pituitary physiology and pathology

Question 1

what is the anterior pituitary also called and where does it derive from

Answer 1

Adenohypophysis - rathke’s pouch

Question 2

what is the posterior pituitary also called and where does it derive from

Answer 2

neurohypophysis - extension of neural crest

Question 3

what hormones does the ant pituitary secrete

Answer 3

ACTH, GNRH, TSH, prolactin, GH, FSH, LH, MSH

Question 4

what hormones does the post pituitary secrete

Answer 4

ADH and oxytocin

Question 5

what is the water deprivation test

Answer 5

stop water for several hours and test urine osmolarity (will not have changed) then give desmopressin (ADH) and allow normal drinking

Question 6

what water deprivation results would indicate a pituitary problem and a kidney problem

Answer 6

pituitary: urine concentrates after ADH.
Kidney: urine still not concentrated

Question 7

in the insulin stress test or glucagon test, what should hypoglycaemia cause a rise in

Answer 7

GH, ACTH and cortisol

Question 8

in the synthACTHen/ dexamthasone test what should happen to plasma cortisol after the injection

Answer 8

it should rise (if it does not adrenal problem, usually used for addisons)

Question 9

what size is a macroadenoma vs a microadenoma of the pituitary

Answer 9

macro = >1cm, micro <1cm

Question 10

what can macroadenomas compress if they are too big

Answer 10

compress optic chiasm, compress CNVIII, IV, V, VI

Question 11

what visual loss is associated with optic chiasm compression

Answer 11

bitemporal hemianopia

Question 12

what conditions can non-functioning pituitary adenomas cause from reduced hormone secretion

Answer 12

hypoadrenalism, hypothyroidism, hypogonadism, GH deficiency, (diabetes insipidus)

Question 13

how do you treat non-functioning pituitary adenomas

Answer 13

transsphenoidal surgery - replace hormones

Question 14

what effect does prolactin have on the body

Answer 14

breast milk production and breast growth

Question 15

what effect does prolactin have on GnRH

Answer 15

suppresses release of GnRH causing infertility and reduced libido

Question 16

what physiological causes increase prolactin

Answer 16

breast feeding and pregnancy (also stress and rise in sleep)

Question 17

what drugs can cause raised prolactin

Answer 17

dopamine antagonists eg metoclopramide (dopamine inhibits prolactin release)

Question 18

what is the most common functional pit tumour

Answer 18

prolactinoma

Question 19

what are symptoms of prolactinoma in females

Answer 19

early presentation, galactorrhoea, period irregularities, amenorrhoea, infertility, low libido

Question 20

what are symptoms of prolactinoma in males

Answer 20

late presentation, impotence, visual field disruption, impotence

Question 21

what investigations are done for prolactinoma

Answer 21

serum prolactin (high), MRI, visual field, pit function tests (decreased)

Question 22

how do you treat prolactinoma

Answer 22

dopamine agonists eg carbergoline

Question 23

what are side effects of dopamine agonists

Answer 23

N+V, low mood

Question 24

when would you surgically remove a prolactinoma

Answer 24

macroadenoma, failed drug

Question 25

what are symptoms of acromegaly (adenoma)

Answer 25

giantism, thickened soft tissue (jaw, skin, large hands, sweaty), snoring + sleep apnoea, hypertension, headaches, T2DM

Question 26

how do you diagnose acromegaly

Answer 26

serum GH, glucose tolerance test (giving glucose should suppress GH but will not affect acromegaly)

Question 27

what is first line treatment for acromegaly

Answer 27

surgery - radio less effective on its own

Question 28

what somatostatin analogues is used in acromegaly, what effect does it have, how do you give it, what are side effects

Answer 28

OCREATIDE: reduces GH and shrinks tumour/ sub cut injection monthly/ GI upset and GALLSTONES

Question 29

what dopamine agonist is used in acromegaly and is it effective

Answer 29

cabergoline - not V effective

Question 30

what GH antagonist analogues is used in acromegaly, what effect does it have, how do you give it

Answer 30

PEGVISOMAT: good response but does not give tumour, sub cut daily injections, last line as expensive

Question 31

what can cause pan hypopituitarism (10(

Answer 31

pit tumours, local brain tumours, iatrogenic, granulamtous (TB, sarcoidosis), vascular, trauma, mets, hypothalamic disease, autoimmune (Sheenan), infection (meningitis)

Question 32

what are symptoms of pan hypopituitarism

Answer 32

a lack of pit hormones: menstrual irregularities, impotence, obesity, loss of facial, axillary and pubic hair, dry skin, growth retardation (growth failure, hypothyroid, hypogonadism, hypoadrenalism, diabetes insipidus)

Question 33

how can you test for hypopituitarism

Answer 33

FPTs, hormone blood tests (testosterone, GH etc), synACTHen test and insulin tolerance

Question 34

what hormones are given when treating pan hypopituitarism

Answer 34

HRT: thyroxine, hydrocortisone, ADH, GH, sex steroids

Question 35

what is a benefit of giving GH in hypopituitarism and how do you give it

Answer 35

improves wellbeing, cardiac function, muscle mass, bone density, decreases cholesterol - SC daily injection

Question 36

what is a risk of giving testosterone in hypopituitarism and how do you give it

Answer 36

prostate enlargement, polycythaemia, hepatitis - give monthly IM injection

Question 37

what can cause diabetes insipidus

Answer 37

tumour, trauma, idiopathic

Question 38

what is diabetes insipidus and what are symptoms of it

Answer 38

ADH deficiency - polyuria, thirst, urine osmolarity similar to plasma osmolarity (not concentrates)

Question 39

how would you diagnose diabetes insipidus

Answer 39

water deprivation test

Question 40

how do you treat diabetes insipidus

Answer 40

desmopressin (ADH)