ADRENAL INSUFFICIENCY Flashcards
where are the adrenal glands located?
they sit at the superior poles of the kidneys
what do the adrenal glands consist of?
- adrenal medulla
- adrenal cortex
what is the adrenal medulla, and what does it secrete?
its the inner portion of the adrenal gland
responds to sympathetic stimulation by secreting catecholamines (epinephrine and norepinephrine)
what does the adrenal cortex consist of?
its the thick outer portion
consists of 3 layers
1. zona glomerulosa (outer)
2. zona fasciculata (middle)
3. zona reticularis (inner)
what does the adrenal cortex do?
synthesizes 25 steroid hormones that are collectively known as corticosteroids
what are mineralcorticoids secreted by?
zona glomerulosaw
what do mineralcorticoids control?
electrolyte balance by acting on the kidneys
what is the main mineralcorticoid?
aldosterone
what are glucocorticoids secreted by?
zona fasciculata
what is the main glucocorticoid?
cortisol
what do glucocorticoids do?
- stimulate fat and protein catabolism
- gluconeogenesis (the synthesis of glucose from non-carbohydrate sources) in the liver
- release of fatty acids and glucose into the blood
- help the body adapt to stress
what is aldosterone?
part of a hormone family with renin and angiotensin
why is aldosterone secreted?
its secreted directly in response to hyperkalemia and via the RAA system in response to low blood volume/low blood pressure
what is adrenal insufficiency?
inadequate production of adrenocortical hormones -> glucocorticoids (cortisol), mineralcorticoids (aldosterone), and adrenal androgens
what are the types of adrenal insufficiency?
- primary
- secondary
- tertiary
what is primary adrenal insufficiency?
addison’s disease
dysfunction or destruction of the adrenal cortex
what is secondary adrenal insufficiency?
conditions that cause deficiency in pituitary ACTH secretion
MOST COMMON FORM
what is tertiary adrenal insufficiency?
conditions that cause deficiency in the hypothalamic secretion of CRH
is addisons disease autoimmune?
yes
what is the most common cause of adrenal insufficiency (70% of cases are this)?
autoimmune
(addison’s)
what happens in autoimmune (primary disease) of adrenal insufficiency?
adrenal cortex is gradually destroyed leading to loss of mineralcorticoids, glucocorticoids, and adrenal androgen hormone production
minus the autoimmune aspect what is the second most common cause of primary adrenal insufficiency?
infection! TB
hemorrhage is another cause of primary adrenal insufficiency. what does this mean?
it is the rupture of the adrenal cortex blood vessels d/t increased BP leading to tissue ischemia
what type of adrenal insufficiency is metastatic cancer a cause of?
primary!
what is the cause of secondary adrenal insufficiency disease?
hypopituitarism causing a decrease in ACTH
- pituitary tumors and surgery
what is the cause of tertiary adrenal insufficiency disease?
- prolonged high-dose glucocorticoid use suppresses the HPA axis
- effects of cushings syndrome tx
what does the hypothalamus secrete in the HPA axis?
CRH
what happens after the hypothalamus secretes CRH in the HPA axis?
ACTH is released from the anterior pituitary gland
what is the zona glomerulosa primarily regulated by and why?
RAA and potassium levels
because the zona glomerulosa secretes aldosterone
when does ACTH peak?
8:30 am
what does ACTH mainly stimulate?
the zona fasciculata and zona reticularis
what is the clinical presentation of addison’s?
> or equal to 90% destruction of adrenal tissue by the time symptoms appear
with a decrease in glucocorticoid presentation in addison’s what will you see?
- fatigue
- weakness
- weight loss/anorexia
- myalgia/joint pain
- abdominal pain/diarrhea
- hypoglycemia
with a decrease in mineralcorticoid presentation in addison’s what will you see?
- hypotension, dizziness
- hyperkalemia, hyponatremia (salt craving)
-metabolic acidosis
with a decrease in androgen presentation in addison’s what will you see?
- decreased axillary and pubic hair
- loss of libido
- amenorrhea in women
what is the most characteristic clinical presentation of addison’s?
hyperpigmentation from increased ACTH (sun exposed areas)
what are the diagnostic tests for addison’s?
- morning serum cortisol
- ACTH levels
- high-dose ACTH stimulation test
what is a normal serum cortisol level?
10-20
what cortisol levels strongly suggest Adrenal insufficiency?
decrease in serum cortisol (< or equal to 3)
what is involved in ACTH level testing?
this is to obtain baseline level simultaneouslt with morning cortisol
what does increased ACTH levels indicate?
primary adrenal insufficiency (issue w/ adrenal gland)
what does decreased or normal ACTH suggest?
secondary/tertiary adrenal insufficiency
what does a high-dose ACTH stimulation test do?
measure a baseline serum sorticol and plasma ACTH
what is done during a high-dose ACTH stimulation test?
- administration of 250 mcg of cosynotropin (synthetic ACTH) IV or IM
- measure serum cortisol at 30 and 60 minutes
what does a decreased cortisol and increased ACTH level on high-dose ACTH stimulation test indicate?
primary adrenal insufficiency
what does a decreased cortisol and decreased or normal ACTH level on high-dose ACTH stimulation test indicate?
secondary adrenal insufficiency
what are the treatment options for addisons?
- glucocorticoid replacement
- mineralcorticoid replacement
- tx underlying cause
what does glucocorticoid treatment for addisons entail?
- use lowest tolerated dose to control sx
1. oral hydrocortisone in 2-3 divided doses- stress dosing
> used for illnesses and before surgery
> dose is 3x maintenance dose x3 days
- stress dosing
what does mineralcorticoid treatment for addisons entail?
- fludrocortisone
what is the MOA of fludrocortisone?
it is a mineralcorticoid agonist, but also stimulates glucocorticoid receptors
increases sodium and water resorption
duration of action 8-12 hours
side effects: fluid retention, hypertension, edema, hypokalemia, hyperglycemia
what is an adrenal crisis?
- a medical emergency more likely to occur in primary disease than secondary disease
- usually precipitated by severe stress (infxn, trauma, surgery)
what is the clinical presentation of an adrenal crisis?
- profound weakness
- abdominal pain- mimics abdominal emergency
- hypotension
- orthostasis
- shock
- fever- when precipitated by infection
what is the treatment for an adrenal crisis?
- IV fluid resuscitation
- hydrocortisone phosphate or hydrocortisone sodium 100- 300 mg IV over 30 seconds, then 50 mg every 6 hours
- treat electrolyte imbalances and hypoglycemia
- search for underlying condition and tx accordingly