ABSITE Review - Adrenal Flashcards
What is the arterial supply to the adrenals?
Inferior phrenic artery, aorta and renal artery
What is the venous drainage of the adrenals?
Left adrenal vein goe to left renal vein; and Right adrenal vein goes to IVC.
When is an adrenalectomy indicated?
If mass has ominous characteristics (nonhomogenous) or is >4-6cm, functioning or enlarging
What is th work up needed for an adrenal incidentaloma?
Serum K, urine metanephrines/VMA/catecholamines, urinary hydroxycorticosteroids, plasma renin and aldosterone levels if HTN or low K
CXR stool guaiac and colonoscopy, mammogram
What are some common metastases to the adrenal gland?
Lung CA (#1), breast CA, melanoma, renal CA
What are the layers of the adrenal cortex and what they produce?
Glomerulosa - aldosterone; Fasciculata - Glucocorticoids; Reticularis - Androgens/Estrogens
What is the inital compound use by the adrenal?
Cholesterol
What is the function of aldosterone?
Stimulates renal Na resorption and secretion of K , hydrogen ions and ammonia
What stimulates the secretion of aldosterone?
Angiotensin II an hyperkalemia, and to some extent ACTH
What is the MC enzyme deficiency in congenital adrenal hyperplasia? What is the MC symptoms?
21-hydroxylase deficiency
Sxs: Precocius puberty in males, virilization in females, increase in 17-OH progesterone lead to increase prod of testosterone, Salt-wasting
What is the second MC enzyme deficiency in congenital adrenal hyperplasia? What is the MC symptoms?
11-hydroxylase deficiency
Sxs: precocious puberty in males, virilization in females, increase 11-deoxycortisone, Salt-saving
What are some causes of Primary hyperaldosteronism?
Adenoma (80-90%), Hyperplasia (10-20%), ovarian tumors, cancer
What are some causes of Secondary hyperaldosteronism?
More common than primary disease
CHF, renal artery stenosis, liver failure, pregnancy, diuretics, Bartter’s syndrome (renin-secreting tumor)
What is the main diagnostic test to differentiate between Primary and Secondary Hyperaldosteronism?
Primary - low renin
Secondary - high renin
What is the main diagnostic findings of Primary Hyperaldosteronism?
Urine aldosterone after salt-load (will stay high)
Low serum K, High urine K, High serum Na, Metabolic Alkalosis
Plasma renin activity will be low
Aldosterone:renin ratio > 20
What are some localizing studies that can be used for Primary Hyperaldosteronism?
MRI, NP-59 scintigraphy (differentiate adenoma from hyperplasia), adrenal venous sampling
What is the treatment for Primary Hyperaldosteronism?
Adenoma - resection
Hyperplasia - Medical therapy first with spironolactone, CCBs, K
If bilateral resection is performed (usually done for refractory hypoK), pt will need fludrocortisone postop
What is the #1 cause of adrenal insufficiency?
Withdrawal of exogenous steroids
What is the #1 primary disease of adrenal insufficiency?
Autoimmune disease
What diagnostic findings are seen in adrenal insufficiency?
Low serum Na, High serum K, ACTH stimulation test
What step by step work up done for hypercortisolism?
1st - 24-hour urine cortisol (most sensitive test)
2nd - low-dose overnight dexamethasone suppression test. If cortisol is low, the dx is Cushing’s disease; if high, go to 3rd.
3rd - measure serum ACTH. If high, dx is either ectopic ACTH or pituitary tumor –> go to 4th; if low, pt has cortisol-secreting tumor.
4th - High-dose overnight dexamethasone suppression test. Positive = pituitary origin; negatiove = ectopic origin of ACTH.
5th - CRH test –> pituitary adenomas will increase ACTH; ectopic producers will have no change in ACTH
What is the #1 cause of noniatrogenic cause of Cushing’s syndrome?
Cushing’s disease (Pituitary adenoma) 70-80% cases
What is the #2 cause of noniatrogenic cause of Cushing’s syndrome?
Ectopic ACTH - most commonly small cell lung CA
When is an bilateral adrenalectomy needed?
Adrenal hyperplasia, pts with ectopic ACTH from tumor that is unresectable or from pituitary adenoma that cannot be found
What is the AA needed for catecholamine production?
Tyrosine
What is the reta-limiting step enzyme in catecholamine production?
Tyrosine hydroxylase (tyrosine to dopa)
What is the enzyme tha converts norepinephrine to epinephrine?
PNMT which is only found in the adrenal medulla
In addition to the adrenal gland, where can pheochromocytomas be found?
Organ of Zuckerkandl
From which cells, the pheochromocytomas originate?
Chromaffin cells
What is the 10% rule of pheochromocytomas?
10% malignant, 10% bilateral, 10% in children, 10% familial, 10% extra-adrenal
Which side of adrenal gland are pheochromocytomas most commonly found?
Right side
What diagnostic studies are used for pheochromocytoma?
VMA most sensitive
MIBG scan
Clonidine suppression test
What preoperative preparation is need for pheochromocytoma?
Volume replacement, alpha-blockade first (phenoxybenzamine –> avoids HTN crisis); then beta-blocker if patient has tachycardia or arrhythmias
What happens if you give beta-blockade before alpha-blockade?
HTN crisis that can leed to heart failure
During surgery, what maneuver can be done to avoid spilling of catecholamines?
Ligate adrenal veins first
What can falsely elevated VMA?
Coffee, Tea, Fruits, Vanilla, Iodine contrast, Labetalol, alpaha and beta-blockers
