The options for treating feline hyperthyroidism - Veterinary Medicine
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The options for treating feline hyperthyroidism
You have numerous choices for treating hyperthyroid cats. Which therapy you choose depends on such factors as the cat's health, the expense the owner is willing to bear, your experience, and the proximity of a radioiodine facility.


The clinical importance of these studies seems to be that hyperthyroidism induces an artificial state of increased GFR, resulting in a decrease in serum BUN and creatinine concentrations. Treating hyperthyroidism (whether with surgery, methimazole, or radioiodine) reduces the GFR and causes an unmasking or progression of underlying chronic renal disease. Except for measuring GFR before treatment, no reliable clinical sign or laboratory test helps practitioners predict which cat might exhibit a clinically important deterioration in renal function after therapy. It is important to emphasize that the number of cats with severe or clinically relevant declines in renal function posttreatment is small. However, based on these studies, it is prudent to initiate low-dose methimazole therapy (or other forms of medical therapy) with renal and thyroid function monitoring after seven to 10 days before performing surgery or radioiodine therapy.


The method chosen to treat a hyperthyroid cat depends on several factors, including cost, convenience, and the patient's current health. Since hyper th y roidism can mask other illnesses such as renal disease, practitioners should conduct follow-up evaluations with physical examinations and laboratory testing to monitor thyroid hormone concentrations and kidney function over time. Cardiovascular parameters should also be examined periodically, especially if hypertension or heart enlargement were noted at the time of diagnosis. The frequency of checkups will depend on the treatment method chosen and the patient's response to therapy.

David S. Bruyette, DVM, DACVIM
VCA West Los Angeles Animal Hospital
1818 S. Sepulveda Blvd.
West Los Angeles, CA 90025


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