2) Hypersecretion of APG hormones

Question 1

What is the most common cause of hyperpituitarism?

Answer 1

Tumours

• pitutary
• ectopic-from non-endocrine tissue elsewhere in body

Question 2

What is hyperpituitarism commonly linked to?

Answer 2

Bitemporal hemniaopia

• PG compresses optic chiasm
• loss of peripheral vision + headache

Question 3

What does an excess of each APG hormone cause?

Answer 3

Excess ACTH=Cushing's syndrome
Excess TSH=Thyrotoxicosis
Excess LH/FSH=precocious puberty
Excess prolactin=Hyperprolactinaemia
Excess GH=gigantism/acromegaly

Question 4

How is prolactin release normally controlled?

Answer 4

Inhibitory regulation by dopamine

Question 5

Where is prolactin normally secreted from?

Answer 5

lactotrophs in APG

Question 6

Physiological reasons prolactin levels may be high?

Answer 6

Pregnancy

Breast feeding

Question 7

Pathological reasons prolactin levels may be high?

Answer 7

Prolactinoma (pituitary adenoma)

Question 8

What can hyperprolactinaemia cause?

Answer 8

Loss of libido
Secondary amenorrhoea
Erectile dysfunction
Galacttorhoea (women)

Question 9

What is the link between hyperprolactinaemia with FSH/LH?

Answer 9

High levels of prolactin suppress GnRH pulsatility which reduces LH/FSH levels

Question 10

How is hyperprolactinaemia treated?

Answer 10

D2 receptor antagonist e.g. bromocriptine/cabergoline to mimic dopamine suppression of prolactin release

Question 11

3 Side effects of D2 receptor agonists?

Answer 11

Pathological gambling
Postural hypotension
Nausea/vomiting

Question 12

What cells in the APG secrete GH?

Answer 12

Somatotrophs

Question 13

What is GH excess called in children vs adults?

Answer 13

Children=gigantism

Adults=acromegaly

Question 14

What is the main cause of GH excess?

Answer 14

Pituitary adenoma-somatotrophs

Question 15

What type of tissue grows more in acromegaly?

Answer 15

Soft tissue

Question 16

What type of onset does acromegaly have?

Answer 16

Slow

Question 17

2 hallmark signs of acromegaly & what do they indicate?

Answer 17

Sweating
Headache

Indicate active disease

Question 18

List clinical features of acromegaly:

Answer 18

Sweating
Headache

Barrel chest
Coarsness of facial features
Mandible grows-lower jaw protrusion
Spaceshaped hands
Macroglossia
Carpel tunnel syndrome
Bitemporal hemniopia

Question 19

5 possible complications of acromegaly

Answer 19

Diabetes mellitus-GH is a stress hormone so tries to increase BGC
Obstructive sleep apnoea
Hypertension
Cardiomyopathy
Increased cancer risk

Question 20

Acromegaly treatment:

Answer 20

Surgery
Radiotherapy
Somatostatin analogues
D2R agonists-many GH tumours express D2R

Question 21

What is the link between acromegaly + prolactin?

Answer 21

GH tumours often co-secrete prolactin

Question 22

How is acromegaly diagnosed?

Answer 22

1) Elevated IGF-1

2) OGTT-paradoxical GH rise after glucose given

Question 23

Why can’t we simply measure GH levels to diagnose acromegaly?

Answer 23

GH release is pulsatile

Question 24

What normally happens to GH when glucose increases vs what happens in acromegaly?

Answer 24

GH=stress hormone which tries to increase BGC

Normal-increased glucose reduced GH production
Acromegaly-GH increases with glucose (PARADOXICAL)

Question 25

Why might someone with acromegaly have glucose in their urine?

Answer 25

Excess GH increases glucose production=renal threshold exceeded