pituitary tumours

Question 1

physiological cause of elevated prolactin

Answer 1

Pregnancy/breastfeeding
Stress: exercise, seizure, venepuncture
Nipple/chest wall stimulation

Question 2

pathological cause of elevated prolactin

Answer 2

Primary hypothyroidism
PCOS(Polycystic ovarian syndrome)
Chronic renal failure

Question 3

iatrogenic cause of elevated prolactin

Answer 3

Antipsychotics
Selective serotonin re-uptake inhibitors
Anti-emetics
High dose oestrogen
Opiates

Question 4

prolactinoma treatment and how the first line work?

Answer 4

1. dopamine receptor agonist (cabergoline)
2. trans-sphenoidal pituitary surgery

how it works:
1. lactotroph (with D2 receptor) release prolactin.
2. dopamine binds to D2 receptor- prevents prolactin release
3. as do D2 receptor agonist

Question 5

2 main symptom/sign for acromegaly

Answer 5

sweatiness/headache

(other not easy to guess ones:
OSA, hypertension, DM)

Question 6

how to diagnose acromegaly

Answer 6

-GH pulsatile so random measurement unhelpful.

-Elevated serum IGF-1

-Failed suppression (‘paradoxical rise’) of GH following oral glucose load – oral glucose tolerance test

-Once confirm GH excess, pituitary MRI to visualise pituitary tumour

Question 7

treatment for acromegaly

Answer 7

untreated=increase cardiovascular risk
1. trans-sphenoidal pituitary surgery

2. to shrink tumour prior to surgery use:
   a) somatostatin analogue (octreotide)
   b)dopamine agonist (cabergoline)
3. radiotherapy= slow

Question 8

tests for cushing’s disease

Answer 8

1. elevated 24hrs urine free cortisol
2. elevated late night cortisol in salivary/blood
   3.failure to suppress cortisol after oral dexamethasone

Question 9

ACTH dependent vs independent

Answer 9

dependent:
1. cushing’s (pituitary corticotroph adenoma)
2.ectopic ACTH (lung cancer)

independent
1. steroid by mouth
2. adrenal adenoma/carcinoma

Question 10

what is non functioning pituitary adenoma

Answer 10

no excess pituitary hormone secretion
often present with bitemporal hemianopia
-serum prolactin can be raised as dopamine can’t travel down stalk

-trans-sphenoidal surgery