Hyperprolactinaemia

 

• Causes

  Pathological

  • Functional pituitary adenoma (prolactinoma).
  • Medication: antipsychotics, antidepressants, opiates.
  • Non-functional tumour blocking hypophyseal-portal tract ('stalk compression'), preventing hypothalamic inhibition of prolactin (PRL) release with dopamine.

  Pituitary adenomas

  • Common (10%) in population but symptoms are rare.
  • Usually micro (<10 mm), but some macro, which cause more symptoms.
  • Can secrete various hormones, most commonly PRL and GH.
  • May also lead to hypopituitarism by stalk compression → ↓GH, secondary hypogonadism, secondary hypothyroidism, secondary adrenal insufficiency, DI.

  Physiological

  • Pregnancy and lactation.
  • ↓Glucose
  • Illness: MI, surgery, stress.
  • Daily activities: exercise, eating, sex, sleep.

• Presentation

  Hypogonadotrophic hypogonadism (secondary hypogonadism):

  • Commonest presenting complaint of hyperprolactinaemia.
  • Due to interruption of pulsatile GnRH by ↑PRL, and possibly stalk compression.

  Hormonal symptoms:

  • Hypogonadism: sexual dysfunction, decrease libido, menstrual irregularities.
  • Hypopituitarism: other endocrine problems like hypothyroidism.
  • Galactorrhea: occurs in 90% of women and 10% of men. If gynecomastia is present, it is secondary to hypogonadism, as PRL itself does not increase breast growth in men.

  Pituitary adenoma mass effects:

  • Headache
  • Tunnel vision
  • CN palsy
  • Seizure

• Investigations

  • ↑PRL, especially in macro adenomas. However, elevation may be small when the cause is stalk compression, despite a big tumour on MRI.
  • β-hCG: rule out pregnancy and germ cell tumours.
  • MRI once other causes are ruled out.

• Management

  • Dopamine agonists – bromocriptine or cabergoline – are 1st line, and are effective at reducing symptoms and tumour size.
  • Surgery is only indicated in cases of medical failure or persistent visual field defects.