Dynamic Function Testing

Question 1

Indication for dexamethasone-CRH test

Answer 1

Distinguish between pseudo-Cushing’s and Cushing’s syndrome

Question 2

Indication for 2 day low dose dexamethasone suppression test

Answer 2

Distinguish between pseudo- and Cushing’s syndrome

Question 3

Indication for IV 4mg dexamethasone suppression test

Answer 3

Avoid non-adherence and issues with first pass metabolism
Diagnose Cushing’s syndrome
Distinguish between Cushing’s disease and ectopic ACTH

Question 4

Indication for HDDST

Answer 4

Distinguish between ectopic and pituitary ACTH

Question 5

Indication for peripheral CRH test

Answer 5

Distinguish between ectopic and pituitary ACTH

Question 6

Indication for IPSS

Answer 6

Distinguish between ectopic and pituitary ACTH

Question 7

Tests for distinguishing between ectopic and pituitary ACTH secretion

Answer 7

HDDST
Peripheral CRH test
IPSS

Question 8

Additional tests for secondary adrenal insufficiency where Synacthen stimulation test is normal

Answer 8

Insulin tolerance test
Overnight metyrapone test

Question 9

Indication for glucagon stimulation test

Answer 9

Diagnosis of adult GH deficiency

Question 10

Tests for GH deficiency

Answer 10

Insulin tolerance test
Glucagon stimulation test
Arginine stimulation test

Question 11

Indication for arginine stimulation test

Answer 11

GH deficiency - preferred in neonates, young infants as fewer SEs/ADRs

Question 12

Indication for GnRH stimulation test

Answer 12

Differentiate between severe delayed puberty and hypogonadotropic hypogonadism

Question 13

Indication for growth hormone suppression test

Answer 13

Diagnose acromegaly

Question 14

Indication for growth hormone 5-point day curve

Answer 14

Alternative to GH suppression test in patients with diabetes in whom OGTT is contraindicated

Question 15

Indication for arginine stimulated copeptin test

Answer 15

Differentiate between central DI and primary polydipsia

Question 16

Indication for hypertonic saline stimulated copeptin test

Answer 16

Differentiate between central DI and primary polydipsia

Question 17

Indication for TRH test

Answer 17

Differentiate between thyroid hormone resistance and TSHoma

Question 18

Indication for T3 suppression test

Answer 18

Differentiate between thyroid hormone resistance and TSHoma where results are discordant eg TRH test suggests TSHoma but MRI is negative.

Question 19

Insulin tolerance test - indications

Answer 19

Ix secondary adrenal insufficiency
Ix GH deficiency

Question 20

Insulin tolerance test - contraindications

Answer 20

Hypoglycaemia risks ie epilepsy, IHD, cardiac arrhythmia, cerebrovascular disease