Pituitary Tumours Flashcards
(39 cards)
What is a functioning pituitary tumour affecting somatotrophs?
Acromegaly
What is a functioning pituitary tumour affecting lactotrophs?
Prolactinoma
What is a functioning pituitary tumour affecting thyrotrophs?
TSHoma
What is a functioning pituitary tumour affecting gonadotrophs?
Gonadotrophinoma
What is a functioning pituitary tumour affecting corticotrophs?
Cushing’s disease (corticotroph adenoma)
What is the pituitary tumour classification relating to function?
- Excess secretion of a specific pituitary hormone
eg prolactinoma - No excess secretion of pituitary hormone
(Non Functioning Adenoma)
What is the radiological (MRI) pituitary tumour classification relating to size?
Microadenoma <1cm (10mm)
Macroadenoma >1cm (10mm)
What are the radiological (MRI) pituitary tumour classifications?
- Sellar or suprasellar
- Compressing optic chiasm or not
- Invading cavernous sinus or not
How does a hyperprolactinaemia inhibit kisspeptin neurons?
- Prolactin binds to prolactin receptors on kisspeptin neurons in the hypothalamus
- Inhibit kisspeptin release
What is the result of a hyperprolactinaemia inhibiting kisspeptin neurons?
-Decrease in downstream GnRH/LH/FSH/T/Oest
- Oligo-amenorrhoea
- Low libido
- Infertility
- Osteoporosis
What is the presentation of prolactinomas?
- Menstrual disturbance
- Erectile dysfunction
- Reduced libido
- Galactorrhoea
- Subfertility
What are the other causes of an elevated prolactin?
- Physiological
- Pathological
- Iatrogenic
What are the other (physiological) causes of an elevated prolactin?
- Pregnancy/breastfeeding
- Stress: exercise, seizure, venepuncture
- Nipple/chest wall stimulation
What are the other (pathological) causes of an elevated prolactin?
- Primary hypothyroidism
- Polycystic ovarian syndrome
- Chronic renal failure
What are the other (iatrogenic) causes of an elevated prolactin?
- Antipsychotics
- Selective serotonin re-uptake inhibitors
- Anti-emetics
- High dose oestrogen
- Opiates
What must be excluded to confirm it is a ‘true’ (mild) elevation in serum prolactin?
- Macroprolactin
2. Stress of venepuncture
What is macroprolactin?
- ‘sticky prolactin’
- a polymeric form of prolactin
- an antigen–antibody complex of monomeric prolactin and IgG (normally <5% of circulating prolactin)
How do you exclude stress of venepuncture?
By a cannulated prolactin series
What is a cannulated prolactin series?
Sequential serum [prolactin] measurement 20 mins apart with an indwelling cannula to minimise venepuncture stress
What is the first line treatment of prolactinoma?
Dopamine receptor agonist - cabergoline
What is a pituitary tumour secreting excess GH referred to in children?
Gigantism
What is a pituitary tumour secreting excess GH referred to in adults?
Acromegaly
What are the symptoms of acromegaly?
- Sweatiness
- Headache
- Coarsening of facial features
- Macroglossia
- Prominent nose - Large jaw - prognathism
- Increased hand and feet size
- Snoring & obstructive sleep apnoea
- Hypertension
- Impaired glucose tolerance/diabetes mellitus
What is macroglossia?
Large tongue