The Internal Medicine Department is well-equipped with high-resolution flexible video endoscopes and rigid video scopes that can be utilized for esophagoscopy, gastroduodenoscopy, pharyngoscopy, laparoscopy, cystoscopy, urethroscopy, vaginoscopy, and rhinoscopy. State-of-the-art high-resolution ultrasound machines are routinely used to perform abdominal and cardiac imaging, along with non-invasive biopsy and aspiration procedures. Digital video fluoroscopy systems enable procedures such as gastrointestinal/esophageal motility evaluation, evaluation for tracheal and bronchial disease, and interventional procedures such as tracheal and urethral stent placement performed with our radiology team.
GCVS is proud to offer the following interventional services:
In order to treat a hyperthyroid cat with radioactive iodine, a confirmed diagnosis of hyperthyroidism must be made prior to administration of radioiodine. Typical clinical signs include weight loss, abnormal and inappropriate vocalizing, increased appetite (although a small percentage of cats with hyperthyroidism will have decreased or no appetite), intermittent vomiting and / or diarrhea, possible increased water consumption and an overall restless or “cranky” demeanor. Although many cats will show some or all of these “typical” clinical signs of hyperthyroidism, many cats show only a few or no signs at all (“occult hyperthyroidism”). Upon presentation to your veterinarian, the diagnosis of hyperthyroidism is made by a blood test – either an elevated Total T4 or free T4 (fT4) value. However, these blood tests are not 100 percent accurate and a significant number (approximately 15 percent) of confirmed hyperthyroid cats will have a normal T4 and/or fT4. Just because a cat has a high T4 on a single blood test does not confirm hyperthyroidism. We have avoided unnecessary radioiodine treatment on many cats that have had “laboratory error” – in other words, these cats have an elevated T4 or fT4 and have been proven to not be hyperthyroid (negative diagnostic nuclear thyroid scan).
The “gold standard” and accepted way to confirm hyperthyroidism is with a diagnostic thyroid scan. Although, there are other less accurate and more expensive methods (T3 suppression test), the thyroid scan is a quick and 100 percent accurate way to confirm or deny feline hyperthyroidism. The thyroid scan is also a good predictor as to whether the hyperfunctional thyroid gland is aggressive in its appearance, which is suggestive of a thyroid adenocarcinoma (malignant thyroid cancer). Patients with thyroid adenocarcinoma typically have a poor prognosis as this cancer is very aggressive and tends to metastasize quickly. In fact, it is standard protocol in all veterinary schools and universities in the United States that all cats undergo a diagnostic thyroid scan prior to the administration of radioiodine in order to confirm the patient is truly hyperthyroid, and to confirm that the gland does not appear to be aggressive. Clinics that have chosen not to administer a thyroid scan all cats prior to radioiodine administration do so because lack the gamma camera (equipment necessary to perform a thyroid scan) and thus fall short of the “standard of care” we feel each patient is entitled to.
Pre-treatment with methimazole (Tapazole) is recommended for cats showing signs of renal disease (elevated creatinine, lack of ability to concentrate urine, etc.) in order to see if the subsequent lowering of the circulating thyroxin will cause the renal disease to worsen. If the cat’s thyroid levels lower into the normal range, while at the same time, the renal enzymes do not elevate, he/she may be a good candidate for radioiodine therapy. If the patient cannot tolerate the potentially serious side effects of methimazole (Tapazole), the only viable option may be a low dose of radioiodine therapy.
In all cases, methimazole (Tapazole) should be discontinued two weeks prior to the administration of radioiodine.
Radioactive licenses vary from one institution to the next, and as such, the isolation period in which these patients must be hospitalized may vary as well. In our case, most cats are hospitalized for 5-7 days. During this time, they are closely monitored and then released as soon as legally possible. While undergoing treatment, your pet will be tended to regularly by authorized, properly trained personnel. Unfortunately, the state prohibits owner visitation during this short period of time.
It is not against state regulations to administer needed medications during this period of time (antibiotics, insulin, etc.); however, only properly trained, authorized personnel can administer the medication.
Personal items (beds, baskets, toys, t-shirts) are permitted; however, they are closely monitored for any evidence of contamination with radioiodine. Unfortunately, if an item happens to become contaminated, we are unable to return it to you when your cat is discharged. At the time of discharge from our hospital, you will receive special at-home, post-op case instructions. Isolation is not necessary.
If the owner or an immediate family member of a hyperthyroid cat is pregnant or may be pregnant, or if persons under 18 years of age live in the house, you should inform the doctor of this during your initial appointment. In these cases, we keep the cat for an additional period of time to allow the radiation levels to drop even more than required by law to assure the safety of all individuals.
Our GCVS radiologists have extensive experience with radioactive iodine therapy. Throughout the last 15 years, we have successfully treated more than 3,000 cats with hyperthyroidism. Our doctors and staff understand the concern that an extended hospital stay can cause our patients and their families. For this reason, we strive to maintain the highest level of medical care in a relaxed and comfortable environment.
Please Note: In the unlikely event that a patient passes while undergoing radioiodine therapy, GCVS must hold the patient's remains for 90 days to allow their radiation levels to decrease to a safe-enough level before being released.