Hyperthyroidism is the most common endocrine disorder in senior cats and, if treated appropriately, allows affected cats to maintain excellent quality of life for years.
Untreated hyperthyroidism causes progressive deterioration of cardiac function, muscle wasting, hypertension, and organ damage, significantly reducing quality and length of life. Early diagnosis through routine senior blood screening allows timely treatment before secondary complications develop. Radioactive iodine offers the best long-term welfare outcome, while daily medication is an appropriate alternative for cats where I-131 is inaccessible.