Pituitary

Question 1

what are the hypothalamic hormones in the HP axis?

Answer 1

GHRH
GnRH
TRH
Dopamine
CRH

Question 2

what actions do the hypothalamic hormones have on the anterior pituitary respectively

Answer 2

-GHRH - stimulates GH
-GnRH - stimulates Lh & FSH
-TRH - stimulates TSH & prolactin
-dopamine - inhibits prolactin
-CRH - stimulates ACTH

Question 3

does pituitary failure cause hypotension

Answer 3

no, because this is controlled by aldosterone which has nothing to do with the pituitary

Question 4

what is the combined pituitary function test (CPFT)?

Answer 4

triple test where GnRH, TRH & insulin are given (for stress) and measure levels of pituitary hormones every 30 mins for 1 hour. glucose cortisol and GH up to 2 hours

Question 5

what hormones are given in CPFT

Answer 5

inducing the gland
insulin, TRH, GnRH (LHRH)

Question 6

contraindications to combined pituitary function test

Answer 6

IHD
epilepsy
untreated hypothyroidism (impairs GH & cortisol response)

Question 7

side effects of CPFT?

Answer 7

hypoglycaemia side effects
TRH injection may cause transient metallic taste in mouth, flushing & nausea

Question 8

what should happen to glucose in CPFT?

Answer 8

should go below 2.2 mmol/L or else it wont work to increase ACTH & GH

Question 9

what are the normal values for each hormone in CPFT

Answer 9

GH > 3
cortisol >450
LH/TSH/FSH >10

Question 10

how are pitutary tumours categorised?

Answer 10

microadenoma (<10mm) and macro-adenoma (>10mm)

Question 11

differences between microadenoma and macroadenoma?

Answer 11

microadenoma (<10mm) - usually non functional but can sometimes cause hyperprolactinaemia due to dopaminergic neurones being squashed, benign

macroadenoma (>10mm): usually functional, may be aggressive

Question 12

what visual field defect in pituitary adenoma

Answer 12

bitemporal hemianopia (compresses optic chiasm)

Question 13

what does prolactin count of >6000 indicate

Answer 13

prolactinoma

Question 14

what does mild elevation of prolactin <1000 indicate

Answer 14

stress, breast exam, vaginal exam, hypothyroidism, PCOS

Question 15

what does moderate elevation of prolactin (1000-5000) indicate

Answer 15

hypothalamic tumour, non functioning adenoma compressing stalk, PCOS, drugs (dompiredone, phenothiazines)

Question 16

how do you manage prolactinoma?

Answer 16

1) DA antagonists = cabergoline, bromocriptine
2) transphenoidal surgery

Question 17

what is the most common symptom in acromegaly

Answer 17

HTN

other - diabetes, soft tissue growth, colonic polyps

Question 18

gold standard investigation for acromegaly?

Answer 18

oral glucose tolerance test (OGTT) (doesnt suppress GH release in acro)

Question 19

what is used to monitor acromegaly after diagnosis?

Answer 19

serum IGF1 (raised)

Question 20

why is colonsocopy important in those with acromegaly

Answer 20

risk of colonic polyps

Question 21

management of acromegaly?

Answer 21

1) transphenoidal surgery
2. pituitary radiotherapy
3. cabergoline (cos acro might come from lactotrophs)
4. ocreotide (expensive) - somatostatin analogue cant be stopped when started
5. pegvisomant

Question 22

difference in management of prolactinoma vs acromegaly?

Answer 22

prolactinoma: meds then surgery
acromegaly: surgery then meds if needed

Question 23

causes of hypopituitarism?

Answer 23

malignancy, infection (TB, syph), sarcoid + lymphoma, iatrogenic, infarct (sheehans PPH), pituitary apoplexy, kallmans

Question 24

what gene might lead to hypopituiarism

Answer 24

PROP1
-involved in dev and function of anteiror pituitary

Question 25

symptoms of hypopituitarism

Answer 25

lethargy, SD, addisonian crisis, myxoedema

Question 26

how do you treat hypopituitarism

Answer 26

replace end hormones - HYDROCORTISONE FIRST
2) thyroxine
3) oestrogen/testosterone
4) GH if needed