hyposecretion of anterior pituitary hormones

Question 1

different parts of pituitary

Answer 1

anterior (glandular) and posterior (neural- derived from diencephalon)

Question 2

anterior pituitary hormones

Answer 2

FSH/LH prolactin GH TSH ACTH

Question 3

classification of disorders

Answer 3

primary endocrine is issue with endocrine gland, secondary is issue with anterior pituitary

Question 4

define panhypopituitarism

Answer 4

decreased production of all anterior pituitary hormones

Question 5

cause and features of congenital panhypopituitarism

Answer 5

rare, due to mutation of T.F genes= deficient in GH and at least 1 other hormone leads to short status and hypoplastic (small) anterior pit on MRI

Question 6

causes of acquired panhypopituitarism

Answer 6

tumours- hypothalamic (squashes pituitary) or pituitary (adenomas/cysts) radiation- causes pituitary damage, especially GH (not so much TSH) infection eg meningitis traumatic brain injury infiltrative disease (usually affecting pituitary stalk) inflammatory (autoimmune) pituitary apoplexy (due to haemorrhage) peripartum infection (sheehans syndrome)

Question 7

presentation of panhypopituitarism

Answer 7

symptoms due to deficient hormones: FSH/LH- secondary hypogonadism= low libido + secondary amenorrhoaea/erectile dysfunction ACTH- secondary hypoadrenalism= fatigue TSH- secondary hypothyroidism = fatigue

Question 8

sheehans sydrome cause

Answer 8

post partum hypopituitarism due to a post partum haemorrhage, which causes hypotension, and because anterior pituitary already enlarged during pregnancy due to more lactotrophs anyway, gland likely to die by infarcation

Question 9

presentation of sheehans syndrome

Answer 9

lethargy, anorexia and weight loss due to TSH/ACTH lactation (breastfeeding) deficiency due to low prolactin lack of periods post delivery (due to low FSH/LH) posterior not usually affected

Question 10

pituitary apoplexy

Answer 10

intra-pituitary haemorrhage (bleeding into the gland) /infarction, often due to patients already with pituitary adenomas anti-coagulants can cause this by increasing risk of bleeding

Question 11

presentation of pituitary apoplexia DIAGRAM

Answer 11

there is gap between optic chiasm and pituitary gland- in an adenoma there is no gap, so it can cause visual field defect (bitemporal hemianopia), as chiasm is squash MAIN presentation is severe sudden headache cavernous sinus has nerves and arteries, there, so adenoma can squash them and cause diplopia (double vision) and ptosis

Question 12

problem with biochemical diagnosis of hypopituitarism

Answer 12

measuring basal levels of hormones is limited as: cortisol changes throughout the day (high in the morning), T4 has a half life of 6 days, FSH/LH is cyclical, and GH/ACTH is pulsatile

Question 13

correct way of bichemical diagnosis

Answer 13

stimulated pituitary function tests- ACTH+GH are stress hormones that raise blood glucose, so an insulin induced hypoglycaemia causes GH and ACTH release TRH and GnRH also given to stimulate TSH/FSH+LH release

Question 14

radiological diagnosis of hypopituitarism DIAGRAM

Answer 14

MRI given to reveal haemorrhage, adenoma etc can see an EMPTY SELLA, with just a stalk and a thin rim of tissue

Question 15

deficient hormones, replacement and check

Answer 15

ACTH- hydrocortisone, check serum cortisol TSH- thyroxine, check serum T4 women LH/FSH- HRT, should cause withdrawal bleeds men LH/FSH- testosterone, serum testosterone GH- GH, check IGF1/growth chart in children

Question 16

growth hormone deficiency

Answer 16

children- causes short stature (2SDs below mean height, or abnormal growth on predicted percentile) adults- effects more complex

Question 17

causes of short stature

Answer 17

genetic (downs/turners/prader willi) syndrome emotional trauma systemic disease eg cystic fibrosis malnutrition and malabsorption (coelia) endocrine (cushings, hypothyrodism, GH deficiency) skeletal dysplasias (osteogenesis imperfecta/achondroplasia)

Question 18

causes of short stature in children

Answer 18

issue with hypothalamus- prader willi (less GHRH) issue with APG- pituitary dwarfism (low GH) issue with GH receptor on liver- laron dwarfism (low IGF1/2 from liver)

Question 19

detecting short statures in children

Answer 19

use growth charts and monitor height

Question 20

causes of acquired GH deficiency in adults

Answer 20

trauma pituitary tumour./surgery cranial radiotherapy

Question 21

diagnosis of GH deficiency

Answer 21

not random GH, give provactive challenge like insulin (if GH doesn’t reach 3mcg/L, deficient) GHRH+ arginine- tests whether GH can be made glucagon weirdly as well which would stimulate GH release exercise after tests, measure GH at specific time points before and after

Question 22

growth hormone therapy and benefits

Answer 22

prepare using human recombinant GH, and administer daily, adjusting dose to IGF-1 improved body composition with lower waist circumference, better lipid profile, better bone mineral density

Question 23

GH deficiency in adults presentation

Answer 23

lower lean mass, muscle, and increased fat, LDL and lower HDL

Question 24

risks of GH therapy

Answer 24

increased risk of cancer, although no data shows this expensive