Radioactive Iodine
This is the treatment of choice if available and affordable. Ideally, only abnormal tissue will be destroyed and normal tissue should be spared. It’s equally effective if abnormal tissue is not located in the thyroid gland. Can also be used with adenocarcinomas (higher dose required). Cats do have to be relatively stable clinically to be treated and need to eat in clinic if treatment is to occur. Most cats are euthyroid within one or two months of treatment.
Percutaneous Ethanol Injection
This treatment has a learning curve, so an experienced operator is needed. Only one thyroid gland should be treated at a given time even if both thyroid glands are enlarged; the contralateral gland should be treated at a later date. The results with treatment of cats with unilateral involvement has been good, while hyperthyroidism has uniformly reoccurred in those with bilateral disease. Laryngeal paralysis is a common complication, which may be permanent or transient; bilateral laryngeal paralysis may be fatal. Horner’s also can occur.
Surgical Thyroidectomy
This is an effective, permanent treatment for hyperthyroidism with bilateral thyroidectomy being recommended given that 70 percent of cases have bilateral disease. Surgical removal can be staged if needed. Hypoparathyroidism can occur. Because of this, calcium concentration should be monitored daily for three days after the procedure. Levothyroxine supplementation (0.1 mg QD) is recommended for two months after bilateral thyroidectomy. Laryngeal paralysis and Horner’s syndrome occur rarely due to intraoperative trauma. <HOME>
