September 24, 2017
Hyperprolactinaemia Minimize

Hyperprolactinaemia

Hyperprolactinaemia is physiologically normal during pregnancy and lactation. Outside these states, the commonest non-drug causes of hyperprolactinaemia are stress, microprolactinomas, polycystic ovary syndrome and primary hypothyroidism. Women present with infertility, galactorrhoea or menstrual irregularities and unusually with the mass effect of tumour spreading outside the pituitary fossa. Whereas men tend to present later with the effects of larger tumours, such as sexual dysfunction or the space-occupying effect of the pituitary tumours.

The normal pattern of prolactin in pregnancy is for a gradual rise during the first two trimesters followed by a brisk rise in the third trimester to 6000-10,000 mU/L. Prolactin remains elevated during lactation but gradually falls to normal with prolonged breasts feeding.

Notes

  • Prolactin may be elevated in patients with renal or liver disease but this should not alter management regarding the need to image the pituitary gland.
  • The choice of 800 mU/L as a threshold for imaging the pituitary is a compromise and will be effected by clinical features; for example, in women with galactorrhoea/oligomenorrhoea use a sustained value greater than 600 mU/L whereas in asymptomatic patients a threshold of 1000 mU/L may be more appropriate.
  • Stress is a recognised cause of mild hyperprolactinaemia and under these circumstances repeated samples, taken through an indwelling cannula, over an hour will show a fall.
  • Prior to investigating patients for pituitary tumours, hypothyroidism should always be excluded as a cause of hyperprolactinaemia.
  • Hyperprolactinaemia may be due to macro forms of prolactin due to complexes with immunoglobulins and not to a pituitary tumour.
  • If hyperprolactinaemia is thought to be drug induced, medication should be withdrawn and prolactin measured 4-6 weeks later.

Drugs causing hyperprolactinaemia

  • Dopamine receptor agonists
  • Neuroleptics (19% of schizophrenics on neuroleptic agents have galactorrhoea
  • Anti-emetics: metoclopramide, domperidone
  • SSRI (selective serotonin reuptake inhibitors)
  • Tricyclic antidepressants (rare)
  • Cardiovascular drugs: verapamil, reserpine, methyldopa
  • Highdose oestrogens
  • Opiates
  • Miscallaneous: bezafibrate, omeprazole, trimethoprim, histamine H2 antagonists

  

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