Hyperthyroidism is the most common hormonal disorder in older cats, causing significant suffering when undiagnosed. Early recognition and treatment dramatically improves quality of life.
Hyperthyroidism causes a cascade of welfare-impairing effects: weight loss despite increased appetite creates chronic hunger alongside muscle wasting; elevated heart rate causes cardiovascular stress; hypertension damages kidneys and eyes. Affected cats often appear restless, vocal, and distressed. The welfare impact is severe yet entirely treatable. Many owners attribute weight loss and behavioral changes to normal aging, delaying diagnosis. Biannual wellness exams for senior cats — including thyroid palpation and blood screening — catch hyperthyroidism at earlier, more treatable stages.