Hyperprolactinemia.

Abstract

Prolactinomas are the most common pituitary tumors. Hyperprolactinemia is characterized by increased production of prolactin, often leading to reproductive dysfunction and galactorrhea. Prolactinomas may also cause male-factor infertility by producing hypogonadism. In addition, if large, they can produce neurologic symptoms by mass effect in the sellar area. The diagnostic evaluation first requires exclusion of other causes of hyperprolactinemia, such as pregnancy, primary hypothyroidism, numerous medications, and miscellaneous causes. The second step in the diagnostic evaluation is to perform a head scan, preferably an MRI. This is essential in order to exclude a "pseudoprolactinoma" which would require surgery. Following diagnostic evaluation, the next step is to determine whether a patient with hyperprolactinemia has an indication for therapy, such as a macroprolactinoma (tumor >1 cm), hypogonadism (risk of osteoporosis), infertility, significant galactorrhea, acne, hirsutism, or headache. The treatment of choice for nearly all patients with hyperprolactinemic disorders is medical. In most cases, dopamine agonists (bromocriptine, pergolide, cabergoline) are extremely effective in lowering serum prolactin, restoring gonadal function, decreasing tumor size, and improving visual fields. The main limitation is side effects, particularly nausea or orthostatic dizziness. The newest dopamine agonist, cabergoline, can be given just once or twice a week, is more effective in normalizing prolactin and restoring menses than bromocriptine, and is significantly better tolerated. However, it is not yet recommended as first-line therapy for patients seeking fertility, because adequate safety data in pregnancy are not available. For the infrequent patient unable to tolerate, or resistant to, medical therapy, neurosurgical transsphenoidal resection may be necessary, particularly if the patient has a large lesion jeopardizing the optic chiasm. Hyperprolactinemia is a rewarding disorder to manage because patients typically respond well to medication, with restoration of menses and fertility.