Description    Hyperthyroidism, the most-frequently-diagnosed feline endocrinopathy, is usually caused by an adenoma or adenomatous hyperplasia and less often by adenocarcinoma. Enlarged thyroids might be palpated close to the trachea anywhere from caudal to the larynx to the thoracic inlet; in about 3/4 of cases both thyroid lobes are enlarged. Hypertrophic cardiomyopathy that can lead to heart failure can accompany hyperthyroidism. Large Thyroid Cysts in hyperthyroid or euthyroid cats with benign or malignant thyroid tumors can cause problems by mechanical obstruction.
Species   Feline
Signs   Abnormal behavior, aggression, changing habits, Abnormal lung or pleural sounds, Abnormal upper airway breathing sounds, Alopecia, Anorexia, Arrhythmia, Ataxia, Atrial tachycardia, Atrial, supraventricular, premature beat, Blindness, Bundle branch block, Change in voice, Congestion oral mucous membranes, Constant or increased vocalization, Coughing, Decreased, muffled, lung sounds, Dehydration, Diarrhea, Dryness of skin or hair, Dullness, Dysphagia, Dyspnea, Excitement, Fever, First degree atrioventricular heart block, Gallop rhythm, Generalized weakness, Heart murmur, Hyperesthesia, Hyphema, Increased respiratory rate, Increased strength of pulse, Laryngeal, tracheal, pharyngeal swelling, Matted or dirty hair, Muffled, decreased, heart sounds, Neck swelling, Neck weakness, Oily skin, hair or feathers, greasy, Polydipsia, Polyphagia, Polyuria, Propulsion, Retinal detachment, Retinal hemorrhage, Rough hair coat, Second degree atrioventricular heart block, Seizures or syncope, Sneezing, Steatorrhea, fatty stools, feces, Subcutaneous crepitation, Sudden death, Tachycardia, Trembling, Tremor, Underweight, poor condition, thin, emaciated, unthriftiness, ill thrift, Unusual or foul odor, stools, feces, Ventricular enlargement, Ventricular premature beat, Vomiting or regurgitation, Weak pulse, Weight loss
References   Vagney M. Survival times for cats with hyperthyroidism treated with a 3.35 mCi iodine-131 dose: a retrospective study of 96 cases. J Feline Med Surg 2018;20:528 [Web Reference]
Beatrice L. Concurrent endocrine neoplasias in dogs and cats: a retrospective study (2004–2014). Vet Rec 2018;182:323 [Web Reference]
Dickson D. Rapid assessment with physical examination in dyspnoeic cats: the RAPID CAT study. J Small Anim Pract 2018;59:75 [Web Reference]
Watson N. Clinicopathological features and comorbidities of cats with mild, moderate or severe hyperthyroidism: a radioiodine referral population. J Feline Med Surg 2018;Feb [Web Reference]
Peterson ME. Evaluation of Serum Symmetric Dimethylarginine Concentration as a Marker for Masked Chronic Kidney Disease in Cats With Hyperthyroidism. J Vet Intern Med 2018;32:295 [Web Reference]
Bree L. Prevalence and risk factors for hyperthyroidism in Irish cats from the greater Dublin area. Irish Vet J 2018;71:2 [Web Reference]
McLean JL. Prevalence of and risk factors for feline hyperthyroidism in South Africa. J Feline Med Surg 2017;19:1103 [Web Reference]
Peterson ME. Serum thyroxine and thyroid ­stimulating hormone concentration in hyperthyroid cats that develop azotaemia after radioiodine therapy. JSAP 2017;58:519 [Web Reference]
Vogelnest LJ. Skin as a marker of general feline health: Cutaneous manifestations of systemic disease. J Feline Med Surg 2017;19:948 [Web Reference]
Crossley VJ. Breed, Coat Color, and Hair Length as Risk Factors for Hyperthyroidism in Cats. J Vet Intern Med 2017;31:1028 [Web Reference]
Kopecny L. Management and monitoring of hyperthyroid cats: a survey of Australian veterinarians. J Feline Med Surg 2017;19:559 [Web Reference]
Miller ML. Thyroid Cysts in Cats: A Retrospective Study of 40 Cases. J Vet Intern Med 2017;31:723 [Web Reference]
Walter KM. Association of Polybrominated Diphenyl Ethers (PBDEs) and Polychlorinated Biphenyls (PCBs) with Hyperthyroidism in Domestic Felines, Sentinels for Thyroid Hormone Disruption. BMC Vet Res 2017;13:120 [Web Reference]
Bodey AL. Double-blinded randomised placebo-controlled clinical trial of individualised homeopathic treatment of hyperthyroid cats. Vet Rec 2017;180:377 [Web Reference]
Lucy JM. Efficacy of Low-dose (2 millicurie) versus Standard-dose (4 millicurie) Radioiodine Treatment for Cats with Mild-to-Moderate Hyperthyroidism. J Vet Intern Med 2017;31:326 [Web Reference]
Copyright © 2018 Cornell University College of Veterinary Medicine