Hyperprolactinemia

Definition

Hyperprolactinemia is a condition characterized by elevated serum prolactin levels, which can lead to hypogonadism, infertility, and galactorrhea. It may result from physiological, pathological, or pharmacological causes.

Epidemiology

• Most common pituitary hormone disorder after pituitary adenomas
• More frequent in women of reproductive age
• Prevalence: up to 0.4% in the general population, higher in women with reproductive dysfunction
• Prolactinomas account for ~40% of pituitary adenomas

Etiology

• Physiological: pregnancy, lactation, stress, sleep
• Pathological: prolactin-secreting pituitary adenoma (prolactinoma), hypothalamic disease, pituitary stalk compression
• Pharmacological: antipsychotics, antidepressants, metoclopramide, estrogens
• Other endocrine disorders: hypothyroidism, chronic kidney disease, cirrhosis

Pathophysiology

• Dopamine normally inhibits prolactin secretion via D2 receptors in lactotrophs
• Loss of dopaminergic inhibition (stalk compression, drugs) → elevated prolactin
• Prolactin excess → inhibition of GnRH → hypogonadotropic hypogonadism → menstrual irregularities or sexual dysfunction
• Chronic prolactin elevation may cause galactorrhea, infertility, bone loss