Differential diagnosis and management of abnormal uterine bleeding due to hyperprolactinemia

Abnormal uterine bleeding may be acute or chronic accounting for up to 30% of outpatient visits to gynecologists. Hyperprolactinemia is one of the most common endocrine disorders associated with ovulatory dysfunction that results in menstrual irregularities. Prior to initiating treatment, the various causes (physiologic, pathologic, pharmacologic, or idiopathic) of hyperprolactinemia must be elucidated. Prolactin is a stress hormone that increases in response to stressful conditions; therefore, while collecting samples it is necessary to reduce venipuncture stress. A thorough patient history and physical examination will help to identify the cause and to direct therapy. Imaging results must always be assessed along with a patient’s clinical history and biochemical parameters when a pituitary tumor is suspected. Magnetic resonance imaging is the method of choice for the diagnosis of microprolactinomas and macroprolactinomas in both initial assessment and follow-up. Several drugs may cause a significant increase in serum prolactin concentration. If clinically feasible, the drug should be discontinued; if this is not possible, it should be substituted with a drug of similar action that does not cause hyperprolactinemia. Prolactinomas are the most common cause of pituitary adenomas affecting women of fertile age leading to significant elevations in prolactin that warrant treatment. Idiopathic hyperprolactinemia may be observed in the presence of elevated serum prolactin levels and in the absence of any other recognized cause of increased prolactin secretion. Dopamine agonists are the mainstay of therapy in prolactinomas and symptomatic idiopathic hyperprolactinemia because they normalize serum prolactin, effectively shrink prolactinomas and normalize gonadal function (i.e. menstruation).