Galactorrhoea

Galactorrhoea is milky nipple discharge unrelated to pregnancy or breastfeeding (or persisting more than 6 months after weaning), from one or both breasts.

• Causes: hyperprolactinaemia (pituitary prolactinoma and other sellar lesions, stalk compression, hypothyroidism, renal failure, cirrhosis, polycystic ovary syndrome, ectopic prolactin secretion), drugs, chest wall irritation, and idiopathic with normal prolactin.
• Drugs: antipsychotics (risperidone, haloperidol, chlorpromazine), metoclopramide, domperidone, antidepressants (tricyclics, SSRIs), methyldopa, verapamil, opioids, oestrogens and oral contraceptives, cimetidine, and cocaine.
• Prolactinoma is the commonest functioning pituitary adenoma; microadenomas (below 10 mm) occur mostly in women, macroadenomas in men.

Bilateral milky (multiple duct) discharge, expressed or spontaneous; breast tenderness.

• Hyperprolactinaemia features: oligomenorrhoea or amenorrhoea, infertility, low libido, vaginal dryness, osteopenia; in men erectile dysfunction, gynaecomastia and infertility.
• Mass effect of macroadenoma: headache, bitemporal hemianopia, cranial nerve palsies, hypopituitarism.
• Differential diagnosis: pathological nipple discharge (unilateral single duct, bloody or serous: intraductal papilloma, duct ectasia, carcinoma), physiological discharge, pregnancy, hypothyroidism, nipple stimulation, chest wall injury or herpes zoster, acromegaly.
• Complications: amenorrhoea and infertility, osteoporosis from hypogonadism, visual loss from macroadenoma, pituitary apoplexy, emotional distress.

Confirm milky character (fat globules on microscopy of discharge); exclude pregnancy; review medications.

• Serum prolactin (fasting, resting, without breast stimulation; repeat if mildly raised), thyroid stimulating hormone and free thyroxine, creatinine, liver profile, pregnancy test, gonadotropins and oestradiol, testosterone in men.
• Macroprolactin screening when prolactin is raised without symptoms; dilution for the hook effect in macroadenoma.
• Prolactin above 100 ng/mL (2000 mIU/L) suggests prolactinoma; 20 to 100 ng/mL occurs with drugs, hypothyroidism, stalk effect.
• Magnetic resonance imaging of the pituitary (with gadolinium) for persistent hyperprolactinaemia after excluding drugs and hypothyroidism; visual field testing and pituitary function tests for macroadenoma.
• Bloody or unilateral discharge needs breast imaging and ductal evaluation.

Supportive: reassurance, avoid nipple stimulation and tight clothing, stop drugs that cause it (psychiatric review before changing), observe if prolactin is normal and the patient is asymptomatic.

Pharmacological

• Drug induced: stop or substitute (for example aripiprazole 5 to 15 mg for risperidone) with the prescriber's agreement; check prolactin 2 to 3 weeks later.
• Hypothyroidism: levothyroxine 1.6 microgram/kg daily titrated to a normal thyroid stimulating hormone.
• Prolactinoma or symptomatic idiopathic hyperprolactinaemia: cabergoline 0.25 to 0.5 mg twice weekly, increasing by 0.25 mg every 4 weeks to prolactin control (usual 0.5 to 1 mg weekly, maximum 3 mg weekly); or bromocriptine 1.25 mg at night increasing to 2.5 mg two to three times daily (preferred when conception is planned).
• Cabergoline side effects: nausea, dizziness, postural hypotension, impulse control disorders; echocardiography for high doses.
• Macroadenoma with visual loss: a dopamine agonist is the initial treatment and shrinks the tumour rapidly.
• Hypogonadism with osteopenia: oestrogen replacement if dopamine agonist not effective.
• Pregnancy with microadenoma: stop dopamine agonist at confirmation; macroadenoma: continue bromocriptine and monitor visual fields.
• Withdrawal of the drug can be attempted after 2 years if prolactin is normal and tumour has shrunk or disappeared.

Procedures: transsphenoidal surgery for dopamine agonist resistance or intolerance, apoplexy or progressive visual loss; radiotherapy for residual aggressive tumour.

Special groups: women wishing pregnancy (bromocriptine, monitor), postmenopausal women (treat only if macroadenoma), men (testosterone replacement if dopamine agonist fails), psychiatric patients (specialist liaison).

Red flags: visual field defect, severe headache, bloody unilateral discharge, prolactin above 200 ng/mL (4000 mIU/L), pituitary mass, pituitary apoplexy.

Follow-up: prolactin every 3 months until controlled, then yearly; MRI at 6 to 12 months and then as needed; visual fields if macroadenoma; bone density.