Flashcards in Disorders of Adrenal Gland Deck (41)
what are corticosteroids derived from?
what is aldosterone regulated by?
renin-angiotensin system and plasma potassium
describe the renin-angiotensin system?
when blood pressure fall, kidneys release renin.
renin converts angiotensinogen into angiotensin 1
ACE then converts angiotensin 1 into angiotensin 2
angiotensin 2 causes BP to increase
angiotensin 2 also causes adrenals to release aldosterone which causes salt retention and also increase BP
what are the main clinical actions of corticosteroids
metabolic effects of cortisol
increase blood glucose
circulatory effects of cortisol
increase cardiac output
increase renal flow
CNS effects of cortisol
bone/connect tissue effects of cortisol
decrease collagen formation
decrease wound healing
decrease serum calcium
most common cause of primary adrenal insufficiency
autoimmune destruction of adrenal cortex
anorexia , weight loss
what can cause primary adrenal insufficiency?
congenital adrenal hyperplasia
best test to diagnose Addison's?
short Synacthen test (ACTH levels will be high)
hydrocortisone and fludrocortisone
what does the hydrocortisone replace in addisons?
what does the fludrocortisone replace in addisons?
in addisons what will the levels of renin and aldosterone be like?
in addisons what will Na and K be like?
what causes secondary adrenal insufficiency?
lack of CRH or ACTH
what is the most common cause of secondary adrenal insufficiency?
exogenous steroid use
(high dose prednisolone, inhaled corticosteroid etc)
what is clinically different between primary and secondary adrenal insufficiency?
primary -tanned skin
secondary-pale skin as no increase in ACTH
increase risk infection
what are the ACTH dependent causes of cushings
what are the ACTH independent causes of cushings
definitive test for cushings
low dose dexamethsone suppression test
what is the most common cause of cortisol excess?
Iatrogenic cause- due to prolonged high does steroid therapy
this causes chronic suppression of pituitary ACTH production and adrenal atrophy
what is conn's syndrome?
what the sub types of primary aldosteronism?
adrenal adenoma (conns)
bilateral adrenal hyperplasia (most common)
how do diagnose primary aldosteronism?
1. confirm aldosterone excess-do aldosteronee/renin ratio
2. confirm subtype- adrenal CT
how do you treat adrenal adenoma?
how do you treat bilateral adrenal hyperplasia?
MR antagonists- spironolactone
what is the most common congenital adrenal hyperplasia?
21 alpha hydroxylase deficiency
how do you diagnose 21 alpha hydroxylase deficiency?
basal or stimulated 17-OH progesterone
clues for phaeochromocytoma?
paroxysmal sweating, headache
the classic triad:
biochem abnormalities for phaeochromocytoma?
may have low K+
the 10% tumour
10% extra adrenal
10% associated hyperglycaemia
10% in children
10% familial (more like 25%)
diagnosis of phaeochromocytoma
confirm catecholamine excess- urine/ plasma
identify source- MRI abdo, whole body, PET scan
treatment for phaeochromocytoma
full alpha and beta blockade
fluid and or blood replacement
surgery-total excision where possible
chemo if malignant