Adrenal Gland Flashcards
anatomy of the adrenal gland
has the medulla and the cortex. Cortex consists of 3 zones.
Adrenal cortex hormones
- Glucocorticoids, produced in Zona Fasciculata (Cortisol) 2. Mineralcorticoids, produced in Zona Glomerulosa (aldosterone) 3. Sex steroids, produced in Zona Reticularis (Androgens)
Adrenal medulla hormones
produces catecholamines: epinephrine, NE and dopamine.
Cortisol test
24 HOUR URINE TEST IS BEST A random cortisol sample collection tells you nothing because cortisol levels naturally fluctuate throughout the day.
Dexamethasone Suppression Test
Dexamethasone is a synthetic glucocorticoid that is more potent than Cortisol Give a dose of dexamethasone and it should suppress pituitary activity. This test will tell you if the Cushings syndrome is adrenal or pituitary in nature.
ACTH
In patients that have an abnormal Dexamethasone suppression test, you will do an ACTH test to determine if the Cushings is ACTH dependent or not.
ACTH Stimulation Test
The most useful test for Adrenal Insufficiency It tests the adrenal response when pt given an ACTH-like substance. Normal response is a cortisol level greater than 20mg/dl, one hour later. Lack of a rise indicates adrenal insufficiency
CRH Stimulation Test
CRH can be given to evaluate to Pituitary response to stimulation from the Hypothalamus. Give CRH and measure Cortisol and ACTH This test is used to differentiate primary vs. secondary adrenal insufficiency.
Primary (Pituitary) Adrenal Insufficiency determined by CRH stim test
test will show elevated ACTH but no Cortisol production
Secondary Adrenal Insufficiency determined by CRH stimulation test
test will show Low ACTH and Low Cortisol
Aldostrone Concentration
Most important test to diagnose Hyper and Hypoaldosteronism. Can be measured in serum or in urine.
Testing for Primary Aldostronism
order an aldostrone concentration and a Plasma renin activity (PRA)
Plasma Renin Activity
when kidneys are stressed, PRA goes up. Elevated PRA seen in Hyperaldosteronism. This test measures the ability to convert Angiotensinogen to Angiotensin I
Cushings Syndrome
Excess ACTH Not typically an endogenous disease process, usually caused by medications.
Cushings Disease
Cushings syndrome but as a result of a pituitary adenoma. Get excess ACTH production from the pituitary.
Cushings diagnosis
- 24 hour urine cortisol (could also be 24 hour salivary cortisol) is the GOLD STANDARD. 2. Determine if the cortisol deficiency is ACTH suppressible or CRH sensitive by getting an ACTH suppression test and a CRH sensitivity test. This determines the level of the problem. 3. Get imaging for potential surgical fix.
Primary Cortisol and ACTH defeciency
There is low production at the Adrenal Level
Addisons disease or Adrenal insuffeciency
Secondary ACTH and Cortisol Defeciency
Because of some failure in the hypothalmic/Pituitary Axis
Primary Addisons Disease
Destruction of the Renal Cortex
- autoimmune disorder
- TB
- Chronic infection
Cortisol and Aldosterone levels are low
When you to an ACTH stimulation test, there is no increase in cortisol, this is how you know it is primary.
Secondary Addisons disease
Due to lack of ACTH
- Drugs
- Tumors
- infection of pituitary
Cortisol only is low
you do an ACTH stimulation test and you get an increase in cortisol
Addisons manifestations
Hypoglycemia
Weight loss
Fatigue
Hypotension
Dizziness
N/V/D
Tanning of skin
Diagnosing Addisons
- Look for Low cortisol Level–> 24 hour urine cortisol, plasma aldosterone
- Demonstrate if ACTH is sensitive–> ACTH sensitivity Test
If not ACTH sensitive –> Primary/Adrenal cause
If ACTH sensitive–> Secondary cause –> order CRH stimulation test: Hypothalmic or pituitary level.
- look for treatable cause–> imaging.
Primary Addisons treatment
Replacement therapy
Replace Cortisol levels with hydrocortisone.
Replace Aldosterone with Fludrocortisone.
Secondary Addisons Treatment
Find/treat tumors
stop the offending drugs
treat the infection
