Patho - adrenal gland Flashcards
adrenal medulla secretes:
- epinephrine
- norepinephrine
adrenal cortex secretes:
- mineralocorticoids
- glucocorticoids
where is the short term stress response from?
- adrenal medulla
- epi and norepi
short term stress response
- increase in blood glucose
- increased BP
- increased breathing rate
where is the long term stress response from?
- adrenal cortex
- mineral and glucocorticoids
long-term stress response effects of mineralocorticoids
- retention of Na and water by kidneys
- increased blood volume and BP
long-term stress response effects of glucocorticoids
- increased blood glucose
- immune system suppression
adrenal cortex: steroid hormone production
-flow from cholesterol to aldosterone
cholesterol –> progesterone – (21-hydroxylase) –> corticosterone –> aldosterone
all end points of cholesterol from the adrenal cortex
- aldosterone
- cortisol
- estradiol
- DHT
*review this whole chart, he said to know it
adrenal cortex
- 3 zones
- corticosteroid hormones are synthesized from cholesterol by cytochrom P450 enzymes
zona glomerulosa
aldosterone causes K wasting and Na reabsorption in the distal nephron of the kidney
zona fasciculata
- cortisol production under influence of ACTH from the pituitary
- circadian rhythm: high levels in morning and very little secreted at night
zona retiucularis
- adrenal androgens are synthesized
- DHEA and SHEAS
- under the influence of ACTH
what is the key in the steps that occur in the adrenal medulla?
tyrosine metabolism
an increase of production of adrenal medulla catecholamines causes what?
pheochromocytoma
underproduction of adrenal medulla catacholamines causes what?
-not many problems like an increase does b/c there are plenty of catecholamines produced by the SNS
adrenal hormone excess =
cushing’s
MC cause of Cushings
- taking exogenous steroids w/ glucocorticoid activity
- 5 mg/day of prednisone is unlikely to cause suppression but higher doses for 3 weeks or more can
difference b/w cushing’s disease and cushing’s syndrome
- disease: overproduction of ACTH from the pituitary gland which stimulates the adrenal cortex to make corticosteroid
- syndrome: excess from any other source (exogenous steroids)
physical findings of cushing’s
- centripetal obesity
- facial plethora
- supraclavicular fat pads
- wide violaceous striae
- buffalo hump
a physical finding differentiation between cushing disease and syndrome
hyperpigmentation usually means it’s coming from the pituitary (cushing’s DISEASE)
ACTH dependent vs. independent Cushing’s syndrome
- dependent: (aka disease) caused by pituitary adenoma; 2/3 of cases
- independent: caused by hyperplasia of the adrenal gland or adrenal adenoma
w/u of cushing’s
- clinically suspected
- exclude exogenous glucocorticoids
- initial testing: 24 hr. UFC; LN salivary cortisol
- if nl, Cushing is unlikely
- if abnl: exclude physiologic hypercortisolism - if physiologic is excluded, do additional testing
important note on diagnostic testing of the pitutary/adrenal glands
- biochemical testing first!!
- b/c there are common findings of non-functioning adenomas in both glands
initial cushings testing
- low dose dexamethasone suppression test
- 24-hr urine free cortisol
- late night salivary cortisol
steps to take after cushing’s has been established
- further testing to determine if it’s ACTH dependent or independent
- referral to endo
tx for CS if caused by pituitary tumor
surgery
tx for CS if caused by adrenal adenoma
surgery
tx of CS if caused by hyperplasia
-refer to endo
adrenal insufficiency
- may be d/t failure of the adrenal glands (primary)
- or maybe inadequate secretion of cortisol form adrenals d/t other causes: critical illness (story of little baby)
- or pituitary ACTH deficiency (secondary)
sx of cortisol deficiency
- fatigue
- weakness
- low grade fever
- weight loss
- anorexia
- n/v
- abdominal pain
- arthralgia
- myalgia
signs of cortisol deficiency
- hyperpigmentation
- decrease in BP
lab finding of cortisol deficiency
- decreased serum cortisol
- increased ACTH
- decreased Na and glucose
sx of aldosterone deficiency
- salt craving
- dizziness
signs of aldosterone deficiency
- orthostasis
- hypotension
lab findings of aldosterone deficiency
- increased PRA
- increased K
- decreased Na
S/S of DHEAS deficiency
-reduced libido
-decreased axillary or pubic hair
(in women only)
MC cause of primary adrenal failure
autoimmune adrenalitis
-antibodies to 21-hydroxylase
diagnosis of primary adrenal failure
- based on low serum cortisol levels
- most will present w/ hypotension, hyponatremia, hyperkalemia
lab cortisol values in primary adrenal failure
- early morning cortisol of <3ug/dl consistent w/ cortisol deficiency
- > 15 excludes this diagnosis
what to do if cortisol testing = 5-14 ug/dl
stimulation testing w/ synthetic ACTH
how to differentiate primary vs secondary adrenal insufficiency
measure 8am plasma ACTH
potential effects of primary adrenal insufficiency
Fatal!! this is why you have to pay attention of mineralocorticoid and glucocorticoid effect and strength of drugs
steroid drug strengths
- hydrocortisone: 1
- prednisone: 4
- prednisolone: 4
- methylprednisolone: 5
- triamcinolone: 5
- dexamethasone: 25
- bethamethasone: 25
- cortivazol: 50
adrenal crisis
- adrenal fxn during critical illness:
- pts who have been on cortisol replacement tx may need emergent dose of hydrocortisone when they become ill
- pts who have been on steroids daily (COPD, arthitis, etc) will need a stress dose when acutely ill b/c they pituitary is suppressed
primary aldosteronism
- autonomous secretion of aldosterone
- usually adrenal adenoma
- in 10% of pts w/ HTN
how do pts w/ primary aldosteronism usually present?
with hypokalemia and metabolic alkalosis
what to do when primary aldosteronism has been established
- CT to determine if there is an adenoma, hyperplasia, or carcinoma
- renal vein renin then localize the source
tx of primary aldosteronism
- mineralocorticoid antagonsits (spironolactone)
- surgery
pheochromocytom
- tumor of the adrenal medulla secreting catecholamines (epi, norepi, dopamine)
- most cause intermittent or sustained HTN
- 1/3 occur w/ MEN-2
best screening test for pheo
plasma free metanephrine
