congenital adrenal hyperplasia Flashcards
what is the level of cortisol in association with CAH and what effect does this have ?
always low cortisol
which drives up the levels of ACTH
which results in the production of other hormones ( androgens or aldosterone)
what is the difference in presentation between aldosterone excess vs deficiency ?
deficiency - sodium loss , water loss
hypovolemia - shock , hyperkalemia
excess - sodium retention , hypokalemia , renin is low
what is the presentation of a child with excess androgen vs androgen defeciency ?
excess - in females, ambiguous genital
males - early puberty
deficiency - females - appear normal
males - female or ambiguous genitalia
what are the effects of high levels of ACTh ?
can cause darkening of the skin due to the stimulation of MSH , increasing levels of melanin synthesis
why does an increase in ACTh levels have an effect on MSH levels ?
they have the same precursor POMC
what is the most common cause of CAH ?
21 alpha hydroxylase
what is the result of a deficiency of 21 alpha hydroxylase ?
no cortisol made
no aldosterone made
only androgen can be made
if no cortisol is made this means ACTH levels increase
what is the presentation of 21 alpha hydroxylase ?
increase serum potassium
low sodium
low ph
low hco3
low glucose
what is the effect of 11 beta hydroxylase deficiency ?
1- there is no cortisol production - hence the increase in ACTh
2- no aldosterone production but the precursor is made - causing an accumulation of it
3- excess androgen production
what is the main distinction between 21 hydroxylase and 11 beta hydroxylase deficiency ?
there is an increase in mineralocorticoid activity in 11 beta hydroxylase
which presents as hypokalemia and hypertension
what is the effect of 17 alpha hydroxylase deficiency ?
there is a deficiency in cortisol production - so high ACTH
deficiency in androgen production
but intact aldosterone production
what is the distinction between 17 alpha deficiency and the rest ?
low androgen levels
what is the presentation of 17 alpha hydroxylase in males ?
in a male - complete female genitalia or mabigious
undescended testes
what is the presentation of 17 alpha hydroxylase defeciency in females ?
normal at birth
primary amenorrhea at puberty
diagnosed at puberty
what are the features of 3 beta hydroxysteroid dehydrogenase deficiency ?
mafeesh 7aga 5ales btt3mel
what is the next best step when a child is presenting with amibious genitalia ?
check if XX or XY
XX- excess androgen , often CAH
XY - lack of androgens , rarley due to CAH
how is screening of CAH made ?
measure levels of 17 - hydroxyprogesterone
what is the treatment for CAH ?
glucocorticoids
what is the mechanism responsible for adrenal hyperplasia in CAH ?
the lack of cortisol production increases the levels of ACTH
increased ACTh causes the hyperplasia
what substrates are increased in 21 and 11 hydroxylase defeciency ?
17 OH
DHEA
