Hyperthyroidism is the most common hormonal disorder in older cats, causing significant welfare compromise through weight loss, anxiety, cardiac disease, and hypertension — yet it is highly treatable when diagnosed and managed appropriately.
Hyperthyroidism causes cats to live in a state of chronic metabolic excess — constantly hungry yet losing weight, anxious, restless, and at risk of heart failure and blindness. This prolonged deterioration is often gradual enough that owners adapt to the new normal without recognising the severity of welfare compromise. Diagnosis and treatment typically produce a rapid and dramatic improvement in quality of life that makes treating hyperthyroidism one of the most rewarding welfare interventions in feline medicine. Annual thyroid screening for senior cats ensures that diagnosis happens early, before secondary complications reduce treatment options and welfare outcomes.