Hypoadrenal disorders Flashcards
What is the precursor of all adrenal steroids?
Cholesterol
What is the most common cause of adrenocortical failure and how does it differ in developed and developing world?
Born with normal adrenal glands but they were destroyed:
Developing - TB
Developed - autoimmune
What is a less common cause of adrenocortical failure?
Enzymes in steroid synthetic pathway not working - congenital adrenal hyperplasia
What are examples of autoimmune disorders in the endocrine system?
Primary hypothyroidism
Graves disease
Type 1 diabetes
Hypophysitis
What are signs and symptoms of adrenocortical failure?
Postural hypotension Vitiligo Skin Pigmentation - buckle and in scars Really tiredness Loss of weight Muscular dystrophy
What does the adrenal gland look like in different causes of adrenocortical failure?
Atrophied in autoimmune
Granulomas in TB
Other cancers can metastisise to the adrenals and stop them working
What are consequences of adrenocortical failure?
Fall in BP Loss of salt in urine Increase plasma K Fall in glucose due to glucocorticoid deficiency High ACTH increasing pigmentation Eventual death due to severe hypotension
Why does glucose fall in adrenocortical failure?
No cortisol and cortisol is used to mobilise glucose
Why does adrenocortical failure cause pigmentation?
Body increases ACTH to try kickstart the formation of aldosterone but no adrenal glands to make this but ACTH goes up and up and the precursor to ACTH is POMC which breaks down into MSH (melanocyte maker) and ACTH
Where is POMC synthesised?
In pituitary
What is POMC broken down into?
ACTH MSH Endorphins Enkephalins Other peptides
Test for Addisons?
Normally 9am cortisol is high, if it is low at 9am and ACTH is high then it is a sign
Give a short synACTHen test - give 250 ug synacthen IM and measure cortisol response. If cortisol doesn’t rise a huge amount- confirms Addisons
What is the commonest cause of congenital adrenal hyperplasia?
21 hydroxylase deficiency
Which can be complete or partial
What hormones will be deficient in 21 hydroxylase deficiency?
progesterone -> 11 deoxycorticosterone -> aldosterone
17 OH prog -> 11 deoxycortisol -> cortisol
How long can you survive with 21 hydroxylase deficiency?
Less than a few weeks
What hormone will be in excess in 21 hydroxylase deficiency?
Sex steroids - particularly testosterone
Why is the excess steroid in 21 hydroxylase deficiency bad?
Virilised - Too much androgen in utero so might need to karyotype baby to make sure is female baby or male because the female babies will look like male (enlarged clitoris or penis)
Why do partial 21 hydroxylase deficiency patients normally turn up to clinics later in life?
Normally had enough cortisol and aldosterone to keep them out of trouble - women has hirsutism or male with early/accelerated puberty
Problems that occur in 17 hydroxylase deficiency
Hypertension
Low K
Sex steroid deficiency
Glucocorticoid deficiency
What can 11 hydroxylase deficiency cause?
It is a mineralocorticoid and behaves like aldosterone so sodium and water in potassium out, hypertension and hypokalaemiaa
What are problems that can occur in 11 hydroxylase deficiency?
Virilisation
Hypertension
Hypokalaemia
