Feline hyperthyroidism is one of the most common endocrine diseases in older cats - dietary management with iodine restriction is an emerging welfare-positive treatment option.
Hyperthyroid cats experience significant chronic welfare compromise - weight loss despite increased appetite, restlessness, cardiac stress, and gastrointestinal upset. Early diagnosis through annual blood testing in cats over 10 years enables treatment before complications develop. Radioactive iodine treatment (I-131) is curative with minimal ongoing welfare impact and is increasingly accessible. Methimazole provides medical management but requires twice-daily medication that some cats resist, causing daily handling stress. Dietary management works in compliant cats and avoids medication stress. Monitoring treated cats for concurrent CKD (which hyperthyroidism can mask) is essential.