Cat Hyperthyroidism: Managing a Common Endocrine Disease for Welfare

Hyperthyroidism is the most common endocrine disease in older cats. Early diagnosis and effective treatment can restore quality of life and prevent serious complications.

Key Facts

Feline hyperthyroidism affects approximately 10% of cats over 10 years of age.
The condition causes weight loss despite increased appetite, hyperactivity, vomiting and hypertension.
Untreated hyperthyroidism leads to hypertensive retinal detachment, blindness, heart disease and death.
Four treatment options exist: medication, radioactive iodine, surgery and dietary iodine restriction.
Radioactive iodine is curative in over 95% of cases with a single treatment.
Regular thyroid palpation and blood testing at senior wellness checks enables early diagnosis.

Welfare Considerations

Feline hyperthyroidism causes progressive deterioration in quality of life that owners frequently attribute to normal ageing. The increased metabolic rate creates a state of chronic physiological stress — rapid heart rate, hypertension, gastrointestinal upset and muscle wasting — that the cat experiences as sustained discomfort. The systemic effects on heart and kidney function can be irreversible if treatment is delayed. With diagnosis and treatment, the majority of hyperthyroid cats achieve full remission and return to normal quality of life. Regular senior wellness screening including thyroid palpation and targeted blood tests enables early intervention before complications develop.

What You Can Do

Schedule regular six-monthly wellness checks for cats over 10 including thyroid assessment.
If your cat is losing weight despite good appetite, request thyroid testing promptly.
Discuss all four treatment options with your vet to select the most appropriate for your cat.
Monitor treated cats for concurrent kidney disease that may emerge post-treatment.
Advocate for thyroid screening to be part of every senior cat consultation protocol.