Eval Of Hormones

Question 0

Recommended tests for Cushing’s syndrome

Answer 0

UFC (urinary free cortisol)
Low dose or overnight dexamethasone test
Night-time salivary cortisol

Question 1

Lab findings for Cushing’s syndrome

Answer 1

CBC- leukocytosis, lymphocytopenia, and decreased eosinophils

CMP- hyperglycemia, hypokalemia, and hypernatremia

Thyroid function- slightly low T3 & TSH

Question 2

What problem may occur with the 24-hr urinary free cortisol (UFC) that may camouflage a patient with Cushing’s?

Answer 2

Values may appear normal if subjects cortisol is high at night and low during the day
Loose diurnal component while might have avg amount

Question 3

What test would accurately reflect the diurnal pattern of cortisol?

Answer 3

Normal individuals and patients with pseudo-Cushing states have a pronounced diurnal rhythm with the highest values in the morning and the lowest at night
Patients with Cushing’s syndrome lack their diurnal variation of cortisol

THE DIURNAL PLASMA CORTISOL TEST - great because it reflects this variation

Question 4

Test that is easier for pt to carry out and still reflects diurnal pattern

Answer 4

Diurnal salivary cortisol test

Question 5

What does the Overnight dexamethasone test show?

Answer 5

Dexamethasone is a synthetic steroid that will suppress ACTH secretion in normal ppl
This negative feedback system does not work properly in patients with Cushing’s syndrome (cortisol production not suppressed)

Question 6

Addison’s disease- primary adrenal insufficiency

Lab findings

Answer 6

CMP- hyponatremia, hyperkalemia, hyperglycemia
CBC- normocytic normochromic anemia
Thyroid function- increased thyroid stimulating hormone (TSH)

Question 7

What does Rapid ACTH stimulation test show?

Answer 7

Pre- blood draw
Administration of synthetic ACTH
30-60 min after, 2 blood samples drawn, one for cortisol and one for aldosterone
For DX of Addison’s both cortisol and aldosterone show minimal or no change in response toACTH

Question 8

Synacthen test- what does it measure?

Answer 8

Uses synthetic ACTH analogue to trigger adrenal glands to produce cortisol. If this doesn’t happen, know there’s dysfunction in adrenals

Question 9

Cushing’s syndrome- adrenal function testing

Answer 9

Cortisol- high
ACTH- low

Adrenals themselves overproducing cortisol, pituitary just fine, so down-regulate ACTH

Question 11

Cushing’s disease- adrenal function testing

Answer 11

Cortisol- high
ACTH- high

Problem is in pituitary - overproducing ACTH with is overstimulating the adrenal glands

Question 12

Addison’s disease

Answer 12

Cortisol- low

ACTH level- high

Question 13

Hypopituitarism

Answer 13

Cortisol- low

ACTH level- low

Question 14

Salivary Adrenal Function Test:

Answer 14

The Preferred Test for Adrenal Fatigue
Use 1 day collection (4 vials) as baseline.
Have patient record S&S, date and time of sample on separate sheet.
If possible, take blood sugar at same time as cortisol level

Question 15

Growth hormone

Answer 15

Hypothalamus releases GHRH
Anterior Pituitary releases GH
GH induces release of Insulin-like Growth Factor
Triggers = Tissue growth/ repair
Increase protein synthesis, growth, etc.
Increase GH and release of somatostatin 
shuts off GHRH and GH release

Question 16

Quantitative GH

Answer 16

fasting level

isn’t a good test

Question 17

Provocative test for susptected deficiency

Answer 17

Hypoglycemia causes GH levels to rise

Question 18

Suppression test

Answer 18

Hyperglycemia suppresses GH (should see suppression in GH to correct for this)

Question 19

Testing Insulin-like Growth Factor
 (IGF)

Answer 19

IGF-1 levels reflect average daily levels of GH- easier to test
Low values imply deficiency
High values are seen in acromegaly and gigantism
IGF-1 levels do not fluctuate throughout the day

Question 20

Regulation of PTH

Answer 20

the dominant regulator of PTH is plasm Ca2+

PTH secretion responds to small alterations in plasma Ca2+ immediately (within seconds)

Question 21

Function of PTH

Answer 21

PTH acts directly on the bones to stimulate Ca resorption and kidney to stimulate Ca reabsorption
PTH also acts indirectly on intestine by stimulating Vit D synthesis

Question 22

Hypercalcemia results from

Answer 22

Combined effects of PTH-induced bone resorption, intestinal calcium absorption and renal tubular reabsorption

Question 23

Hypocalcemia occurs when

Answer 23

there is inadequate response of the Vitamin D-PTH axis to hypocalcemic stimuli

Question 24

Pseudohypoparathyroidism

Answer 24

Due to defect in PTH receptor-adenylate cyclase complex

- present as hypothyroid patient because parathyroid receptors aren’t working properly

Question 25

Parathyroid hormone testing

Answer 25

diurnal variation - highest at 2am

levels vary with diet so need fasting specimen

Question 26

Primary hyperparathyroidism test

Answer 26

high PTH and high calcium levels (due to parathyroid neoplasm)

Question 27

Secondary hyperparathyroidism test

Answer 27

high PTH and normal/slightly low calcium levels (early chronic renal failure)

Question 28

Tertiary hyperparathyroidism test

Answer 28

high PTH and high calcium levels (late stage chronic renal failure)