Hyperprolactinemia
Hyperprolactinemia -- elevated serum prolactin -- is the most common pituitary hormone disorder. It disrupts the reproductive axis in both men and women, causing hypogonadism, infertility, and -- in women -- galactorrhea and menstrual irregularity. Most cases are caused by a benign prolactin-secreting pituitary adenoma (prolactinoma) or by medications.
Symptoms
In women: irregular or absent periods, infertility, milky nipple discharge (galactorrhea), decreased libido, and vaginal dryness. In men: decreased libido, erectile dysfunction, infertility, and -- in large adenomas -- headache and visual field defects from optic chiasm compression.
Causes and risk
Prolactinoma (pituitary adenoma) is the most common endogenous cause. Medications -- dopamine antagonists (antipsychotics, metoclopramide), SSRIs, opioids, and certain antihypertensives -- are the most frequent cause overall. Hypothyroidism and chronic kidney disease also raise prolactin through different mechanisms.
How it is evaluated
Fasting morning prolactin is measured twice to confirm elevation (stress, recent breast stimulation, or phlebotomy can transiently elevate levels). TSH is checked to exclude hypothyroidism. Pituitary MRI with gadolinium is obtained when prolactin is significantly elevated or a structural cause is suspected.
Treatment
Dopamine agonists (cabergoline, bromocriptine) are first-line -- they suppress prolactin, shrink tumors, and restore gonadal function in the majority of patients. Cabergoline is preferred for tolerability and efficacy. Surgery is reserved for resistance to medical therapy, very large tumors, or vision compromise. Medication-induced hyperprolactinemia is managed by switching the offending drug when possible.