Hyperprolactinaemia

  • Most common biochemical disturbance of the pituitary
  • Presents earlier in women due to menstrual disturbance and late in men
  • Prolactin stimulates lactation
  • Raised levels lead to;
    • Secondary hypogonadism
    • Infertility
    • Osteoporosis
  • Its affects are due to inhibiting secretion of gonadotrophin releasing hormone resuling in low levels of FSH/LH and low testosterone or oestrogen levels
  • It is secreted from the anterior pituitary and its release is inhibited by dopamine
  • Hyperprolactinaemina may be caused by;
    • Excess production from the pituitary (prolactinoma)
    • Disinhibition by compression of the pituitary stalk reducing dopamine levels
    • Administration of a dopamine antagonist
  • Physiological causes;
    • Pregnancy, breast feeding, stress (post seizure)
  • Drugs
    • Phenothiazines, metachlopromide, haloperidol, ?-methyldopa, oestrogens
  • Diseases
    • Prolactinoma – micro or macroadenoma
    • Stalk damage – pituitary adenomas, trauma, surgery
    • Hypothalamic disease – crangiopharyngiomas, other tumours
    • Other causes – hypothyroidism (due to increased TRH), chronic renal failure (reduced excretion)
  •  

    Symptoms

    • Amenorrheoa/oligomenorrhoea, infertility, galactorrhoea
    • Reduced libido, increased weight
    • In men impotence, reduced facial hair
    • May also present late with osteoarthritis or local pressure effect from the tumour

     

    Tests

    • Basal PRL – non-stressful venopuncture between 9am and 4pm
    • Do a pregnancy test
    • TFT, U&Es
    • MRI pituitary

     

    Management

    • Dopamine agonists – bromocryptine or cabergoline
    • Microprolactinomas;
      • A tumour <10mm on MRI
      • Treat with dopamine agonist
      • Bromocriptine is generally used first line although it has more side effects e.g. nausea, depression , postural hypotension but is safer in pregnancy
      • If patient is not tolerant of the medication then transphenoidal surgery is indicated. The risks are tumour reoccurrence and permanent hormone deficiency
    • Macroadenoma
      • Shrink first with a dopamine agonist. Surgery is usually indicated if there are visual symptoms or pressure effects or if pregnancy is planed as 25% of macroadenomas expand during pregnancy
      • Bromocriptine and in some cases radiotherapy can be given post op as surgical resection is commonly incomplete

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    Disclaimer: These notes are my own personal study aid - DO NOT use them for medical advice!