Hyperthyroidism is the most common endocrine disorder in older cats. Effective treatment dramatically improves welfare, but ongoing management requires careful monitoring.
Untreated hyperthyroidism causes significant suffering including muscle wasting, hypertension-related complications, and cardiac disease. Treatment dramatically improves welfare, often transforming a declining cat into a thriving one. Post-treatment monitoring is critical because the kidneys, previously buffered by high blood flow from hyperthyroid state, may be stressed once thyroid function normalizes. Quality of life monitoring should incorporate appetite, weight, behavior, and blood pressure throughout treatment.