Let's try this again Flashcards
Adrenal Gland destruction (lack of cortisol AND aldosterone)
primary adrenocortical insufficiency (addison’s disease)
Pituitary failure of ACTH secretion (lack of cortisol only)
*isolated glucocorticoid insuffiency (aka aldosterone is working, just cortisol effected)
Secondary adrenocortical insufficiency
etiologies of primary adrenocortical insufficency? What diseases is it frequently assoicated with?
Autoimmune- Most common cause in US
Infection- (most common in developing countries- tuberculosis, HIV)
Vascular: thrombosis or hemorrhage in adrenal gland
others: medications (e.g, Ketoconazole, rifampin)
Frequently assoicated with: Vitiligo, Type 1 DM, hashimoto’s thyroiditis, pernicious anemia
etiologies of secondary adrenocortical insufficiency?
History of exogenous glucorticoid use
hypopituitarism
pituitary lesions, metastatic breast, prostate, lung cancer, LT glucocortiocoid tx
what symptoms would you see with (primary) Addison’s disease? Lab findings?
symptoms due to lack of sex hormones (women may have loss of libido, amenorrhera & loss of axillary pubic hair)
Hyperpigmentation
orthostatic hypotension
What labs can be used as baseline labs for adrenal insufficiency? What levels would you expect?
8am ACTH, cortisol and renin levels obtained (increased renin, especially with primary)
* elevated ACTH in primary, decreased in secondary
* hypoglycemia in
* Primary- HYPOnatremia, HYPERkalemia, & non-anion gap metabolic acidosis (due to decreased aldosterone)
ways to screen for adrenal insufficiency? What result confirms adrenal insufficiency
High dose ACTH (cosyntropin) stimulation test
adrenal insufficiency if insufficient or absent rise in serum cortisol after ACTH administration
*normal response is rise in serum cortisol after ACTH administration
Precipitated by “stressful” event (eg illness, surgery, trauma, volume loss, hypothermia, MI, fever, sepsis, hypoglycemia, steroid withdrawl)
Adrenal Addisonian crisis
Etiologies of adrenal crisis?
Abrupt withdrawal of glucocortioids (especially without tapering)- most common cause
Clinical Manifestation Adrenal crisis
Shock is the primary manifestation- hypotension, hypovolemia (nonspecific symptoms)
Clinical Manifestation Adrenal crisis
Shock is the primary manifestation- hypotension, hypovolemia (nonspecific symptoms)
dehydration
Diagnosis of adrenal crisis has what significant features?
Hyponatremia, HYPERkalemia, hypoglycemia, HYPOtension
Cushing’s disease vs Cushing’s syndrome
- Cushing’s disease: is when the pituitary gland causes ACTH production (about 2/3 of cases of endogenous cushing’s syndrome)
- Cushing’s syndrome is excess glucocorticoids
Causes of Cushing’s syndrome
- long-term high dose glucocorticoid therapy most common cause overall
- ectopic ACTH-producing tumor (eg, small cell lung cancer, medullary thyroid cancer
- adrenal tumor (adenoma)- secretion of excess cortisol
common signs of cushing’s syndrome
moon facies, obesity, buffalo hump, supraclavicular fat pads, thin extremities
Acanthosis nigricans
hypertension
hirtuisim
Three screening tests for cushing’s? What happens if the screening is positive?
24 hour urinary free cortisol (most specific) (at least 2 tests)
salivary cortisol (2-3 times)
low-dose overnight dexmethasone suppression test
*ALL tests likely needs a second confirmatory test
If test is positive, determine if ACTH independent or ACTH dependent
*THEN (and only then) order appropriate imaging
hyperpigmentation can be seen in?
Priamry adrenal insufficiency
ACTH-dependent Cushing’s syndrome (pituitary adenoma, ectopic ACTH, medullary cancer of thyroid, pheochromocytoma)
what disease are considered ACTH-dependent Cushing’s?
Pituitary adenoma (Cushing’s disease)
ectopic ACTH syndrome (oat cell ca, carinoid tumor, medullary ca of the thyroid, pheochromocytomas)
what diseases are considered ACTH independent cushing’s (much in higher in kids)
Iatrogenic- exogenous glucocorticoids
adrenal adenomas
adrenal cancers
micro and macronodular hyperplasia (rare)
Test that measures total cortisol(so not for women on OCPs)
substance should turn off CRH and ACTH production (and turn off signal for cortisol)
Dexmethasone suppresion test
After diagnosis of 1-2 postives with one of the three tests, what should you do to determine if cushing’s is ACTH independent or dependent? what distinguishes them?
Order an AM plasma ACTH
* if plasma ACTH is undetectable- ACTH Independent
* if plasma ACTH is detectable (normal or elevated)- ACTH dependent
what imaging would you order for ACTH dependent cushings? ACTH independent? what would you do if the ACTH dependent imaging is negative?
ACTH dependent: Pituitary MRI (cushing’s disease)
ACTH Independent: CT of adrenal glands (Cortisol producing tumor)
*If MRI is negative look for ectopic producing tumor- such as OAT cell carcinoma, carcinoid tumor, medullary CA, pheochromocytoma
why shouldn’t you do imaging without a clear diagnosis of cushing’s?
high number of incidentalomas- must have clear biochemical diagnosis and localization of where the problem is
when determining between cushing’s disease and ectopic ACTH production (both have high ACTH results from checking ACTH plasma levels) how could you determine which is which?
Give a high dose dexamethasone suppresion test.
* If there is NO suppresion: Ectopic ACTH producing tumor
* * if there is suppression: Cushing’s disease