adrenal failure Flashcards
what are the 3 types of corticosteroids made in the adrenal cortex
mineralcorticoids - aldosterone
glucocorticoids - cortisol
sex steroids - androgens,oestrogens
what is the precursor for corticosteroids
cholesterol
what is the effect of angiotensin 2 on adrenals
activatiob of side cleavage of: 3 hydroxysteroid degydrogenase 21 hydroxylase 11 hydroxylase 18 hyroxylase
what is the action of aldosterone
controls bp
maintains sodium
lowers potassium
what effect does angiotensin 2 have on cholesterol
helps synthesise aldosterone
effects of acth on adrenals
activation of following enzyme side chain cleavage: 3 hydroxysteroid dehydrogenase 21 hydroxylase 11 hydroxylase 17 hydroxylase
where is cortisol produced
zona fasiculata
where is aldosterone produced
zona glomerulosa
what is addisons disease
primary adrenal failure
adrenal gland has hypetrophied or destroyed by tb
or autoimmune - immune system destroys adrenal cortex
what are some signs and symptoms of adrenal failure
hyperpigmentation and vitaligo low bp (postural hypotension) weakness weight loss nausea, diarrhea, constipation abdominal pain
why do we see hyperpigmentation in addisons disease
pituitary starts secreting a lot of acth hence msh
precursor is pomc
what are the signs of adrenal crisis
fever, syncope, convulsions, hypoglycaemia, hyponatraemia, severe vomitting and diarrhea
what are the causes of adrenocorticol failure
addisons - destruction and autoimmune
enzymes in steroid synthesis pathway not working - congenital adrenal hyperplasia
consequences of adrenocortical failure
fall in bp loss of salt in urine increased plasma potassium fall in glucose due to glucocorticoid def pigmentation eventual death due to low bp
test for addisons
after suspicion 9am cortisol - low acth - high short synAcTHhen test - 250ug measure cortisol response
how would you treat a patient with addisons disease
replacement aldosterone - fludrocortisone - longer half lifes and effects seen for longer
50-100mcg given daily
this is to increase bp
how would you treat cortisol deficiency
give hydrocortisone 3 times
10,5,2.5
what is the longer lasting version of hydrocortisone
prednisolone - longer half life and lasts longer
3mg daily
what is congenital adrenal hyperplasia
enxymes missing/ partial
commonest is 21 hydroxylase def
CAH - age of presentation
complete 21 hydroxylase deficiency
neonate - salt losing addisonian crisis
in utero - gets steroids across plaenta
girls could have ambiguous genitalia - virulisation
what can partial 21 hydroxylase deficiency cause
main problem in later life - hirsutism and viriisation in girls
precocious pubery in boys due to testosterone
acne
small breasts
what does 11 hydroxylase deficiency cause and why
11 deoxycorticoserone behaves like aldosterone
can cause hypertension and hypokalaemia
problems with 11 hydroxylase def
virilisation
hypertension
hypokalaemia
what problems can 17 hydroxylase cause
no sex steroids and cortisol
high bp
low k
