Cat Hyperthyroidism: Symptoms, Diagnosis, and Treatment

Hyperthyroidism is the most common hormonal disorder in older cats, and one of the most treatable.

Who Gets It?

Almost exclusively cats over 10 years. Affects approximately 10% of cats over 10.

Signs

• Weight loss despite increased appetite
• Increased thirst and urination
• Hyperactivity or restlessness
• Poor, unkempt coat
• Rapid or irregular heart rate

Treatment Options

• Medication (methimazole): daily tablet or gel. Effective and reversible.
• Radioactive iodine (I-131): curative in 95% of cases. Gold standard.
• Surgery: removal of the thyroid gland

Prognosis

Excellent with treatment. Most cats live for years after diagnosis.