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striae and centropetal obesity
what is Cushing's syndrome?
excessive activation of GC receptors
what is cushing's disease?
- pituitary adenoma secreting ACTH
- leading to high cortisol
what is the most common cause of Cushing's syndrome?
exogenous steroid use
what is the commonest endogenous cause of Cushing's syndrome?
what are other causes?
- commonest endogenous cause - cushing's disease
- other - ectopic ACTH secretion/iatrogenic ACTH therapy
name two causes of ectopic endogenous ACTH secretion?
- bronchial carcinoid tumour
- small cell lung ca
name an endogenous cause of Cushing's syndrome that is ACTH independent?
which zones of the adrenal cortex produce what?
what receptors does NA work on and what are the effects?
alpha -> vasoconstriction
what receptors does adrenaline work on and what are the effects?
- alpha -> vasoconstriction
- beta -> vasodilatation, tachycardia, insulin receptors
what type of Cushing's syndrome are more common among:
- a) cushing's disease, cortisol secreting adrenal tumour
- b) ectopic ACTH small cell lung ca
sex ratio of cushing's disease?
4 women: 1 man
5 year mortality rate of Cushing's syndrome if untreated?
what are the three clinical differences between Cushing's syndrome and high cortisol caused by depression?
- proximal myopathy
NOT seen in depression
what can super-high cortisol levels do to potassium levels?
- cortisol's MC effect
test for Cushing's syndrome differentiation?
- dexamethasone suppression test:
- low dose doesn't decrease CORTISOL but high dose does -> cushing's disease
apart from the dexamethasone suppression test, what else can you use to test for Cushing's syndrome?
- insulin suppression
- CRH test
- check plasma ACTH levels
what is nelson's syndrome?
- pituitary macroadenoma that lacks negative feedback
- high ACTH
- brown skin
how do you treat nelson's syndrome?
what is mitotane? it may one day be used to treat cushing's
can you just take out an adrenal gland for cushings?
pred, dexamethasone, cortisone acetate, hydrocortisone are all what?
side effects of GC therapy?
- Cushing's syndrome
- DM due to insulin R
- peptic ulcers
- reactivation of latent TB
what must you be wary of when withdrawing GC therapy?
- prolonged use will reduce endogenous system
- so withdrawal needs to be tapered and monitored to avoid:
- low cortisol and androgens (MC are fine)
- -> n&v and shock
osteoporosis prophylaxis given with steroids?
- bisphosphonates eg alandronate
- calcium, vit D
- strontium ranelate
- PTH low dose
addison's causes low:
three consequences of low MC?
consequences of low GC?
- weight loss
- postural hypotension
management of an adrenal crisis?
- IV saline
- IV hydrocortisone succinate
- IV 10% glucose
- treat hyperkalaemia
treatment for hyperkalaemia (watch the heart!)?
- IV calcium gluconate
- inhaled salbutamol
- furosemide and fluids
diagnosis of adrenal insufficiency includes what?
- inadequate secretion of cortisol
- without or with low aldosterone too
CAN BE FATAL
what is Addison's disease?
- primary adrenal insufficiency
- high ACTH
causes of Addison's disease?
- waterhouse-friedrihsens syndrome
what is waterhouse-friedrichsen syndrome?
- intra adrenal bleed
- post meningoccal infection
causes addison's disease
non-addison's disease adrenal insufficiency?
- secondary adrenal insufficiency:
- low ACTH
2 causes of secondary adrenal insufficiency?
- GC withdrawal
- pituitary tumour
someone presents with fatigue, hyponatraemia and hypotension, what do you suspect?
what is the ACTH stimulation test used for testing adrenal insufficiency?
- give IM synacthen
- measure cortisol and ACTH in serum
what infections do you test for with adrenal insufficiency?
treatments in adrenal insufficiency:
androgens in women?
- GC - oral hydrocortisone
- MC - oral fludrocortison
- androgen - DHEA (given for decreased libido in women, men make androgens in testes so no need)
what percentage of adults have an adrenal incidentaloma?
how many are insignificant?
85% of them are insignificant
how can you test if an adrenal medulla mass is secreting NA/adr?
which of the following traits of an adrenal mass on CT is likely to make it a benign adenoma/incidentaloma:
small and smooth
when would you do a laparoscopic adrenalectomy for a benign mass?
- if it's >5cm
- if it's secreting stuff
common cause of primary hyperaldosteronism?
idiopathic bilateral adrenal hypertension
what is Conn's syndrome?
- rare cause of primary hyperaldosteronism:
- aldosterone producing adenoma
what are the symptoms of hyperaldosteronism?
- sodium retention -> HTN
- polyuria (nephrogenic DI)
- hypokalaemia due to K+loss
- metabolic alkalosis (H+ loss)
- tetany (metabolic alkalosis)
what does aldosterone do?
- PRINCIPLE CELLS:
- ENaC - increase sodium reabsorption
- ROMK - increase potassium excretion
- INTERCALATED CELLS:
- increase proton exrection
treatment for primary hyperaldosteronism?
- spironolactone/amiloride - MC antagonist
- laproscopic removal if Conn's (but HTN remains)
which one is chromaffin positive:
phaeo or paraganglioma?
what percentage of adrenal medulla tumours are paragangliomas?
- the rest are phaeochromocytomas
what percentage of people presenting with HTN are because of an adrenal medulla secretory tumour?
what percentage of phaeos are malignant?
what percentage of phaeos are inherited?
what tumour syndromes are phaeos linked to?
- von Hippel-lindau
- MEN II
which of the following assoc with mutations in succinate dehydrogenase B,C and D?
phaeo or paragangliomas?
clinical presentation of phaeo/paraganglioma?
- abdo pain
- glucose intolerance
why do people with a phaeo go through phases of hypotension?
because of the HTN causing episodes of pressure natriuresis
what does a serum chromogranin A result indicate?
- tumour marker:
- -a phaeo/paraganglioma met
- -or a non secretory phaeo in situ
what medication must someone with a phaeo take for 6 weeks before surgery?
phenoxybenzamide - alpha receptor blocker
NEVER just a beta receptor blocker!!!
what meds can you give during surgery for HTN?
- sodium nitroprusside
what do you do for phaeo with hepatic mets?
explain the genetics of congenital adrenal hyperplasia?
- autosomal recessive
- dodgey 21 hydroxylase enzyme
what are the following levels like in congenital adrenal hyperplasia:
a) aldosterone and cortisol
- a) low
- b) high because the precursor to a) and b) are the same and so it's all converted to this
- c) high, lack of negative feedback
what does the heel prick test for congenital adrenal hyperplasia test for in babies?
high levels of 17-hydroxyprogesterone
who gets pseudo-precocious puberty?
- kids with high ACTH
- due to congenital adrenal hyperplasia
why is there hypertension in congenital adrenal hyperplasia?
pre-cortisol enzyme buildup
treatment for CAH?
- replaces GC
- and this suppresses ACTH too so androgen levels come back down to normal
cortisol (and therefore ACTH too) release is diurnal - T/F?