FELINE HYPERTHYROIDISM

Hyperthyroidism is a common disorder of the older cat. It is characterized by excessive production of thyroid hormones by the thyroid gland. The thyroid gland has two lobes that are located on either side of the neck.

Typically cats suffer from weight loss, increased appetite and water consumption and increased amount of urine production, occasionally cats present nervousness, gastrointestinal signs (diarrhea, vomiting) and hair loss amongst others.

Treatment of hyperthyroidism consists in lowering the concentration of circulating thyroid hormone (T4) either medically (reversible) or surgically/radioiodine therapy (permanent). The choice usually depends on concurrent conditions and age of the patient. Medical treatment administering tablets twice daily is usually the initial treatment. If there are no complications (like renal failure which also is a common disorder in the older cat and can sometimes be unmasked after starting treatment for hyperthyroidism) after stabilization with medical treatment it is usually safe to proceed with a more permanent treatment option.

Medical treatment consists of administering a drug (Methimazole) that blocks thyroid hormone synthesis. This drug is usually given twice daily in order to achieve optimal response. Initial monitoring of kidney and liver function, complete blood count and T4 levels is important to discover and treat any possible side effects and treatment complications.