Hyperprolactinaemia Flashcards
Pituitary Disorder
What is hyperprolactinaemia?
Abnormally high levels of prolactin in the blood
What physiological causes can lead to hyperprolactinaemia?
Breastfeeding
Pregnancy
Stress
Sleep
How do drugs cause hyperprolactinaemia?
Any drugs that reduce dopamine will reduce inhibition of prolactin, increasing prolactin levels
Which drugs can cause hyperprolactinaemia?
- Dopamine antagonists (e.g. metoclopramide)
- Antipsychotics (e.g. phenothiazines)
What are the pathological causes of hyperprolactinaemia?
(1) Hypothyroidism
= increased TSH = increased prolactin
(2) Stalk compression from pituitary adenomas or other pituitary masses
(3) Stalk damage
= iatrogenic, road accident
(4) Prolactinoma
Why does increased prolactin lead to reproductive symptoms?
Increased prolactin decreases gonadotropin-releasing hormone (GnRH)
= leading to reduced sex hormone production
How do females with hyperprolactinaemia typically present?
- Galactorrhoea (30-80%)
- Menstrual irregularity (25%)
- Decreased libido
- Amenorrhoea
- Infertility
How do males with hyperprolactinaemia typically present?
- Impotence
- Visual field abnormalities
- Headaches
- Anterior pituitary malfunction
What investigations are done for suspected hyperprolactinaemia?
MAIN - Serum prolactin raised
Once physiological and drug causes have been excluded:
(1) Visual fields
= bitemporal temianopia
(2) Exclude primary hypothyroidism
(3) Assess anterior pituitary function
(4) MRI pituitary for prolactinoma
= if there are any clinical features of a pituitary tumour, and in all cases where prolactin is significantly raised
What is the first-line treatment for prolactinoma?
Dopamine agonists (usually cabergoline)
How does a dopamine agonist treat a prolactinoma?
Dopamine agonists work by stimulating dopamine receptors, which counteract the inhibitory effect of dopamine on prolactin secretion. This reduces prolactin levels, helps shrink the tumour, and restores normal pituitary function
What are the side effects of cabergoline?
(1) Fibrosis reactions
= Heart valve fibrosis
(2) Impulse control/psychiatric disturbances
= gambling
When is surgery considered for prolactinoma?
If the tumour does not shrink with dopamine agonists, transsphenoidal surgery or radiotherapy may be considered
What major group of painkiller medications can cause hyperprolactinaemia?
Opiates
What is the commonest type of pituitary tumour?
prolactinoma
What is the most common cause of hyperprolactinaemia?
prolactinoma
What effect can chronic hyperprolactinaemia have on the skeleton?
Osteoporosis
What class of drug is used to treat high prolactin levels?
Dopamine agonists eg. cabergoline, bromocriptine
What type of medication is Bromocriptine?
Short acting dopamine agonist
What types of antidepressants can cause hyperprolactinaemia?
SSRI’s and Tricyclic antidepressants
