Hyperprolactinaemia

Abnormally high levels of prolactin in the blood

Aetiology

Physiological

  • Breastfeeding
  • Pregnancy
  • Stress
  • Sleep

Drugs

  • Any drugs which reduce dopamine will reduce inhibition of prolactin so increase prolactin levels
    • Dopamine antagonists e.g. metoclopramide
    • Antipsychotics e.g. phenothiazines
    • Less commonly: antidepressants e.g. TCA, SSRIs, oestrogens, cocaine

Pathological

  • Hypothyroidism
  • Stalk compression due to pituitary adenomas and other pituitary masses
  • Damage to stalk - iatrogenic, road accident
  • Prolactinoma

Clinical presentation

  • Patients may present with features of hyperprolactinaemia or structual symptoms from a pituitary tumour with headaches and visual loss (latter presentation more common in males)

Females - early presentation

  • Galactorrhoea (30-80%)
  • Menstrual irregulatity (25%)
  • Decreased lipido
  • Ammenorrhoea
  • Infertility

Males - late presentation

  • Impotence
  • Visual field abnormal
  • Headaches
  • Anterior pituitary malfunction

Investigations

  • Serum prolactin raised
  • Once physiological and drug causes have been excluded:
    • Visual fields - bitemporal temianopia
    • Exclude primary hypothyroidism
    • Assess anterior pituitary function
    • MRI pituitary if there are any clinical features of a pituitary tumour, and in all cases where prolactin is significantly raised

Management - Prolactinoma

Dopamine agonists

  • Usually cabergoline (Dostinex)
  • Normalises prolactin and shrinks tumour in the vast majority - very rarely consider surgery because of this
  • If tumour does not shrink consider transsphenoidal surgery or radiotherapy