GALACTORRHEA

Definition and Presentation

• Galactorrhea = Inappropriate milky discharge from breasts (in a woman not postpartum or >6 months after childbirth, not breastfeeding).
• Usually bilateral, spontaneous or expressible; may be unilateral but less common.
• Rare in men.
• Often traces back to postpartum lactation that never fully ceased.

Normal Physiology of Lactation

1. Hormonal Requirements
   • Prolactin (anterior pituitary)
   • Estrogen & Progesterone (ovaries) for duct/lobule development.

1. Pregnancy-Related Changes
   • Blood prolactin progressively increases, peaking at delivery (~10× normal upper limit).
   • Rising estrogens stimulate prolactin secretion (pituitary lactotroph stimulation).
2. Suckling Action
   • Stimulates prolactin release (milk production) and oxytocin release (myoepithelial contraction → milk let-down).
3. Dopamine Inhibition
   • Dopamine (prolactin-inhibiting factor) from hypothalamus → pituitary lactotrophs → suppresses prolactin secretion.

CAUSES OF GALACTORRHEA

1. Hyperprolactinemia-Related

• Common Pathway: Excess prolactin often → galactorrhea.
• Hypothalamic/Pituitary Stalk Lesions or Macroadenomas
  • Interfere with dopamine transmission → loss of prolactin inhibition → elevated prolactin.
• Prolactinoma (pituitary tumor secreting prolactin)
  • Often presents with galactorrhea, amenorrhea.
• Dopamine Antagonists (psychiatric or GI drugs)
  • e.g., risperidone, phenothiazines, metoclopramide → block dopamine effects → ↑ prolactin.
• Primary Hypothyroidism
  • ↑ TRH → stimulates pituitary lactotrophs → hyperprolactinemia.
• Chronic Renal Failure
  • ↑ prolactin secretion + decreased clearance.

2. Nipple/Chest Wall Stimulation or Lesions

• Chronic Nipple Stimulation (e.g., mechanical, frequent self-exam).
• Chest Wall Injuries or surgeries, thoracotomy, herpes zoster on chest.
• Spinal cord lesions (cervical region).
• Mechanism: Mimics suckling → triggers reflex prolactin release.

3. GH Excess (Acromegaly)

• ~50% of women with acromegaly have galactorrhea (GH has lactogenic activity) → can occur even without hyperprolactinemia.

4. End-Organ Breast Hypersensitivity

• Most common single cause (~50% of galactorrhea cases).
• Normal serum prolactin; regular menses.
• Often postpartum: lactation fails to stop completely even when menses resume.

5. Other Rare Situations

• Usually mild or minimal contribution unless hyperprolactinemia present.

TREATMENT AND MANAGEMENT

1. Address Underlying Hyperprolactinemia
   • Dopamine agonists (bromocriptine, cabergoline) for prolactinomas → normalize prolactin, resolve galactorrhea.
2. When Pituitary Tumors Are Nonfunctioning
   • Dopamine agonists reduce prolactin (stalk effect) but do not treat tumor mass; surgical/other interventions may be necessary.
3. Medication-Related
   • If a drug induces hyperprolactinemia, consider alternative therapy.
4. Nonhyperprolactinemic (Idiopathic) Galactorrhea
   • Usually benign; reassurance ± supportive measures as needed.

Download Lecture Slides for Hyperprolactinemia/Prolactinoma