HYPOADRENALISM DIAGNOSIS

suspected

Consider endocrinologist consultation

Exclude exogenous glucocorticoid exposure

Question 1 DOES THE PATIENT HAVE

Screening tests:

1.Circadian rhythm of plasma cortisol

2.Late-night salivary cortisol (2 measurements)

3.Urinary free cortisol (2 measurements)

4.The overnight 1-mg dexamethasone suppression tests (DST)

5.The 2-day 2 mg dexamethasone test

1. Circadian rhythm of plasma cortisol

Basal plasma cortisol - normal range 5-25g/dl

NON DIAGNOSTIC!

Midnight cortisol level normal value < 3g/dl

2. Midnight salivary cortisol

- 2 measurements

- Passive drooling/salivette

- Normal value 1 ng/ml (2.8nmol/l)

- value>2 ng/ml (5.5 syndrome

3. Urinary free cortisol

- 2 measurements

- 24 hour urine collection,

- refrigerated, not frozen

- Normal range 20-

- (50-250 nmol/24 h)

- Elevated level (2-syndrome

4. 1-mg overnight DST

- 1 mg DXM administered at 11-12 P.M.

- Plasma cortisol level measured next morning 8 A.M.

- A value < 1.8 g/dl (50nmol/l) good suppression

NO syndrome

5. Longer low-dose DST (2 mg/d for 48 h)

- 0.5 mg every 6 hours for 48 hours beginning 8 A.M. on day 0 - (2X2 mg)

- pl cortisol before first dose and 6 hours after last dose.

- A value < 1.8 g/dl (50nmol/l) good suppression NO syndrome

+ UFC on day 2 collected urine < 10g/24h

+ 17 HOCS

Question 2 What is the cause of

syndrome in this patient?

Tests

1. ACTH level

2. Plasma potassium, bicarbonate

3. High-dose DXM suppression test

4. CRH test

5. Inferior petrosal sinus sampling

6. CT, MRI pituitary, adrenal

7. Scintigraphy

8. Tumor markers

1. ACTH

- Serum ACTH - IRMA

- Normal range 9-52 pg/ml (2-11 pmol/l)

-

-

2. Potassium, bicarbonate

HYPOKALEMIC ALKALOSIS

Ectopic ACTH secretion

3. High-dose DXM suppression test

- 2 mg DXM every 6 hours for 48 hours

- Measure plasma or urinary free cortisol at 0 and

+48 hours

- Supression > 50% from basal value

disease

4. CRH test

- CRH 1g/kg or 100g I.V.

- Can be performed after DXM test

- Cortisol and ACTH measurements before and every 15 minutes after, for 2 hours

- Normal response ACTH and cortisol rise of 15-20%

-

5. Inferior petrosal sinus sampling

100 g CRH I.V.

- Measurement of peripheral and petrosal ACTH level at 2, 5 and 15 minutes after.

- Ratio petrosal sinus/periphery prior CRH > 2:1 pituitary source of ACTH oversecretion

- Ratio petrosal sinus/periphery after CRH > 3:1 pituitary source of ACTH oversecretion

- Ratio petrosal sinus/periphery < 1.4:1 ectopic ACTH secretion

6. CT/MRI pituitary

- Only after dynamic tests!

ACTH secreting pituitary microadenomas

6. CT/MRI - adrenal

Typical solitary left adrenal adenoma

Massive macronodular hyperplasia.

Adrenal glands are replaced by

multiple nodules (arrows)