Acromegaly

Acromegaly is a disorder marked by progressive enlargement of the head, face, hands, and feet due to excessive secretion of somatotropin (growth hormone).

Chronic overproduction of growth hormone in man and the cat is most often caused by a GH-producing tumor of the pituitary gland. In dogs the usual cause is quite different and the disorder is reversible.

Signs of Acromegaly

Clinical signs include gait abnormalities consisting of chronic progressive stiffness and rigidity. Other symptoms are increased appetite associated with weight gain, excess urination (polyuria) and increased thirst (polydipsia), excessive panting, progressive thickening of the skin, prominent skin folds, noisy breathing and enlargement of the tongue.

Diagnosis of Acromegaly

A definitive diagnosis requires measurement of increased plasma growth hormone or insulin-like growth factor 1 (IGF-1) concentrations in suspected cases.

Treatment of Acromegaly

Acromegaly is encountered in intact female dogs that were treated with progestagens to prevent estrus and in dogs during diestrus (period of sexual inactivity). Progestagen withdrawal and/or ovariohysterectomy will result in a reduction of plasma GH and GH-dependent insulin-like growth factor concentrations and appreciable clinical improvement.

Feline Acromegaly

Feline acromegaly is most commonly caused by a functional pituitary tumor. Definitive diagnosis can be difficult because of the gradual disease onset, subtle clinical signs, unavailability of relevant laboratory tests, and client financial investment. The most significant clinical finding of acromegaly is the presence of insulin-resistant diabetes mellitus. Diagnosis is currently based upon brain imaging and measurement of serum GH and/or insulin-like growth factor-1 concentrations. Definitive treatment in cat is not well described, but radiation therapy appears promising.