Hyperthyroidism is the most common hormonal disorder in older cats, causing significant distress and health decline if untreated, but responding well to multiple treatment options.
Hyperthyroid cats experience a distinctly uncomfortable state — perpetually anxious, uncomfortable, losing weight despite hunger and increasingly compromised by cardiovascular effects. This makes effective treatment a significant welfare priority. The good news is that all major treatment options produce substantial improvements in quality of life when implemented appropriately. The choice between radioactive iodine, medication and dietary management should consider each cat's individual circumstances and the owner's capacity for care.