WHAT IS HYPERTHYROIDISM?
Hyperthyroidism is the most common endocrine disorder in cats. It occurs when a tumor is present on the thyroid gland (in the neck) causing it to produce excess amounts of thyroxine (T4) and triiodothyronine (T3) which can be devestating to the cat's health.
WHAT ARE THE SYMPTOMS?
The elevated T4 levels cause extreme weight loss, hyperactivity, and increased appetite, thirst, and urination. Vomiting, diarrhea, and heart problems including heart failure are also common,
HOW IS IT DIAGNOSED?
Feline Hyperthyroidism is diagnosed with a simple blood test that measures the T4 levels in the blood. Normal T4 levels are generally between 1 and 4. (Spot's was 16!)
WHAT ARE THE TREATMENT OPTIONS?
Hyperthyroidism can be treated 3 ways.
>Medication
>Surgery
>Radioactive Iodine injection
MEDICATION is in the form of Methimazole and is commonly given in 5mg tablets twice a day. This treats the symtoms of hyperthyroidism but not the cause. The tumor will continue to grow but the T4 levels are controlled. Medication is expensive: $30 to $60 USD each month and pills must be given orally twice a day to be effective. Pilling a cat is stressful, uncomfortable, and sometimes difficult and the pills, though effective, must be given for the rest of the cat's life. Going out to town is impossible unless Kitty comes with you or you have a very dedicated friend or family member willing to take over your cat pilling duties while you are gone.
SURGERY is not only highly invasive and expensive (usually more than $1,000 USD) but the results depend greatly on your veterinarian's skills as a surgeon. Thyroid surgery is difficult, at best. Remove too much and the cat can suffer from hypothyroidism (T4 levels that are too low) or hypocalcimia (deminished calcium production). Remove too little and the tumor can grow back making the surgery pointless. Additionally, there are the usual risks of surgery and annesthesia including death.
RADIOACTIVE IODINE (I-131) THERAPY is the treatment of choice. The radioiodine is given in a single injection and absorbed by the tumor killing it but leaving all healthy tissue unharmed. The cat must remain "hospitalized" for 3 to 10 days after the injection until it's radiation levels return to normal. After this one injection, thyroid levels should return to normal and no further medication or treatment is needed! The cost of this option is the only downfall: Approximately $1,200 USD.