Hyperprolactinemia: Diagnosis and treatment principles

Abstract

Prolactin (PRL) is a peptide hormone that consists of 198 aminoacids and synthesizes in lactotrophs which present about 20 % of cells in hypophysis. The levels of prolactin can be increased due to physical and psychological stress, temperature, increased physical activity, general anesthesia, acute coronary syndrome and meals. The secretion of prolactin is under tonic inhibitory control by hypothalamic dopamine. Prolactinomas are benign pituitary tumors of lactotrophs in adenohypophysis, with unknown etiology. Clinical symptoms and signs of hyperprolactinemia in women include amenorrhea, infertility, and galactorrhea, and decreased libido and visual impairment in men. Dopamine agonists decrease tumor mass in the majority of patients and are used as the primary therapy. The therapy should be initiated at a low dose, which should be increased slowly to minimize side effects, such as gastrointestinal symptoms and orthostatic hypotension. Pituitary function should be tested in patients with micro and macroadenomas until normalizing PRL level and recovering hypogonadism. Repeat MR of hypophysis and visual field testing are mandatory when tumors are adjacent to the optic chiasm. Dopamine agonists are not approved for use during pregnancy and should be discontinued once pregnancy occurs. A normal serum prolactin level is the goal in treating hyperprolactinemia, decreasing galactorrhea and symptoms of hypogonadism, as well as reduction of tumor mass. Dopamine agonists are recommended for first-line therapy and typically decrease both prolactin levels and tumor mass, thereby relieving symptoms.