Conference Proceedings, (1996). International Veterinary Emergency and Critial Care Symposium, San Antonio, TX: p.141-145
Feline hyperthyroidism results from excessive circulating levels of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Hyperthyroidism, the most frequently occurring endocrine disorder of the cat, is most commonly a result of a functional thyroid adenoma and/or adenomatous hyperplasia. Both thyroid lobes are involved in the majority of cases. Thyroid carcinoma is a rare cause of hyperthyroidism in the eat. The cause of the adenoma is unknown. The disease affects middle-age to older cats; most cats are nine years old or older (range 5·22 years).