Adrenal insufficiency Flashcards
definition: adrenal insufficiency
clinical manifestations of deficiency of hydrocortisone, the primary glucocorticoid
definition: primary AI
- destruction of the adrenal glands
- deficiencies of corticosteroids, mineralocorticoids and adrenal androgens
definition: secondary AI
- damage to hypothalamus or pituitary (deficiency in CRH or ACTH)
- deficiency of corticosteroids only
why are deficiencies in catecholamines and adrenal androgens spared in primary AI?
- there are extra-adrenal sites of catecholamine production
- adrenal androgen deficiency is not a problem as majority of androgens are made in testes and ovaries
why is aldosterone production unaffected by secondary adrenal insufficiency?
it is not regulated by the HPA
why is there no clinical syndrome of adrenal medulla insufficiency?
extra adrenal sites of catecholamine production - paragangliomas
what are the main sites of aldosterone action?
- distal convoluted tubules
- collecting ducts
what are the roles of aldosterone?
- conserve sodium
- eliminate potassium
functions of angiotensin II
- increase release of aldosterone from adrenal cortex
- increase renal sodium retention
- increase vasoconstriction
- increase release of ADH from posterior pituitary
- stimulates brain thirst center
- facilitates NE release from sympathetic nerve endings
- stimulates cardiac hypertrophy
primary AI: which hormones are deficient?
all 3:
- glucocorticoids
- mineralocorticoids
- adrenal androgens
primary AI: lab findings (cortisol, ACTH, aldosterone, renin, DHEA)
- low cortisol
- high ACTH
- low aldosterone
- high renin
- low DHEA
primary AI: treatment
- fludricortisone
- hydrocortisone
- prednisone
what are the two main etiologies of primary AI?
- autoimmune destruction
- TB
what signs are unique to primary AI?
hyperpigmentation
hyperkalemia
what explains the hyperkalemia in primary AI?
- aldosterone deficiency
- increased renin
- hyponatremia and salt craving
