Adrenals Flashcards
(35 cards)
What do the adrenals secrete
steroid molecules; stimulated by ACTH from pituitary
-aldosterone controlled by angiotensin
What is the backbone of all major steroids
cholesterol
What are the effects of the adrenal hormones
regulate metabolism
cardiovascular function
growth
immunity
Synthesis and secretion of the adrenal hormones is regulated by
CNS- sensitive to negative feedback by circulating cortisol and exogenous synthetic glucocorticoids
What is the HPA axis
Hypothalamus sends signal to Pituitary
Pituitary to adrenals
adrenals with negative feedback to pituitary and hypothalamus
How is Cortisol (hydrocortisone) secreted
in a circadian rhythm, pulsatile
peak in early AM and after meals (esp lunch)
What is CBG (cortisol binding globulin)
made in liver, binds 90% of cortisol normally
increases in pregnancy, estrogen administration, and hyperthyroid
decreases in hypothyroid, protein deficiency, and genetic defects
*Synthetic steroids (DXM) bind to albumin, not CBG
Vascular and smooth muscle respond to
catecholamines; response is lower without cortisol
Glucocorticoid actions are most apparent when
in the fasting state- they contribute to maintaining adequate glucose supply to the brain
Some functions of cortisol include
gluconeogenesis
release AA from muscle catabolism
inhibit peripheral glucose uptake
stimulate lipolysis
What are the pharmacokinetics of cortisol
half life 60-90 minutes
increased if stressed, hypothyroid, or with liver dz
metabolized in liver
excreted in urine
What are the diseases of the adrenal cortex
acute adrenocortical insufficiency (adrenal crisis)
chronic adrenocorticol insufficiency (addison’s dz)
hypercortisolism (cushing’s syndrome)
hyperaldosteronism
What is an adrenal crisis
insufficient cortisol causing weakness, abdominal pain, fever, confusion, N/V/D, Low BP- increased skin pigment
MC een in primary adrenal insufficiency, not pituitary d/o
How can you test for adrenal crisis
Cosynotropin (synthetic ACTH) Stimulation test
normal response: increase serum cortisol 20mcg+
How do you treat acute adrenal insufficiency
Hydrocortisone 100-300mg
Fludrocortisone acetate PO (mineralocorticoid to reduce edema)
What steroids are preferred
- Hydrocortisone
- Prednisone
-Fludrocortisone ONLY for BP management
Rarely used is dexamethasone
*Topicals have no effect on adrenal insufficiency
What is an important ADE of fludrocortisone
salt and fluid retention (CHF)
What is Addison’s disease
primary adrenal insufficiency 2/2 dysfunction or absence of the adrenal cortices
Symptoms of Addison’s disease include
Akin pigmentation hypotension, small heart hyponatremia hyperkalemia, hypercalcemia high BUN weakness, anorexia, weight loss, amenorrhea high ACTH, low cortisol
How do you treat Addison’s disease
Corticosteroids (alone if mild) or + Mineralocorticoids (fludrocortisone) with aggressive IV saline and glucose
- *Hydrocortisone 2/3 in AM, 1/3 in late afternoon (alternate is prednisone)
- Fludrocortisone acetate (sodium retention)
How does dosing change
Increase if with: postural hypotension, hyponatremia, hyperkalemia, or fatigue
Decrease if: edema, hypokalemia, hypertension
Why do some with Addison’s disease take DHEA
provides improved sense of well being
increased muscle mass
reversal of bone loss at femoral neck
*monitor older women for androgen effects
If someone with Addison’s has an episode, how do you treat
minor stress glucocorticoid coverage: 2x replacement of hydrocortisone over 24 hrs
major stress glucocorticoid coverage: 10x replacement of hydrocortisone over 48 hrs
How does prednisone work
activates glucocorticoid receptor and alters gene transcription
