Chem Path - Pituitary Disease

Question 1

Prolactin is 8000, whats the diagnosis?

Answer 1

Prolactinoma

> 6000, always a prolactinoma

Question 2

Indication for triple test?

Answer 2

Tumour or post surgery

Question 3

What makes up the triple test?

Answer 3

GnRH, Insulin and TRH - each induce 2 hormones each

FSH - induced by GnRH
LH - induced by GnRH
TSH - induced by TRH
ACTH/Cortisol - induced by CRH which is induced by the hypo
GH - induced by GHRH which is induced by the hypo
Prolactin - induced by TRH

Test contraindicated in epilepsy, ischaemic heart disease and untreated hypothyroidism (as this inhibits GH and cortisol results)

Question 4

How to test for acromegaly?

Answer 4

Glucose tolerance test

Remember, a hypo induces GH for pituitary tests so giving glucose should suppress GH to 0.

However, with acromegaly, GH isn’t suppressed and therefore it can act against insulin, causing glucose to remain high.

After 2 hrs, if Glucose >7.8, acromegaly

Rx
Octreotide (somatostatin analogue)
Surgery