Hyperthyroidism is the most common endocrine disorder of cats, primarily affecting animals over 10 years. Early diagnosis and effective treatment prevent significant suffering and extend quality life.
Feline hyperthyroidism represents one of the most satisfying welfare interventions in companion animal medicine because it is common, causes significant suffering when untreated, and responds well to several effective treatments. The chronically elevated metabolic rate of hyperthyroid cats produces a state of physiological distress — racing heart, weight loss despite constant hunger, and extreme restlessness or anxiety. Hypertension develops and damages kidneys, eyes and the heart over months if untreated. Early detection through annual veterinary screening of cats over 7 years allows treatment before serious secondary damage occurs. Radioactive iodine is the gold standard treatment where available, providing a permanent cure with a single treatment.