Monday, 20 September 2010

MRCP revision battle 16.6: Prolactin

Prolactin is a hormone released from the anterior pituitary.
It is under the negative control of dopamine (ie dopamine prevents its release)

Raised prolactin causes a drop in GnRH, LH, oestrogen and testosterone levels.

Symptoms/signs of raised prolactin include:
  • galactorrhoea
  • decreased libido
  • amenorrhoea
  • infertility

Note that gynaecomastia is NOT associated with raised prolactin.

Causes of a raised prolactin include:
  • physiological causes
    • pregnancy
    • breast feeding/nipple stimulation
    • stress
    • post-fit
    • exercise
  • drugs
    • phenothiazides
    • metoclopramide
    • methyl-dopa
    • haloperidol
    • oestrogens
  • metabolic causes
    • hypothyroidism
    • PCOS
    • acromegaly (1/3)
    • chronic renal failure
  • disease
    • prolactinoma
      • microprolactinoma (<10mm) release more prolactin than macroprolactinomas
    • compression of pituitary stalk removing dopamine control

Treatment is with bromocriptine.
It is best to give it in the evening as it causes postural hypotension

Very nearly there.  Last battle of the day will be Erbs palsy....