Endocrine Function III Part 3 Flashcards Preview

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Flashcards in Endocrine Function III Part 3 Deck (20):
0

What is the clinical use of the corticotropin releasing hormone (CRH) test?

Differentiates secondary (pituitary) and tertiary (hypothalamic) adrenal sufficiency

1

Overnight Dexamethasone Suppression Test (screening test)
-Principle

Feedback mechanism of hypersecretion can be tested by administering a potent glucocorticoid and judging suppression of ACTH secretion by measuring serum or urine cortisol levels

2

Overnight Dexamethasone Suppression Test (screening test)
-Diagnostic Use

Differentiate normal patient from Cushing's syndrome, either due to Cushing's disease, adrenal tumor, or ectopic ACTH syndrome

3

Overnight Dexamethasone Suppression Test (screening test)
-expected normal response

decreased cortisol (<3 ug/dL)

4

Overnight Dexamethasone Suppression Test (screening test)
-cause of abnormal results

increased cortisol (>10 ug/dL) = Cushing's Syndrome

5

Which causes of Cushing's syndrome may be differentiated using the high-dose test?

adrenal tumors, nonendocrine ACTH-secreting tumors, and pituitary Cushing's disease

6

What do normal results look like in high dose dexamethasone suppression test look like?

50% suppression of cortisol production

7

How do abnormal results differ in Cushing's and adrenal/ectopic tumors during the high dose test?

Cushing's = most suppress cortisol production
Adrenal/ectopic tumors = no change in cortisol levels

8

Name the three principle hormones classified as catecholamines and their sites of synthesis.

1 epinephrine (80-90% medulla production)
2 norepinephrine (10-20% medulla production)
3 dopamine (small amount produced in adrenal medulla)

9

These catecholamines have a marked influence on the vascular system.

dopamine and norepinephrine

10

This catacholamine influences metabolic processes, especially carbohydrate metabolism.

epinephrine

11

This catecholamine inhibits phenylethanolamine-N-methyltransferase

epinephrine

12

This catecholamine inhibits tyrosine hydroxylase.

Norepinephrine

13

What is the cause of pheochromocytomas?

tumor in adrenal medulla, too much catecholamines

14

What is the principle clinical symptom of pheochromocytomas?

hypertension

15

What is the best specific urine screening test for pheochromocytomas?

urinary metanephrines

16

What is the best diagnostic test for pheochromocytomas?

urinary VMA

17

What is the commonly affected age group of neuroblastomas?

pediatric

18

What are the clinical symptoms for neuroblastomas?

tumor in or near adrenal gland producing a lot of dopamine, causing transient hypertension and tachycardia

19

What is the best specific urine screening test for neuroblastomas?

urinary homovanillic acid (HVA) (diagnostic)