Endo 7: Hypoadrenal Disorders Flashcards
(42 cards)
What does P450 enzyme do?
performs Side chain cleavage
how is cholesterol converted to cortisol + aldosterone ?
- start with cholesterol
- (in adrenal cortex) –> pregnenolone
- put OH group onto 17/21/11
–> forms cortisol
OR - if you put OH group onto 21/11/18 –> forms aldosterone
glucocorticoid synthesis enzymes + sex steroid synthesis enzymes = turned on by _____
glucocorticoid synthesis enzymes + sex steroid synthesis enzymes = turned on by ACTH
if pituitary detects stress –> _____ is produced
which turns on enzymes so you produce more ______
if pituitary detects stress –> ACTH is produced
which turns on enzymes so you produce more cortisol
how does cortisol production differ In the aldosterone pathway?
- renin + ATII turns on enzymes in the mineralocorticoid pathway –> to produced more cortisol
List common causes of adrenocortical failure
- Tuberculosis Addison’s Disease (Most common)
(TB grows in adrenal glands) - Autoimmune addison’s disease (most common in uk)
- congenital adrenal hyperplasia
(missing enzymes, lower level of cortisol –> so adrenal glands grow)
What happens in autoimmune addison’s disease?
- the immune system makes a mistake –> and wipes out the adrenal gland
What happens in congenital adrenal hyperplasia?
- can be complete/ partial
- caused by enzyme deficiency (commonly 21-hydroxylase deficiency) –> so adrenals can’t make hormones properly
- born with big adrenals
- adrenals can still make sex steroids due to overflow of 17 hydroxyprogesterone –> but can’t make anything else
- so cortisol + aldosterone = deficient
- testosterone = in excess (So if female, they would have abnormalities of the genitals)
List features/ symptoms of addison’s disease.
- pigmentation in mouth
- darker hair
- patches of vitiligo
- hypotension
- loss of weight
What are some consequences of adrenocortical failure?
- fall in BP
- loss of salt in urine
- increased plasma potassium
- fall in glucose due to glucorticoid deficiency
- high ACTH –> results in increased pigmentation (MSH)
Why does high ACTH result in increased pigmentation ?
POMC –> ACTH + MSH
- MSH = causes increase in pigmentation
POMC = broken down to:
POMC –> ACTH + MSH + endorphines + enkephalins + other peptides
how would you treat someone who is unconscious due to addison’s ?
inject hydrocortisone
What are some tests for addison’s
What would the results be like in a patient tie addison’s disease?
- cortisol at 9am
- test ACTH level
- short aynACTHen test
- cortisol at 9am = LOW e.g 100
- short aynACTHen test = LOW e.g 150
Describe the presentation of congenital adrenal hyperplasia
- hypotension
- virilisation (development of male physical characteristics in a female - AMBIGUOUS GENITALIA)
21 hydroxylase deficiency = recessive / dominant
21 hydroxylase deficiency = recessive
what is the difference between partial and complete 21- hydroxylase deficiency?
- same hormones will be low/high but not quite so severely.
- e.g low cortisol –> but only a little bit hypotensive
- long period of slightly raised testosterone
What happens in 11-beta hydroxylase deficiency ?
- you get build up of 11 deoxycorticosterone
- -> which is an active aldosterone receptor agonist
- so child is hypertensive, hypokalemic and virilised
What happens in 17-hydroxylase deficiency ?
- you get high levels of aldosterone
- so they are hypertensive + hypokalaemic
BUT - they are missing cortisol + sex steroids
–> so they never go through puberty - has borderline hypoglycemia
note: they don’t get addisonian crisis because they have aldosterone
Which hormones are deficient in 17-hydroxylase deficiency?
- cortisol + sex steroids
Which hormones are in excess in 17-hydroxylase deficiency?
- 11 deoxycorticosterone + aldosterone
What problems occur in 17 hydroxylase deficiency ?
- hypertension
- low K
- sex steroid deficiency
- glucocorticoid deficiency
(no cortisol, no sex steroids)
11-deoxycorticosterone behaves similarly to ________
in excess, it can cause ______ + ________
11-deoxycorticosterone behaves similarly to aldosterone
in excess, it can cause hypertension + hypokalemia
All steroids come from ________
cholesterol
