Pituitary

Question 1

Endocrinological cause of low BP

Answer 1

Addison’s disease

Question 2

Anterior pituitary hormones

Answer 2

GH
Prolactin 
TSH
LH
FSH
ACTH

Question 3

What complication can a macroadenoma cause

Answer 3

May press on optic chiasm causing a bitemporal hemianopia

Question 4

Assessing for bitemporal hemianopia

Answer 4

Visual field assessment - Humphreys 30-2 test

Question 5

A CT scan of her pituitary shows a large (2cm) macroadenoma.

Her prolactin level comes back at 30,000 (normal <600). She has not had sexual intercourse.

Answer 5

Prolactionoma

Question 6

What prolactin level always indicated a prolactinoma

Answer 6

> 6000

Question 7

How is pituitary function assessed

Answer 7

Try to increase the levels of anterior pituitary hormones by:
Administer LHRH + TRH + stress

Question 8

What effect does hypoglycaemia have on the anterior pituitary

Answer 8

Increases CRF and thus ACTH

Increases GHRH and thus GH

Question 9

What is the triple test for anterior pituitary function

Answer 9

CPFT - hypoglycaemia, TRH (stimulates TSH and prolactin), LHRH

Question 10

Before conducting a triple test for pituitary function, what must you do first

Answer 10

Ensure no cardiac risk factors, angina and that ECG is normal (HYPOGLYCAEMIA can be dangerous)
No history of epilepsy
Ensure good IV access

Question 11

Why is good IV access necessary when doing a triple test for pituitary function

Answer 11

Hypoglycaemia can be dangerous:
When glucose low, first sympathetic activation occurs
When very low (<1.5mM) neurolycopenia may occur
Aggression can follow

Question 12

What glucose level are you aiming for in a triple test

Answer 12

<2.2mM

Question 13

When conducting a triple test for pituitary function, when do you do if severe hypoglycaemia occurs

Answer 13

Rescue patient with 50ml of 20% dextrose

This can be difficult to give to an aggressive patient, so a line must already be in place

Question 14

CPFT method

Answer 14

Fast patient overnight
Ensure good IV access
Weigh patient and calculate dose of insulin required (0.15u/kg)
Syringe contains: Insulin 0.15u/kg, TRH 200mcg, LHRH 100mcg
Give IV: patient will have a warm flush and may vomit

Take blood for glucose, cortisol, GH, LH, FSH, TSH, and prolactin every 30mins up to 60mins plus basal thyroxine
Check glucose, cortisol and GH up to 120mins

Question 15

What is a normal result in CPFT test

Answer 15

Glucose <2.2 (if not, give more insulin)
Cortisol reaches 550nM
GH reaches 10IU/L

Question 16

CPFT result if tumour pressing on pituitary

Answer 16

All cells may fail

Question 17

In a failing pituitary, what is most urgent to replace

Answer 17

Hydroxortisone 
Thyroxine 
Oestrogen 
GH
Prolactinoma treated with dopamine agonst: bromocriptine or cabergoline

Question 18

How does a non-functioning adenoma present on the pituitary

Answer 18

Press on the stalk and cause pituitary failure
Prevent dopamine reaching the pituitary
Thus cause hyperprolactinaemia

Question 19

What is urgently needed in a non-functioning adenoma pressing on the pituitary

Answer 19

Hydrocortisone needed urgently

No need for fludrocortisone