Thyroid Awry Q: My 18-year-old cat has been losing weight, even though she's been eating more. Her vet has diagnosed an overactive thyroid and recommended surgery. Is there any other way to help her?--C.O. A: The thyroid gland produces a hormone that, among other functions, regulates the rate at which the body produces energy. Elderly cats tend to develop tumors in the thyroid that produce the hormone in excess, which results in the body's burning itself out. Symptoms include weight loss, vomiting, diarrhea, excessive thirst and urination, and liver and heart failure. Medication can help prevent the tumor from producing the hormone, and there are pills to stabilize the heart rate. Since prolonged use of these medications can be fatal, surgery to remove the offending gland is recommended once everything is under control. A complete workup should be performed before surgery to make sure that the kidneys are working adequately. If they're not, the pills can be continued with frequent blood tests to regulate the dosage. An annual blood test in middle-aged and elderly cats may detect this disease early.