Hyperthyroidism is the most common hormonal disorder of older cats, with several effective treatment options enabling good quality of life when appropriately managed over the long term.
Hyperthyroidism causes a state of chronic physiological overdrive that affects all body systems and causes discomfort that owners often mistake for increased vitality. Treatment dramatically improves quality of life by restoring metabolic normalcy. The unmasking of CKD after treatment is a genuine welfare challenge requiring careful monitoring. Radioactive iodine treatment provides permanent cure with a single treatment but requires brief isolation that has welfare costs. Medical management requires daily medication for life but avoids the isolation burden. Owner preference and cat temperament both appropriately influence treatment selection.