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Flashcards in Adrenal II Deck (16):

effects of catecholamines on alpha receptors

vasoconstriction, pupil dilation, intestinal relaxation, sphincter contraction, pilomotor contraction, bladder sphincter contraction


effects of catecholamines on beta receptors

vasodilation, cardioacceleration, cardiac inotropy, uterine relaxation, bronchodilation, glycogenolysis, lipolysis, bladder relaxation


symptoms of adrenal insufficiency

weakness and fatigue, loss of appetite, GI symptoms (nausea, vomiting, abdominal pain, diarrhea).
minor symptoms include salt craving, postural dizziness, muscle and joint pain


signs of adrenal insufficiency; mechanisms of these signs

weight loss, incr. skin pigment (incr- melanocyte stimulating hormone and ACTH share a precursor molecule, POMC. in primary insufficiency, there is high ACTH and therefore high MSH), low BP, vitiligo (related to autoimmune hypothyroidism- both of these are usually autoimmune problems).


Lab findings in adrenal insufficiency and reasons for them

low Na, high K, low blood sugar (in kids more than adults)
sodium: aldo causes sodium retention. without it, you have sodium and water wasting. ADH will go up to prevent hypovolemia, which further dilutes sodium
K: no aldo, so less K secretion in distal nephron
sugar: if it happens, it is due to a loss of cortsol effects on hepatic glucose storage and output


Dx of adrenal insufficency

low cortisol is the hall mark
low cortisol is normal at some times during the day
early morning cortisol < 5 mgm/dl suggests adrenal insufficiency; >15 makes it unlikely
testing response to synthetic ACTH is the benchmark for diagnosis- if there isn't a rise after a dose of ACTH, you can infer an adrenal defect
normal response is to 250 mcg rise


causes of primary adrenal insufficiency

1. inherited disorders of adrenal steroidogenesis:: 21 hydroxylase deficiency is the most common and causes congenital adrenal hyperplasia
other reasons possible but I'm not going to memorize them
2. autoimmunity
3. adrenoleukodystrophy
4. congenital adrenal hypoplasia
5. acquired disorders: adrenal hemorrhage, infectious adrenalitis (TB or fungi, AIDS)


What happens in CYP21 hydroxylase deficiency: pathophysiology

cause of congenital adrenal hyperplasia
no ability to make aldo or cortisol
adrenals only make sex hormones

high levels of 170hydroxyprogesterone because there is backup of 21 hydroxylase substrates
adrenal hyperplasia because the brain knows it needs more cortisol and there are very high levels of ACTH


CYP21 hydroxylase deficiency: signs and symptoms

babies have cortisol deficiency and salt wasting. they become very very dangerously hypotensive within a few days-wks after birth
girls have ambiguous genitalia in severe forms
others may have virulization, precocious puberty. may be so mild that it presents similar to PCOS
males can get adrenal rests on the testes (tumors)


Tx of 21 hydroxylase deficiency

prevents adrenal crisis
lowers androgens in women
prevents adrenal rests on testes


What is another cause of congenital adrenal hyperplasia (not 21-hydroxylase deficiency)

3 beta HSD deficiency.
looks just like 21 hydroxylase deficiency but DHEA is INCREDIBLY high (even higher than in 21 hydroxylase deficiency, since there isn't any androstenedione) and the 17-OH progesterone is low


autoimmunity and primary adrenal insufficiency

look for antibodies against cyp 21
think about auto immune polyglandular syndrome


How does adrenoleukodystrophy result in primary adrenal insufficiency?

adrenoleukodystrophy is a defect in fatty acid oxidation that causes an accumulation of very long chain fatty acids in the blood
can disrupt adrenal function


Causes of adrenal hemorrhage

anticoagulation, antiphospholipid antibody syndrome, sepsis,


treatment of adrenal insufficiency

acutely, replace intravascular volume and replace glucocorticoids at higher stress levels
chronically, replace glucocorticoids at physiologic levels, replace mineralocorticoids as needed, and adjust glucocorticoid levels up when stress occurs. encourage use of a medical alert bracelet


Causes of "secondary" adrenal insufficiency (problems that aren't due to intrisic renal disease). Distinctive features of secondary adrenal insufficiency

most commonly, pharm dose glucocorticoids
or, defects at pituitary level
features: no hyperpigmentation (you don't have high ACTH/MSH levels), normal aldo secretion (aldo is caused promoted by the renin-angiotensin system, which is independent of ACTH)