Hyperthyroidism, or an elevation in the level of thyroid hormone produced by the body, is one of the most common diseases of older cats. The thyroid gland is located in the neck and hyperthyroidism usually involves a benign growth in one or both sides of the gland though a cancerous growth in this area is also possible. Occasionally additional thyroid tissue can be found in other parts of the body which can complicate treatment.

Symptoms high thyroid levels include weight loss despite increased appetite, drinking/urinating more than normal, increased activity level or irritability, increased vocalisation or crying out at night and excessive grooming. Hyperthyroidism is easily diagnosed with a blood test.

Treatment options have increased in recent years (as has the incidence of the disease itself) and include tablets, a prescription diet, surgery or radioactive iodine therapy. Which option you choose depends not only on your cat’s temperament and any concurrent medical conditions but also your personal preferences and budget as the cost can vary significantly. Treatment occasionally causes hypothyroidism, or low thyroid hormone levels, which is easily fixed by a different type of medication.

Thyroid disease can affect the kidneys, blood pressure and heart among other things and can make the cat feel quite unsettled so if you suspect your cat may be hyperthyroid, speak with your vet about getting them tested.