adrenal disorders Flashcards
what is the core problem associated with cushing syndrome ?
excess cortisol
what is the most common cause of cushing ?w
corticosteroid medication
what is the difference between cushing disease and cushing syndrome ?
cushing disease is a pituitary disease
what is the cause of menstrual irregularities in cushing syndrome ?
cortisol alters the GnRH release
which in turn decreases FSH and LH
what are the broad causes of cushing syndrome ?
ACTH independent - glucocorticoid therapy , adrenal adenoma
ACTH dependent - cushing’s disease, ectopic ACTH secreting tumor
how is a diagnosis of cushing’s syndrome made ?
24 hour urine free cortisol levels
salivary cortisol
low dose dexamethasone suppression test
what is dexamethasone ?
a steroid
how is a dexamethasone suppression test done ?
1- a dose of dexamethasone is given before bed - in order to suppress ACTH release
2- morning blood test done
3- normally the cortisol levels should be low , but in cushing the cortisol levels will be high
after establish cushing syndrome what is the next best step to take ?
measure ACTH levels
what is the high dose dexamethasone test ?
differentiates the cause of the high ACTH cushing syndrome
if the cause is due to pituitary adenoma - there will be a decrease in cortisol
if the cause is an ACTH secreting tumor - the cortisol will not decline
what is the treatment for cushings sundrome ?
remove the source
use ketaconazole
what is the function of ketoconazole ?
inhibits desmolase , the first step needed for the formation of cortisol
what are the key side effects associated with ketoconazole ?
gynecomastia
what is adrenal insufficiency and what are the two types ?
when there isn’t enough cortisol is made
1- primary adrenal insufficiency - Addison’s disease , cortisol and aldosterone are low , ACTH is high
2- secondary adrenal insufficiency - failure of pituitary release of ACTH - no stimulus for the release of cortisol , only cortisol is low
what are the symptoms of adrenal insufficiency ?
postural hypotension
hypoglycemia
hyperkalemia
acidosis
hypovolemia
what is the classic scenario associated with Addison’s hyper pigmentation ?
GI symptoms
darkening of the skin
what is adrenal crisis ?
abrupt loss of cortisol and aldosterone
main manifestation is shock
when does an adrenal crisis occur ?
patients who are already on long term glucocorticoid therapy and then undergo stress - surgery or infection
a sudden need for cortisol is needed
how is adrenal crisis prevented?
stress dose steroids
what are the cause of Addison disease ?
autoimmune - antibodies to the 21 hydroxylase enzyme
infections - TB , fungal CMV
what is the waterhouse friderichsen syndrome and what is the cause?
rare cause of acute adrenal insufficiency
caused by hemorrhage in the adrenal glands
what is waterhouse - friderichsen usually associated with ?
meningococcemia
non blanching rash
what is the classic case associated with waterhouse friderichsen ?
patient with bacterial meningitis
acute onset of shock
what is the most common cause of secondary adrenal insufficiency ?
glucocorticoid therapy due to chronic suppression of ACTH release
leads to adrenal atrophy
sudden discontinuation - hypoadrenalism
what can help differentiate 1ry from 2ry adrenal insufficiency clinically ?
there is no skin hyper-pigmentation in 2ry (ACTH is low)
no hyperkalemia - aldosterone is not affected
what are the diagnostic tests for adrenal insufficiency ?
8 AM serum cortisol - levels should be high
Serum ACTH - low levels suggest 2ry adrenal insufficiency
ACTH stimulation test
what are the different results of ACTH stimulation test and what do they indicate ?
exogenous ACTH is given
failure to rise - primary adrenal insufficiency
normal rise - secondary disorder
what are the most common causes of primary aldosteronism ?
bilateral idiopathic aldosteronism
aldosterone producing adenoma ( conns syndrome)
how is a diagnosis of primary aldosteronism made ?
plasma renin activity
plasma aldosterone conc
how are the results from measuring the plasma renin activity evaluated ?
low PRA and high PAC - 1ry aldosteronism
high PRA and high PAC - 2ry aldosteronism
what are the common causes of 2ry aldosteronism ?
renal artery stenosis
CHF
Low volume
what are the treatment options for 1ry aldosteronism ?
surgical adrenalectomy
spironolactone
what are phaeochromocytomas ?
catecholamine secreting tumors
affection of chromaffin cells of the adrenal medulla
what is the clinical presentation of pheochromocytoma ?
classically episodic symptoms
paroxysmal headaches hypertension
headaches
how is a diagnosis of pohechromocytoma made ?
24 hour urine collection of metanephrines
what is the definitive treatment for pheochromocytoma ?
surgery
phenoxybenzamine ( alpha blockade)
non selective beta blocker
alpha blockade must come first
what is a neuroblastoma ?
derived from neural crest cells
tumor of sympathetic ganglion cells
what gene mutation is associated with neuroblastoma and what age group is associated ?
n-myc gene
almost always in children
what is the presentation of neuroblastoma ?
usually present with abdominal pain in children
opsoclonus myoclonus ataxia - dancing eyes
violaceous eyelids
how is a diagnosis of neuroblastoma made ?
urinary HVA VMA levels
what is the prognosis of neuroblastoma ?
the younger the patient the better
children over 18 usually die
amplification of n myc - poor prognosis
what imaging is used for the diagnosisi of phaeochromocytoma and neuroblastoma ?
MIBG
what precautions must be taken in MIGB scan ?
thyroid must be protected
give potassium iodidie
what are the most important features for cushingoid appearance ?
purple striae on the abdomen
osteoporosis ( compression fracture of the vertebrae)
avascular necrosis of the femoral head
what is the presentation of cushing in children ?
precocious puberty
what is the classic case associated with adrenal crisis and what is the appropriate treatment ?
patient who has an autoimmune disease that is being treated with prednisolone
goes into surgery - high BP drop
give IV hydrocortisone
what is the presentation of familial hyperaldosteronism ?
increased aldosterone levels
increased sodium and water retention
no mention of renin
family history
