We noticed some time back that Tropicana seemed friskier than ever despite her 15 years. She had also lost a fair bit of weight, without any loss of appetite, but that seemed like an improvement — she had always been overweight. But when she seemed to be vomiting too frequently we decided to take her to the vet who, after a blood test, diagnosed her with Hyperthyroidism.
We might enjoy a friskier, skinnier Tropicana, but the condition is quite dangerous, leading quickly to heart disease and other serious conditions. The immediate treatment is multiple daily doses of Methimazole, from which we have learned that she really does not like to take pills.
Unless we want her to keep taking these pills the rest of her life (the pills have a high incidence of side effects) we have two treatment options. The first is a partial or total Thyroidectomy, which has a high rate of complications and is contraindicated for older animals and may require subsequent lifetime dosing of thyroid hormone pills.
The other alternative, and an attractive one, is a single dose of Iodine-131 which is calibrated to kill the overproducing portion of the thyroid. Quite a simple procedure, but it has some consequences. Basically, the patient becomes too radioactive for the NRC to permit us to take her home in less than a week (the half-life of I-131 is 8 days). Tropi isn't going to like being away from home, and in isolation to boot.
Also interesting is the fact that for two weeks after she comes home, we'll have to treat the contents of her litterbox as radioactive waste. Hard to believe, but at least one cat owner was fined for improper disposal in these circumstances.
There are quite a few clinics that perform this procedure; we may take Tropi to Radiocat in San Mateo next month.