Hyperthyroidism is the most common endocrine disorder in older cats, causing significant suffering if untreated but responding well to multiple treatment options.
Untreated hyperthyroid cats experience chronic weight loss despite ravenous appetite, elevated heart rate, hypertension, and progressive organ damage. Many cats appear anxious and restless. Without treatment, cardiac complications, kidney disease, and liver problems develop. Treatment significantly improves quality of life, with radioactive iodine providing the highest cure rates. Early detection through routine veterinary blood testing is essential for older cats.