Adrenal Pharm

Question 1

What are glucocoritcoid target tissues? (4)

Answer 1

Adipose, liver, muscle, CNS

Question 2

What are mineralocorticoid target tissues? (3)

Answer 2

Kidney, colon, sweat glands

Question 3

What is the name of synthetic ACTH?

Answer 3

Tetracosactide

Question 4

What is the short ACTH stimulation test? What is a normal result?

Answer 4

Measure blood cortisol before and after 250 mcg tetracosactide (synthetic ACTH). Normal: 1 hr later, cortisol > nl level + has at least doubled.

Question 5

What is done if the short ACTH stim test is abnormal? Why?

Answer 5

Long ACTH stimulation test b/c pituitary may be functioning but with smaller response than normal

Question 6

How does the long ACTH stimulation test work?

Answer 6

1 mg tetracosatide w mult administrations. Blood levels taken 1, 4, 8, and 24 hours later

Question 7

What long ACTH stim test result would be expected with primary Addison’s disease?

Answer 7

Cortisol level reduced at all timepoints.

Question 8

What long ACTH stim test result would be expected with secondary corticoadrenal insufficiency (adrenal is small but still responsive)

Answer 8

Delayed but normal response (increased cortisol)

Question 9

How does the urine test for hypercortisolism work? How many tests are required?

Answer 9

Tests FREE cortisol in 24 hr sample. High = overwhelms metabolic conversion to inactive cortisone, > 2 tests = hypercortisolism.

Question 10

How does the late night salivary cortisol test work?

Answer 10

Loss of circadian rhythm + absence of late night nadir on >2 tests suggests Cushing’s syndrome

Question 11

How should hypercortisolism be tested in pregnant women?

Answer 11

Urine free cortisol test.

Question 12

How should hypercortisolism be tested in epileptic patients?

Answer 12

Urine or salivary cortisol. Do not use dexamethasone levels as antiepileptic drugs enhance dex clearance

Question 13

What happens after hypercortisolism is confirmed? Why?

Answer 13

Need to determine ACTH levels. High = ACTH dependent disease. Low = ACTH independent disease.

Question 14

How does the Dexamethasone Challenge work?

Answer 14

Low dose (1 mg) overnight or 2 mg/d over 48 hrs, then measure cortisol. Lower than normal = axis working, rules out Cushing syndrome

Question 15

3 caveats to the dexamethasone challenge

Answer 15

1. Estrogens -> inc cortisol-binding globulin -> false-pos test. Need to stop for 6 weeks to do test 2. Antiepileptics and alcohol -> inc hepatic clearance. 3. Liver disease -> dec clearance.

Question 16

Why might a high dose Dex test be done?

Answer 16

8 mg overnight test. Even pituitary ACTH secreting tumor will respond -> dec cortisol. High dose -> negative feedback on pituitary ACTH-producing cells, but not on ectopic ACTH-producing cells or adrenal adenoma.

Question 17

What dex test results would be seen with Cushing Disease

Answer 17

Low: no dec in cortisol. High: suppresses cortisol.

Question 18

What dex test results would be seen with ectopic cells secreting ACTH?

Answer 18

Low and High dose both yield no suppression of cortisol.

Question 19

What dex test results would be seen with Cushing syndrome caused by an adrenal tumor?

Answer 19

Low ACTH. No response to low dose. High dose test usually not needed.

Question 20

When would the CRF/H stimulation test be used?

Answer 20

Once Cushing syndrome is diagnosed to distinguish between Cushing disease (pituitary issue) and ectopic ACTH-secreting tumors.

Question 21

What are the possible CRH stim test results and coordinating conditions?

Answer 21

Unresponsive: ectopic tumors and adrenal tumors. Responsive: pituitary tumors - CRF -> inc ACTH & cortisol.

Question 22

How is ACTH measured in the CRF stimulation test?

Answer 22

Concurrent pituitary venous drainage and peripheral venous sampling of ACTH. 2.5x difference = Cushing’s of pituitary origin. Equal = ectopic tumor.

Question 23

Effect of glucocorticoids on CV system

Answer 23

Pos inotropic effect, increased BP d/t Na & water reten

Question 24

Effect of glucocorticoids on CNS

Answer 24

Lowers seizure threshold. Behavior changes e.g. mood dep or elevation, euphoria, restlessness. Anxiety and psychosis possible.

Question 25

Effect of glucocorticoids on GI system

Answer 25

Increased gastric acid and pepsin, may suppress local immune response v h. pylori -> ulcer, decreased Ca abs from gut

Question 26

Effect of glucocorticoids on bone metabolism

Answer 26

Direct inhib of osteoblasts w 2* stim of PTH -> stim osteoclasts. Net absorption of bone matrix.

Question 27

Effect of glucocorticoids on skeletal muscle

Answer 27

Weakness, fatigue, muscle wasting d/t loss of protein, hypokalemia.

Question 28

Hematological effect of glucocorticoids

Answer 28

Dec lymphocytes (T cells dec > B cells) -> susceptible to infection. Dec eosinophils & basophils. Increased neutrophils and erythrocytes. Inhibits leuocyte extravasation.