Adrenocortical

Question 1

Cortisol is produced in the ____ of the adrenal cortex from cholesterol through a series of enzymatic reactions, the rates of which are controlled by ____

Answer 1

-zona fasciculata
-ACTH

Question 2

ACTH release during a 24 hour cycle occurs in several bursts. The largest one is ___

Answer 2

in the morning hours (between 5 and 8 a.m.)

lowest = midnight to 4am

Question 3

Since the half-life of ACTH in circulation is only about 5 minutes while that of cortisol is about 65 minutes, the ____ burst responses in the blood are less pronounced than those of ACTH and also lag behind

Answer 3

cortisol

Question 4

Cortisol Major Effects

Answer 4

Catabolic
-Increase protein catabolism and lipid breakdown
-Inhibits protein synthesis
-Increases glucose
-Sensitize arterioles to NE
-Anti-inflammatory
-Immunosuppressive
-Redistributes fat

RASI the PIG

Question 5

The level of circulating transcortin rises in ____ and with estrogen therapy, resulting in an ____ of total blood cortisol; the free remains ____, since it is regulated by feedback mechanism.

Answer 5

-pregnancy
-elevation
-normal

Question 6

Increased Cortisol Values =

Answer 6

-Cushing’s syndrome
-Pregnancy
-Estrogen treatment
-Alcoholism
-Stress
-Starvation

SPACES

Question 7

Decreased Cortisol Values =

Answer 7

-Addison’s disease
-Chronic illnesses
-Adrenogenital syndrome

ACA

Question 8

Urinary Free Cortisol Values seen in Cushing’s syndrome are almost always higher than ___

Answer 8

120 ug/day

Question 9

ACTH test to differentiate primary from secondary adrenal insufficiency

Answer 9

Primary: 200+ (high)

Secondary: < 75 (low)

Question 10

To determine the cause of Cushing’s syndrome

Answer 10

-Pituitary adenoma and ectopic ACTH production = 200+.

-Adrenal adenomas or carcinomas that produce cortisol in excess, ACTH levels are low

Question 11

In the demonstration of ectopic ACTH production by rapidly growing malignancies before the full-blown Cushing’s syndrome develops:

Answer 11

ACTH 300+

Question 12

Dexamethasone Test: Short Version

Answer 12

-Serum cortisol less than 5 = normal
-Serum cortisol greater than 10 = possible Cushing’s syndrome

*Disadv: false pos
*Adv: simple, outpt

Question 13

Low dose Dexamethasone Test

Answer 13

-Serum cortisol less than = normal
-Serum cortisol greater than 10 = Cushing’s syndrome

*Fewer false pos
*More false neg
(compared to short test)

Question 14

High dose Dexamethasone Test

Answer 14

-Pts with Cushing’s disease due to an ACTH-secreting pituitary adenoma usually show suppression of urinary free cortisol and 17-hydroxycorticosteroid excretion greater than or equal to 50% of baseline by the fourth day; lack of diurnal variation in plasma cortisol; and plasma cortisol <= 10 at 8 a.m. on the fifth day
-Suppression = Cushing’s

-Not suppressed = adrenal adenoma or carcinoma or ectopic ACTH

Question 15

Carcinomas of the adrenal cortex usually produce much ____ amounts of steroids including androgens (testosterone) than do adenomas

Answer 15

Larger

Question 16

The short ACTH stimulation test

Answer 16

A normal response is a rise of at least 7 after 30 minutes and a rise of 11 after 60 minutes

-Normal = nothing further needs to be done regarding assessment of adrenocortical function

-Subnormal or no response = long test indicated

Question 17

The long ACTH stimulation test

Answer 17

This test distinguishes primary from secondary hypocortisolism

-Serum cortisol values that are over 20 exclude primary adrenal insufficiency

-Little to no increased in cortisol = primary adrenal failure, adrenal hyperplasia of 21/17 deficiencies

Question 18

CRH STIMULATION TEST

Answer 18

3* Insufficiency

-Cushing’s disease: serum cortisol >29.7 or a rise of >25%

Question 19

SERUM 17-a-HYDROXYPROGESTERONE

Answer 19

This test is used in the differential diagnosis of adrenogenital syndrome (congenital adrenal hyperplasia) to detect 21-hydroxylase deficiency

-Less than 100 ng/dL

-In patients with 21-hydroxylase deficiency: greater than 1000

Question 20

Electrolytes, Glucose, BUN, and Urinalysis in Cushing’s syndrome

Answer 20

-Low K
-Low Cl
-High bicarb
-Glucose may be high
-BUN moderately high
-Glucosuria may be present

LOW KC HIGH BGBG

Question 21

Electrolytes, Glucose, BUN, and Urinalysis in Addison’s

Answer 21

-High K
-Low bicarb
-Low glucose
-High urea nitrogen may be present

Question 21

Diagnosis of 21-Hydroxylase Deficiency

Answer 21

Serum 17-a-hydroxyprogesterone may be elevated more than 10-fold, which is virtually diagnostic

Question 22

Aldosteronism (Conn’s)

Answer 22

1* = renin reduced
2* = renin elevated