Pituitary

Question 1

Does hypopituitarism cause hypotension?

Answer 1

No

Question 2

Can you make aldosterone if the pituitary is shot?

Answer 2

If the pituitary gland fails, you can still produce aldosterone because the
adrenals are in tact - this will maintain normal blood pressure

Question 3

Which hormones come from the anterior pituitary?

Answer 3

GH (from GHRH)
Prolactin (stimulated by TRH and stopped by dopamine)
TSH (stimulated by TRH)
LH (stimulated by LHRH)
FSH 
ACTH (Stimulated by CRH)

Question 4

How do we look for pituitary failure?

Answer 4

Presents with galactorrhoea or amenorrhoea

Macroadenoma may cause bitemporal hemianopia

Question 5

When is a tumour inoperable?

Answer 5

if the tumour is in very close contact with the carotid arteries, it is
considered inoperable

Question 6

What negates a visual fields test?

Answer 6

In a visual field test, you must be able to see the blind spot or else the test has not been conducted properly

Question 7

What level of prolactin is no longer possibly physiological?

Answer 7

> 6000

Question 8

How do you test pituitary function with a prolactinoma?

Answer 8

Triple test:

Hypoglycaemia (ACTH/GH), TRH, LHRH

Question 9

What are the requirements for the Triple Test?

Answer 9

Ensure that there are no cardiac risk factors, or angina and that the ECG is normal

Ensure NO history of epilepsy

Ensure good IV access- at least 16G venflon

Question 10

How to you do the CPFT (triple test)?

Answer 10

o Fast the patient overnight

o Ensure good IV access

o Weigh patient and calculate dose of insulin required (0.15 units/kg)
• I.e. a 70 kg woman will need 10.5 units

o Mix the following in a 5 mL syringe:
• Insulin (0.15 units per kg or 0.2 for resistant)
• TRH 200 mcg
• LHRH 100 mcg

o Give intravenously
• Patients will have a warm flush and may vomit

o Take blood to measure:
• Glucose
• Cortisol
• GH
• LH and FSH
• TSH
• Prolactin
• This should be done every 30 mins up to 60 mins plus basal
thyroxine

o GLUCOSE, cortisol and GH should be checked up to 120 mins

Question 11

What is a normal response in the Triple test?

Answer 11

Quickly corrected hypoglycaemia

Raised prolactin

Cortisol > 550 nM

GH > 10 IU/L

Question 12

What must you replace if there is a tumour which reduces function?

Answer 12

Hydrocortisone

Thyroxine

Oestrogen

GH

(if prolactinoma - dopamine agonist needs to be given)

Question 13

What is disconnection hyperprolactinaemia?

Answer 13

Non functioning tumour causes hyperprolactinaemia

Question 14

Is prednisolone better than hydrocortisone for replacement?

Answer 14

Yeah - Longer half life, mimics circadian rhythm (one daily)

Question 15

For a child who may lack GH: what do you do?

Answer 15

DONT do a GH provocation/ ITT

Do random GH (and hope for a pulse) and then try exercise test (GH will release with exercise)

Question 16

Which tests can you use for acromegaly?

Answer 16

Oral glucose tolerance test

IGF-1 levels

Question 17

How big is a macroadenoma?

Answer 17

> 1cm

Question 18

Why may disconnection hyperprolactinaemia have lower prolactin than a prolactinoma?

Answer 18

• This is because compression of the pituitary stalk by the tumour can prevent
dopamine from reaching the pituitary
• This results in HYPERPROLACTINAEMIA
• Non-functioning adenomas need surgery because they will NOT respond to
dopamine agonists

Question 19

What may happen to the patient during the CPFT?

Answer 19

Initially, as the plasma glucose level starts to decrease, it will activate the
sympathetic nervous system (leading to sweating, tachycardia etc.)

When the glucose drops even further (< 1.5 mM), neuroglycopaenia may
occur and the patient may lose consciousness or become confused

Patients may also become AGGRESSIVE

A blood glucose < 2.2 mM is a good stimulus for the pituitary gland

From this point on wards, blood glucose has to be monitored closely

If SEVERE HYPOGLYCAEMIA occurs (and the patient is unconscious),
they should be rescued with 50 mL 20% dextrose

Question 20

What’s a normal response in the CPFT?

Answer 20

<2.2 mmol/L glucose at 30 mins

<600 prolactin

Question 21

Which replacement is urgent?

Answer 21

hydrocortisone

Question 22

What test do you test acromegaly with?

Answer 22

OGTT

Question 23

What is the treatments for acromegaly (in order)?

Answer 23

Surgery
Radiotherapy
Cabergoline
Octreotide