Hyperthyroidism is the most common endocrine disease in older cats and causes significant suffering if undiagnosed and untreated.
Cats with untreated hyperthyroidism suffer progressive weight loss despite increased appetite, creating a distressing hunger-malnutrition paradox. Cardiac effects including hypertrophic cardiomyopathy cause secondary heart failure. Hypertension causes retinal detachment and blindness. Early detection through blood screening enables treatment that restores quality of life rapidly.