressure in 76% of cases.5 In cases of irreversibly blind globes, more permanent salvage procedures are recommended as glaucoma is painful (enucleation or an intrascleral prosthesis).

Secondary glaucoma results from other underlying ocular pathology. The most common causes are lens luxations (most often seen in Terrier breeds), uveitis and cataracts. Treatment is aimed at reducing the intraocular pressure and addressing the underlying cause of pressure elevation. Topical glaucoma therapy should be limited, in cases of secondary glaucoma, to medications that do not exacerbate pre-existing ocular disease. Topical carbonic anhydrase inhibitors (e.g. dorzolamide, brinzolamide) or topical beta blockers (e.g. timolol) are recommended for primary or secondary glaucoma. Prostaglandin analogs (e.g. latanoprost, travaprost), while often the first line of therapy for primary glaucoma, should be avoided for secondary glaucoma therapy as they may exacerbate pre-existing ocular disease.


         Image ( A )

         Image ( A )

                   Image ( B )

                   Image ( B )


A patient with acute glaucoma is depicted (A). Note the severe scleral injection and corneal edema. Acute glaucoma must be addressed immediately in order to preserve vision and treat patient discomfort. A patient with chronic glaucoma is depicted (B) Note the significant buphthalmos (globe enlargement), scleral injection and corneal edema. This eye is irreversibly blind, but is quite painful. Therapy is aimed at providing long term patient comfort. Prophylactic therapy should always be instituted in the contralateral eye if an eye is removed for intractable, primary glaucoma.


1. Reinstein S, et al. Canine glaucoma: pathophysiology and diagnosis. Compend Contin Educ Vet. 2009:10;450-2.

2. Tsai S, et al. Gender differences in iridocorneal angle morphology: a potential explanation for the female predisposition to primary angle closure glaucoma in dogs. Vet Ophthalmol. 2012:15S1;60-3.

3. Scott E, et al. Early histopathologic changes in the retina and optic nerve in canine primary angle-closure glaucoma. Vet Ophthalmol. 2013:16S1;79-86.

4. Dees D, et al. Efficacy of prophylactic antiglaucoma and anti-inflammatory medications in canine primary angle-closure glaucoma: a multicenter retrospective study (2004-2012). Vet Ophthalmol. 2013:5.

5. Sapienza J, et al. Combined transscleral diode laser cyclophotocoagulation and Ahmed gonioimplantation in dogs with primary glaucoma: 51 cases (1996-2004). Vet Ophthalmol. 2005:8:121-7.

6. Miller P, et al. The efficacy of topical prophylactic antiglaucoma therapy in primary closed angle glaucoma in dogs: a multicenter clinical trial. J Am Anim Hosp Assoc. 2000:36:431-8.

7. Willis A, et al. Advances in topical glaucoma therapy. Vet Ophthalmol. 2002:5;9-17.

Feline Herpesvirus: Ocular Manifestations

By: Rachel Mathes, DVM, MS, Diplomate ACVO

Feline herpesvirus-1 (FHV-1) is a common viral agent in cats, ubiquitous in the feline population.1It is estimated that 90-95% of cats harbor the virus, usually as a latent infection.  Most often this virus does not cause clinical disease in healthy cats; however, a certain percentage of cats develop recurrent or recrudescent disease.1,2Neonatal infections may cause serious ocular disease or blindness.  Most often, however, if an adult cat is affected, this disease causes ocular morbidity with varied severity.3Viremia appears to be important in the initial infection, but may be of less importance in recrudescent disease.4FHV-1 is directly epitheliotoxic to conjunctival and corneal epithelial cells.  Because of this, the most common ocular manifestations of FHV-1 disease are keratitis and conjunctivitis.5Feline herpesvirus is difficult to detect using serology, PCR and VI (virus isolation), therefore, the diagnosis is usually made based on clinical suspicion of disease.4Feline herpesvirus 1 cause changes to the preocular tear film with affected cats having an increased tear film break up time (increased drying on the ocular surface) and decreased goblet cell density.6Clinical signs may vary with herpetic disease, but blepharospasm (squinting), blepharedema (eyelid swelling), conjunctival hyperemia, chemosis (conjunctival edema), variable corneal ulceration, and corneal vascularization are commonly present (figure).1Secondary signs related to chronic irritation may also be noted and include corneal sequestrae, entropion, dry eye disease, corneal perforation and secondary bacterial infections. Treatment is aimed at supportive care including tear stimulants, tear replacers, reducing environmental and external stressors, and topical antibiotics if corneal ulcers are present.  Antiviral therapy is sometimes recommended in severe cases of FHV-1 infections.7Options for antiviral medications include topical and/or systemic therapy.8Oral lysine has not been shown to improve the clinical signs of herpetic disease.9In fact, lysine has caused worsening of clinical signs in some studies.10This disease may be frustrating to treat and treatment may extend weeks, months or years.  Because the virus is so common in feline populations, caution is advised in treating any cat exhibiting signs of keratitis or conjunctivitis with a topical or oral steroid as steroids have been shown to cause viral recrudescence. 

          Image  ( A )

          Image  ( A )

                        Image ( B )

                        Image ( B )

 The left (A) and right (B) eye of a patient with clinical signs of herpesvirus are depicted.  Eyelid swelling, conjunctival hyperemia and chemosis are present in both eyes.  This patient was also sneezing on examination, a sign consistent with active herpetic disease. Both eyes were painful, as manifested by the third eyelid elevation.  The right eye has extensive corneal vascularization and corneal ulceration present.  Cats presenting with active corneal and conjunctival disease should receive supportive therapy +/- antiviral medications.  Topical and oral steroids should always be avoided.



1. Gould D. Feline herpesvirus-1: ocular manifestations, diagnosis and treatment options.  J Feline Med Surg. 2011; 13: 333-46.

2. Zicola A, et al. Feline herpesvirus 1 and feline calicivirus infections in a heterogenous cat population of a rescue shelter. J Feline Med Surg. 2009;11;1023-7. 

3. Wieliczko A, et al. Feline herpesvirus 1 and Chlamydophila felis prevalence in cats with chronic conjunctivitis. Pol J Vet Sci. 2010;13:381-3.

4. Westermeyer H, et al. Assessment of viremia associated with experimental primary feline herpes

5. Hillstrom A, et al. Evaluation of cytologic findings in feline conjunctivitis. Vet Clin Pathol. 2012;41:283-90.

6. Lim C, et al. Effects of feline herpesvirus 1 on tear film breakup time, Schirmer tear test results and conjunctival goblet cell density in experimentally infected cats.  Am J Vet Res. 2009;70:394-403.

7. Fontenelle J, et al. Effect of topical ophthalmic application of cidofovir on experimentally induced primary ocular feline herpesvirus-1 infection in cats. Am J Vet Res. 2008;69:189-93.

8. Thomasy S, et al. Pharmacokinetics of famciclovir and penciclovir in tears following oral administration of famciclovir to cats: a pilot study. 2012;15:299-306.

9. Rees T, et al. Oral supplementation with L-lysine did not prevent upper respiratory infection in a shelter population of cats. J Feline Med Surg. 2008;10:510-3.

10. Drazenovich T, et al. Effects of dietary lysine supplementation on upper respiratory and ocular disease and detection of infectious organisms in cats within an animal shelter. Am J Vet Res. 2009:70:1391-400.

Cataracts and Cataract Surgery

By: Rachel Mathes, DVM, MS, Dipolmate ACVO

Facts about Cataracts

  • Inherited cataracts are the most common type in dogs
  • 50% of diabetic dogs get cataracts within 6 mos and 80% of diabetic dogs within 16 mos of diagnosis
  • Success rate of cataract surgery is 90-95%
  • Best surgical outcome is associated with immature cataracts prior to complete blindness

Cataracts, or opacities of the lens, occur commonly in dogs and are most often inherited. The second most leading cause of cataracts in dogs is canine diabetes mellitus. Feline cataracts are typically secondary to underlying systemic or ocular pathology and are much less common than canine cataracts. Cataracts may cause vision loss or progress to total blindness. In addition, cataracts may cause other ocular complications such as chronic uveitis, retinal detachments and glaucoma. Cataracts may be unpredictable and variable in their progression. The treatment for cataracts causing vision loss is small-incision cataract surgery performed by phacoemulsification and aspiration with placement of an artificial lens to achieve emmetropia (normal focusing power) (1,2). No medical therapy has been shown to treat cataracts.

Cataract surgery has dramatically improved in human and veterinary medicine in the last several decades with small-incisional (~3mm) surgery becoming the standard of care. Phacoemulsification or phacofragmentation of the lens with automated aspiration has replaced more archaic intracapsular lens extraction surgeries (1,3).  The success rate for cataract surgery is very high with overall estimates at 90-95% short term and 85-95% long term (1,4). Certain breeds such as Labradors, Cocker Spaniels and Boston Terriers have been identified as having a higher risk of complications after cataract surgery, however, the overall complication rate is still low (2,4). Complications after cataract surgery may include retinal detachments, glaucoma, uveitis, corneal ulceration and chronic intraocular inflammation with fibrovascular membrane formation. Hypermature cataracts have been associated with a higher postoperative incidence of glaucoma (4).  Immature cataracts have a lower incidence postoperatively of complications than mature and hypermature cataracts (1,3,4).  In addition, subjectively, the adjustment period to normal vision after surgery is shorter and smoother for patients that are not completely blind prior to cataract surgery.

The overall client satisfaction with cataract surgery is also very high, being around 85-90%. Dissatisfaction was associated with failure to have regularly scheduled rechecks performed with the cataract surgeon. Therefore, long term rechecks are emphasized for any client having cataract surgery performed in their pet. Cataract surgery has a high success rate and is a viable therapy for restoration of vision for patients with blinding cataracts.  

                           Image ( A )

                           Image ( A )

                            Image  ( B )

                            Image  ( B )

A patient with a blinding, mature cataract is depicted (A). Notice the iridal darkening from chronic uveitis and complete lens opacity. A patient one day after cataract surgery is shown (B). Note the translucent artificial lens and overall comfort. This patient’s vision was restored following cataract removal.


1. Miller TR, et al. Phacofragmentation and aspiration for cataract extraction in dogs: 56 cases (1980-1984). J Am Vet Med Assoc. 1987; 190: 1577-80.

2. Klein HE, et al. Postoperative comnplications and visual outcomes of phacoemulsification in 103 dogs (179 eyes): 2006-2008.

3. Sigle KJ, Nasisse MP. Long term complications after phacoemulsification for cataract removal in dogs: 172 eyes (1995-2002). J Am Vet Med Assoc. 2006; 228: 74-9.

4. Biros DJ, et al. Development of glaucoma after cataract surgery in dogs: 220 cases. J Am Vet Med Assoc. 2000; 216: 1780-6..

5. Appel SL, et al. Evaluation of client perceptions concerning outcome of cataract surgery in dogs. J Am Vet Med Assoc. 2006; 228: 870-5.

Salivary Mucocele

By: April Guille, DVM, Diplomate ACVS

A salivary mucocele, or a sialocele, is a collection of saliva in the subcutaneous tissues near the site of a leaking salivary duct or gland. The most common gland affected is the sublingual salivary gland, but any of the four major salivary glands can cause a sialocele. The location of the swelling often determines the presenting signs and indicates the involved salivary gland. The two most common locations of saliva collection are the ventral cervical area and under the tongue, although swelling can occur in the pharyngeal area, causing dyspnea, or under the ventral orbit, leading to exophthalmos. Animals with labored breathing due to a pharyngeal sialocele are in danger of airway obstruction and the swelling should be opened up for immediate drainage. Sialoceles can be caused by trauma, sialoliths, neoplasia, foreign bodies, or recent oral surgery, but often the cause is unknown. No sex predisposition has been found; dachshunds, poodles, Australian silky terriers, and German shepherds are predisposed.

On aspirate, the fluid is often viscous and clear or blood-tinged with small to moderate numbers of nondegenerate nucleated cells in a proteinanceous background. Conservative treatment by drainage alone is not recommended due to the high rate of recurrence. Definitive treatment involves removing the affected glands along with drainage; ranulas and pharyngeal sialoceles are treated with marsupialization. Although the sublingual gland and duct system are the most commonly affected, removal of the sublingual gland requires removal of the mandibular gland as well due to their common capsule and close association. The prognosis is excellent with complete removal of the gland, with a recurrence rate of less than 5 percent.

Facts about Sialoceles

Four main presentations include exophthalmos, labored breathing, dysphagia, or ventral cervical swelling

Sublingual salivary gland is the most commonly affected gland

Surgical removal of the affected gland is recommended to prevent recurrence

Excellent prognosis with surgery


Surgical Introduction

  Our state of-the-art surgery suite is equipped with modern anesthesia machines, heated surgery tables, and patient monitoring devices. Our surgeons specialize in soft tissue and orthopedic surgeries. Many Maine veterinarians refer more complicated procedures to our surgeons.
Many pet owners are unaware of specialization in veterinary medicine although they are quite familiar with it in human medicine. A specialist in veterinary medicine is quite similar to the human counterpart, both having gone through additional years of study and training to dedicate themselves to their chosen area. As the human physician will refer patients to a surgeon for complicated procedures, veterinary practitioners often refer surgical cases to a veterinary surgeon.

The American College of Veterinary Surgeons (ACVS) was formed to acknowledge and regulate the training and certification of veterinary surgeons. To achieve Diplomate status in the ACVS, a veterinarian must complete at least four years (one year of internship and three of a surgical residency) in a program accredited by the ACVS. Upon completion of the residency the candidate must submit credentials to the ACVS for review. The credentials document the individual’s training including all the surgeries they have performed, the Diplomate who supervised them, all class work done, lectures given, and scientific papers published. If these credentials are accepted, they are invited to sit for the certifying exam. This is a two day exam consisting of oral, written, and practical portions. Only upon successful completion of all three parts do they attain the status of Diplomate in the American College of Veterinary Surgeons. This is a rigorous and time consuming process that ensures that those achieving Diplomate status are fully qualified to perform any and all types of specialized surgery that your pet may require. Small animal surgery is typically divided into three areas: orthopedics, soft tissue, and neurosurgery.

Orthopedic surgery involves bones, joints, muscles, tendons, and ligaments. Fractured bones and torn ligaments are some of the most common injuries seen by the veterinary surgeon. In many cases, there are multiple injuries to the pet often as the result of trauma. Advanced techniques including the use of steel plates and screws or elaborate bone pin and clamp systems are required to adequately stabilize these injuries so that the pet can heal normally.

The surgeon also sees more subtle, chronic injuries that can be difficult to diagnose and frustrating to the pet owner. Sporting dogs, like human athletes, may acquire these injuries that though not debilitating, decrease their performance in the sport. Often, however, these sporting dogs are stoic and do not show their pain easily. A thorough orthopedic exam, radiographs (x-rays), and specialized procedures may be required to make the diagnosis in these complex cases.

Hip Dysplasia
Of course not all orthopedic problems are the result of injury. Many pets are born with conditions that eventually cause debilitating lameness. Hip dysplasia is a condition where the hip joint is malformed resulting in a looseness or laxity. This laxity leads to the development of arthritis. Hip dysplasia is a well recognized condition that is widespread in many breeds today. It can be heritable or passed on from generation to generation, but heredity is only part of the problem. Two parents with normal hips can produce a dysplastic puppy though the chance is less than if one or both parents has hip dysplasia. Do not ignore the signs of hip dysplasia just because you were assured that your puppy would not have it. The signs of hip dysplasia can include "a bunny hopping" gait (both rear legs move forward together), an obvious lameness, trouble getting up, and/or hesitancy to jump or go up and down stairs. The diagnosis of hip dysplasia is made with an orthopedic exam and radiographs (x-rays) of the hips. Young dogs should be examined by a veterinarian early as there are treatment options to prevent debilitating arthritis. (see advanced techniques)

Osteochondritis Dissecans (OCD)

Osteochondritis dissecans (OCD) is another congenital abnormality which can occur in any joint although it is most commonly seen in the shoulder, elbow, stifle (knee), and hock (ankle). Technically it is a failure of subchondral ossification which in general terms means the cartilage of the joint is not well attached and results in a loose flap of cartilage in the joint. It can cause significant lameness and arthritis. The treatment of choice is usually surgical removal of the loose piece via arthrotomy (opening the joint) and arthroscopy. The outcome depends on the joint or joints involved and the degree of arthritis already present. The diagnosis is made with radiographs (x-rays) and again early diagnosis is beneficial.

The elbow joint has several conditions besides OCD which can occur in the young dog. These include fragmented coronoid process (FCP), ununited anconeal process (UAP), and malalignment of the joint surface. The first two, FCP and UAP, are similar to OCD in that there is a loose fragment (in these cases bone as well as cartilage) that causes lameness. The third condition, malalignment, is where the joint surfaces of the three bones that meet at the elbow (the humerus, the radius, and the ulna) do not fit together. This may be because either the radius or the ulna is growing too fast for the other bone to "catch up". All of these conditions can result in debilitating arthritis. They are diagnosed by radiographs and surgery can be performed to correct the problem or alleviate the pain if diagnosed early in the disease process.

Other growth deformities are seen in pets as a result of birth defects or trauma to the young animal. Corrective surgery should be performed to give the pet normal or near normal use of the limb.

Soft tissue surgery is a very broad category involving head and neck surgery, cardiovascular (heart), pulmonary (lung), gastrointestinal (stomach, intestine, liver, pancreas), and urogenital (kidneys and bladder). The conditions in each category may be either congenital (from birth) or acquired. Acquired disorders are those not related to hereditary or birth defects, and include trauma, infection and cancer.

Patent Ductus Arterious (PDA)
Some diseases cats and dogs are born with that require surgery include heart and blood vessel problems such as patent ductus arteriosus (PDA) and persistent right aortic arch (PRAA). A PDA is a blood vessel that is present in the fetus that should close down at or shortly after birth. If it stays open, blood is shunted from one side of the heart to the other overloading the system. The puppy or kitten will have a heart murmur that can be detected on physical exam. They often act quieter that normal and tire easily. The diagnosis is made by detecting the murmur, radiographs of the chest, and/or ultrasound exam of the heart. Surgery can completely correct this condition. A thoracotomy (incision into the chest cavity) is performed and the abnormal vessel is closed off with suture material.

Persistent Right Aortic Arch
A persistent right aortic arch (PRAA) is the abnormal development of blood vessels which results in a tight band constricting the esophagus. The esophagus is the tube which brings food from the mouth to the stomach. When the puppy or kitten starts eating solid food, they will be unable to hold it down for much of the time. The diagnosis is made by introducing special dye into the esophagus and taking radiographs (x-rays). To correct this, a thoracotomy is performed and the tight band of tissue is removed, alleviating the obstruction. It is important to do this surgery as early as possible to prevent permanent damage to the esophagus.

Ectopic Ureters
Another congenital defect involves the urinary system and is called ectopic ureters. The ureter is a tube that brings urine from the kidney to the bladder. In the ectopic ureter condition this tube does not empty into the bladder but instead goes further out to the urethra or vagina. Pets with this condition are often incontinent (leak urine), have urine scald around their genitalia, and develop urinary tract infections. This condition is also diagnosed with a special dye that identifies the abnormal ureter. Abdominal surgery is performed and the abnormal ureter is attached to its normal position in the bladder. Once again, early diagnosis is beneficial.

Surgery on pediatric animals requires specialized equipment, supplies, and expertise. Heated surgery tables help patients maintain body temperature, certain intravenous fluids are given to stabilize blood sugar, anesthetic drugs are carefully selected, and careful and complete monitoring of anesthesia are performed to ensure a complete and speedy anesthetic and surgical recovery. Once the young patient is awake from surgery recovery is remarkable. Even chest surgery patients are eating within one hour and dozing comfortably. They are often running and playing within a week of surgery and would be even sooner if they were allowed!



Acquired soft tissue diseases or conditions are many and varied. Pets may ingest inanimate objects that require surgery to remove or they may suffer trauma requiring surgery such as a ruptured spleen or bladder from being hit by a car. Pets can get diseases like humans such as gallstones, kidney or bladder stones, and stomach ulcers. Like their human owners with these conditions, surgery is sometimes necessary.

A large part of soft tissue surgery is now oncological (cancer) surgery. Cancer can and does occur in any part of the body and can be either benign or malignant. The best test to determine the type and nature (benign or malignant) of a tumor is a biopsy where a portion or all of the tumor is removed and sent to a pathologist for microscopic classification.

Benign tumors may need to be removed if they are interfering with the other neighboring body structures, enlarging dramatically, causing discomfort, or are unsightly. If completely removed, the benign tumor should not recur or spread to other body areas. One example of a benign tumor is a lipoma or fatty tumor that occurs anywhere, but is often seen and felt under the skin in older pets. A simple aspirate using a small needle to obtain a sample is usually adequate for diagnosis. Surgical removal results in a skin incision that heals rapidly and causes minimal discomfort for the pet.

Malignant tumors often require a more aggressive approach and additional therapy beyond surgery, including chemotherapy or radiation. Surgery, however, is the main stay of many cancer therapies and is often the only hope for a complete cure.

Malignant tumors can be deceivingly small in appearance and what can be seen may only be the "tip of the iceberg". It is therefore very important to be aggressive with surgery making a wide surgical excision in an attempt to get rid of all of the cancer. This may involve removing a portion of the chest wall and ribs in cases of tumors of the thorax (chest); removing half of the lower or upper jaw in the case of oral (mouth) tumors; or amputating the limb in cases of bony tumors of the limb. These may sound drastic but are often essential for cure. The biggest mistake in oncological surgery is to perform inadequate resection allowing the cancer to recur. It may be more difficult or impossible to completely remove at a second surgery, the cancer may have spread to other areas in that time interval, and it means a second surgery for the pet. The first chance is the best chance for cure. Even aggressive (radical) surgery in most pets is very well tolerated and can be very cosmetic. Early intervention is the key to success!


Pain Management
Whenever surgery is performed, there is some postoperative pain. The amount and duration varies with the type of surgery and the condition of the patient. Although we cannot ask the pets how they feel, we can and should assume it is similar to humans. A spay is probably less painful than amputation but both surgeries require addressing pain management (analgesia).


Pain control starts before surgery is performed. We now know that medicating prior to the onset of pain results in better pain control with less total drug required. This is called pre-emptive analgesia. All of our surgical patients receive a premedication drug, the type and amount depending on the level of expected discomfort. After surgery additional pain medication is often required. This may be injectable and given intermittently or on a slow intravenous dose. Oral medications for pain is often prescribed for the first few days to weeks at home.

An important part of patient comfort is TLC postoperatively. Providing warmed blankets and heating pads, a clean and dry bed, and a good scratch behind the ears, go a long way toward lessening their discomfort and anxiety.

Triple Pelvic Osteotomy (TPO)
Hip dysplasia is a condition where the femoral head and acetabulum (the ball and cup) of the hip joint do not fit well together. The cup or acetabulum is too shallow and the femoral head or ball slips partially in and out as the dog walks. This laxity or looseness of the hips can lead to debilitating pain and arthritis.

The triple pelvic osteotomy (TPO) is an orthopedic surgery performed to lesson or eliminate the pain and arthritis in dogs with dysplasia. As the name implies three cuts are made in the bone of the pelvis and the bone is rotated usually 20 to 40 degrees so that the cup of the hip joint can cover or capture the ball of the femur such that it can not slip in and out. The cut pelvis is held in place at this angle with a steel plate and screws while the bone heals, usually in three to six weeks.

Hip dysplasia usually involves both hips although one leg may seem worse than the other. A triple pelvic osteotomy ideally is performed on both hips. The operations are staged three weeks apart to let the first side heal. Occasionally, but rarely, they are done at the same time. Not infrequently as few as 7 to 10 days may pass until the second hip is operated on if the surgeon is concerned that arthritis might develop if the second operation is delayed. If arthritis is already present at the time of diagnosis this surgery is not indicated as it is meant as prophylactic surgery to prevent the development of arthritis.

Complications are very rare but have been reported to include implant failure (the plate pulls off or screws), infection, nerve injury, and trouble urinating. These complications are usually temporary or correctable.

Recovery from the TPO is rapid. The dogs are often bearing weight on the leg by the day after surgery and continue to improve over a few weeks. They are restricted to leash walks for 3 weeks at which time radiographs (x-rays) may be made to document healing. When healing of the bone is documented, normal activity is resumed and the dog usually requires no further therapy for pain management and lives a happy pain-free life.

Arthritis FHO/THR
Surgery is not always performed early enough to prevent arthritis and sometimes arthritis is inevitable either from one of the aforementioned conditions or simply the result of age. However it develops arthritis can be debilitating if left untreated. Newer medicines are available that have a higher potency and lower incidence of side effects to make arthritic pets comfortable. Weight control and an exercise program are key elements to successful arthritis management. If medical management fails there are surgical options that vary depending on the joint involved.

For hip arthritis there is the total hip replacement (THR) surgery or a femoral head and neck ostectomy (FHO). The THR is similar to that performed on people where the whole joint is replaced with metal and plastic components. It has a high success rate and low incidence of complications. Even though both hips often have arthritis it may be unnecessary to perform hip replacement on both hips. Complications could include infection, implant failure, and implant loosening. If they occur the implants may have to be replaced or completely removed. Fortunately this happens only rarely. The femoral head ostectomy (FHO) involves the removal of the ball of the hip joint and eventual formation of a "false" or fibrous joint. Pain is eliminated by removing the bone on bone contact that occurs in the arthritic joint. Often both hips must have surgery to make the pet comfortable. Both THR and FHO are considered salvage operations in that the normal joint is replaced or removed. While this most often tremendously improves the quality of life of the pet it would be best to prevent its development. A triple pelvic osteotomy (TPO) done early in a pet’s life can often prevent debilitating arthritis and pain from developing (see advanced techniques)

Arthritis in other joints may also require salvage surgery if medical therapy fails. Arthrodesis of a joint is a surgery where the cartilage is removed and the bones are held together with metal plates or pins until they fuse. This eliminates the motion in that joint but takes all arthritis pain away. Arthrodesis has been successfully performed in the shoulder, elbow, carpus (wrist), stifle (knee), hock (ankle), and toes.

Cancer Surgery
Many people balk when first discussing aggressive options for malignant cancer. They are concerned about their pet’s quality of life postoperatively and any deformity that may result. Osteosarcoma is cancer of bone that often requires amputation for the best outcome. Amputation of the limb is well tolerated by both dogs and cats. They rapidly adjust to bearing weight on the other three limbs and in a few short days are more comfortable than they were before surgery. Bone cancer pain in people is excruciating and we must assume it is the same for animals. They don’t understand their pain and often sleep and eat less because of it. Simply removing this source of pain can dramatically increase their outlook and quality of life.

Osteosarcoma can occur in the ribs as well, requiring removal. Chest wall surgery is less obviously deforming than amputation because the surgeon can remove up to 5 ribs and replace the area with a plastic mesh which is covered by skin as the incision is closed. When the hair coat grows back, the defect is often not apparent. Recovery from surgery is again quite rapid and full activity for the pet is resumed in two to four weeks.

Oral tumors (in the mouth) are common cancers requiring surgery. The tumor types include squamous cell carcinoma (SCC), fibrosarcoma (FSA), and melanoma. SCC and FSA can be cured with surgery alone if diagnosis is early enough and surgery is aggressive enough. Melanomas are aggressive tumors that have often spread by the time of diagnosis but palliative surgery can be performed. Palliative surgery is when surgery does not cure the animal or increase their life span, but does improve their quality of life. The surgery involves removal of the portion of affected bone with a "safety zone" of normal tissue removed as well to ensure complete removal of the cancer. Almost the entire lower jaw or three quarters of the upper jaw can be removed although most tumors require far less, usually involving one quarter of either upper or lower jaw. There often is some cosmetic defect but when the hair grows back it is often minimal. This is especially true in dogs whose pendulous lip is often able to cover large defects. The surgical recovery is again quite amazing as pets are usually eating the next day.

Other examples of cancer surgery include chest surgery to remove lung cancer and abdominal surgery for liver, spleen, and intestinal cancer. These leave no deformity other than a small scar and the patient generally recovers rapidly.



The word "endoscopy" denotes the use of fiberoptic instruments to investigate and possibly biopsy certain body cavities. It is a "noninvasive" procedure which means no surgical incisions are required. For the patient, this means a short anesthetic period with a rapid recovery. All endoscopies in small animals require full anesthesia, and therefore may require pre-anesthetic evaluations such as blood tests, radiographs (xrays), and/or ultrasound.  Endoscopies are usually considered among the low-risk procedures in veterinary medicine. 

All pets admitted for these procedures are first evaluated by a veterinarian who will examine your pet, the medical history, the feasibility of endoscopy, and carefully determine any ancillary tests that will be required. At that time, a written estimate can be given, and questions or concerns you may have can be discussed in detail. Pets are generally required to be admitted to the hospital for the day. Please fast your pet (no food; water OK) for at least 12 hours prior to the admission time.

Canine Cystoscopy

Cystoscopy is rigid endoscopic evaluation of a female dog’s vagina, urethra and bladder, and the male dog's urethra and bladder.  Cystoscopy is specific and sensitive for the diagnosis of urinary tract problems and it provides additional information not obtained through radiographs, contrast studies or ultrasound. Indications for cystoscopy are: blood in the urine (hematuria), bladder/ urethral cancer, incontinence (leaking urine), recurrent urinary tract infections, small bladder stone removal, and vaginal discharge. Cystoscopy can be completed on all sizes of female dogs, and medium to large male dogs.


Bronchoscopy is fiberoptic examination of the respiratory system. This includes the larynx (voice box), trachea (windpipe), and bronchial tree. This is a short, day procedure that allows the internist to take samples and bacterial cultures of the airways. It may be preceded by chest radiographs (xrays), and certain blood tests. Common reasons for bronchoscopy are chronic cough, suspected pneumonia, allergy, or cancer.


Gastroscopy allows the internist to closely examine an animal 's esophagus, stomach, and the first portion of the small intestine. The health of these tissues can be assessed, biopsies harvested, and sometimes foreign objects can be retrieved. The pet is fasted at least 12 hours prior to the procedure, and is usually released on the same day. Common reasons for gastroscopy are weight loss, vomiting, diarrhea, and anorexia.


Colonoscopy allows the doctor to evaluate disease processes of the large intestine (colon), and rectum. This process is recommended for animals that have chronic diarrhea, are straining to defecate, and/or have blood in their stools. This procedure sometimes requires a 24 hour fast (water is okay).


 Rhinoscopy is the use of fiberoptics to investigate the nasal cavity. It can be used for dogs and cats and is a short day procedure. It is usually accompanied by skull and nasal radiographs, and biopsy. Chronic sneezing, snorting, "reverse sneezing," chronic nasal discharge, or nasal bleeding would be indications for rhinoscopy.

Feline Heart Disease

Heart disease in domestic cats is actually quite common, which may come as a surprise to feline owners. It can strike any age or any breed of cat. One of the most challenging aspects of feline heart disease is that cats may not show any warning signs (such as exercise intolerance, coughing, weakness)until the process is very advanced. This means that a cat can literally be playing vigorously one day, and suddenly have trouble breathing. Untreated heart disease often progresses to heart failure, blood clot formation, and death.

The detection of a new heart murmur by your veterinarian (often on routine examination) can be the first sign that changes in the heart have taken place. While not every murmur signals the onset of heart disease, a further investigation is warranted since those murmurs which are a result of heart disease cannot be distinguished from "innocent" murmurs by routine tests alone.

Fortunately, advances in companion animal medicine enable veterinarians to efficiently diagnose cardiovascular disease in cats, even in its early stages. In many instances, if heart disease is detected prior to the stage of actual heart failure, it can be successfully controlled with medication(s). A feline with carefully controlled heart disease may live symptom-free for years!


The first test for heart disease begins with a thorough physical examination. During the exam, the veterinarian will determine your cat's heart rate and rhythm. A persistently elevated rate, or a rhythm that is irregular can be associated with heart disease in cats. The presence of a murmur (especially one not previously detected) may be further evidence of heart disease. In advanced cases of heart disease, abnormal sounds in the lungs may be heard. A weak or irregular pulse can also occur. The results of the physical exam may lead to further testing.

Chest Radiographs (x-rays)

Chest radiographs are important components in the diagnosis of feline heart disease. A diseased heart will most often enlarge over time. In advanced stages, fluid may be detectable in the chest cavity (pleural effusion) or in the lungs themselves (pulmonary edema).

Electrocardiogram (EKG or ECG)

An electrocardiogram (EKG or ECG) is a tracing of the electrical activity of the heart. It documents heart rate and rhythm. In addition, subtle changes can occur in the shape of the ECG spikes that can reveal certain types of pathological changes in the heart. It is a rapid and painless test that can be performed in the veterinary office.


An echocardiogram, also known as a cardiac ultrasound exam, is one of the most advanced and sensitive tests for determining the presence of heart disease in animals. It is painless and generally does not require sedation. The technique uses sound waves to actually visualize the heart in action. From this exam, the dimensions of each heart chamber can be determined.

Ultrasound can also detect the presence or absence of fluid in the sac around the heart (pericardial effusion), fluid in the chest, congenital heart defects, abnormalities of the heart valves, blood clots within the heart itself, or heart tumors (rare in cats). Most importantly, the echocardiogram can actually determine the type and degree of heart dysfunction. An accurate assessment of heart disease is paramount to effective treatment.


Dilative cardiomyopathy

Dilative cardiomyopathy denotes heart disease that results in an enlarged heart with thinning and weakening of its muscular walls. The weakened heart cannot pump efficiently which subsequently can lead to fluid accumulation in the lungs and/or chest cavity (analogous to congestive heart failure in humans). Enlargement of the heart can lead to leakage at the heart valves, creating a murmur.

This form, although more difficult to successfully control, has become less common in recent years. A few years ago, research showed that deficiency of the amino acid taurine in the feline diet was one of the main causes of dilative cardiomyopathy. Since that time, most commercially made feline diets are supplemented with taurine.

Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is the most commonly diagnosed heart disease in cats. The walls of the heart become much thicker and stiffer than normal. This results in a smaller chamber to hold the blood, and diminishes the amount of blood pumped out with each beat. Consequently, the heart has to accelerate and use more energy to accomplish its original task. The geometric changes in the heart can lead to leakage at the valves, and development of a murmur. As the disease progresses, the heart can become so thickened that it cannot pump the blood forward at an adequate rate. This usually results in fluid accumulation in the lungs.

The cause in most cases is unknown, but genetics are thought to play a role in at least some cat breeds. While it is most common in middle-aged male cats, it can be seen in either sex as early as 6 months of age. Hypertrophic cardiomyopathy remains the most treatable form of feline heart disease.

Restrictive cardiomyopathy

Restrictive cardiomyopathy is a less common, less defined type of heart disease in cats. It is more difficult to detect, as many cats will have near normal echocardiograms, but their heart walls seems "stiffer" and less efficient at pumping blood forward. It is thought that in such cats the heart wall muscle cells become slowly replaced with less functional scar tissue. Cats with this type of disease may shows signs consistent with either dilative cardiomyopathy, hypertrophic cardiomyopathy, or both.


Therapy for feline heart disease depends on which type is diagnosed and how advanced the disease is. As previously mentioned, cats with hypertrophic cardiomyopathy have the best long term outlook The most serious consequences of progressive heart disease are weight loss, anorexia, difficulty breathing, weakness, and blood clot formation (with possible limb paralysis). Cats with advanced heart disease are at risk for sudden death.

Early detection and intervention, however, can be very rewarding for many cats and their owners.


Furosemide (Lasix‰) is a diuretic ("water pill") used in all types of feline heart disease. It reduces the volume of fluid that the heart has to pump, and removes fluid from the lungs. This makes the heart's work easier.


Enalapril (Vasotec¨ or Enacard‰) is a drug known as a vasodilator. It is very useful in many types of heart disease. It lowers blood pressure and reduces the workload of the heart. In dilating the vessels downstream from the heart, it lowers the resistance to blood being pumped forward.


Diltiazem (Cardizem‰) is a drug used in humans and animals. It is a "calcium channel blocker." Most commonly used for hypertrophic cardiomyopathy, it reduces the stiffness and work of heart walls. It has been documented to prevent or reverse wall thickening in many cats, and is very well tolerated.


Digitalis (Digoxin® or Lanoxin®) is a very old but useful drug utilized in people and animals mainly for treatment of dilative cardiomyopathy. It strengthens the contraction of the heart muscle with the goal of improving pumping function. It also can correct certain types of irregular heart rhythms. Because it has a narrow safety range, the drug concentrations in the patient's bloodstream must be monitored periodically.


Betablockers such as propranolol (Inderal®) or atenolol (Tenormin®) are prescribed mainly for hypertrophic cardiomyopathy. These drugs slow the rhythm of the heart, allowing the attenuated chambers to fully fill with blood between heartbeats. This increases cardiac output and thus reduces the actual work of the heart. Betablockers also lower blood pressure and regulate heart rhythms.


One of the health risks for feline heart disease patients is the formation f a blood clot in the heart. The clots can form in the enlarged heart chambers where the blood undergoes increased turbulence. If a piece of the clot leaves the left side of the heart and travels downstream, it often lodges in the large blood vessel known as the aorta. Since the aorta is the trunk artery carrying blood to the back half of the body, loss of this blood flow can cause temporary or permanent paralysis. The best prevention of this complication is to 1) adequately control the heart disease and reduce heart chamber size and 2) low dose aspirin therapy. While cats can have toxic or lethal reactions to high dose aspirin or any dose of acetaminophen (Tylenol®), low dose aspirin can often be used safely. The usual dose is 1/4 of an adult regular aspirin or 1 baby aspirin (81 mg.) per cat TWICE WEEKLY.