pituitary 010921

Question 1

Does pituitary failure cause hypotension

Answer 1

NO it is the loss of aldosterone that causes hypotension

Question 2

Signs of pituitary failure

Answer 2

galactorrhoea, amenorrhoea, bitemporal hemianopia

Question 3

combined pituitary function test (triple test)

Answer 3

GnRH/LHRH + TRH + insulin
insulin hypoglycaemic stress
TRH
GnRH/LHRH

Question 4

triple test method

Answer 4

 Fast patient overnight
 Ensure good IV access
 Weight pt. and calculate dose of insulin required (0.15U/kg  i.e. 70kg woman = 10.5U)
 Mix and IV. Inject the following (patient may vomit on injection):
• Insulin 0.15U/kg
• TRH 200mcg
• LHRH/GnRH 100mcg
 Take bloods at 0, 30 and 60 minutes of glucose, cortisol, GH, LH, FSH, TSH, prolactin and T4
 Take bloods at 90 and 120 minutes of glucose, cortisol and GH

Question 5

therapy for prolactinoma/pituitary failure

Answer 5

hydrocortisone first

then thyroixine, oestrogen, GH, cabergoline or bromocriptine

Question 6

prolactinoma level for diagnosis

Answer 6

> 6000

Question 7

pedisolone vs hydrocortisone

Answer 7

o Hydrocortisone is used as a steroid replacement in pituitary failure (BD or TDS)
o However, prednisolone is more potent with a longer half-life that is more resistant to degradation
o Prednisolone can be given OD and matches circadian rhythm better (will be used more in future)

Question 8

testing for acromegaly

Answer 8

o IGF-1 (produced by the liver in response to GH  promote tissue and bone growth)
o OGTT (75g of glucose  measure glucose in 2 hours)
 GH should drop with glucose
 In acromegaly, you get a paradoxical rise in GH with glucose administration
can also do IGF1 test

Question 9

treatment for acromegaly

Answer 9

o Pituitary surgery (the best treatment option)
o Pituitary radiotherapy
o Cabergoline
o Octreotide (somatostatin analogue; good at reducing the size of the tumour)