Hypercortisolism

Question 1

ACTH dependent cushings syndrome is due to what causes?

Answer 1

pituitary / hypothalamus / ectopic tumor

Question 2

what are the levels of cortisol and ACTH in ACTH dependent cushings syndrome?

Answer 2

• high cortisol

- high ACTH

Question 3

ACTH independent cushings syndrome is due to what cause?

Answer 3

adrenal gland pathology

Question 4

what are the levels of cortisol and ACTH in ACTH independent cushings syndrome?

Answer 4

• high cortisol

- low ACTH

Question 5

features of ectopic ACTH cushings syndrome

Answer 5

• rapid progression
• elevated ACTH (5-10x normal cushings)
• hirsutism
• hyperpigmentation

Question 6

steps to diagnose cushings

Answer 6

1. confirm hypercortisolemia
2. determine subtype
3. localize source of overproduction

Question 7

confirmation of hypercortisolemia

Answer 7

• 24 hour urine collection for free cortisol excretion
• 11 pm salivary or serum cortisol
• low dose dexamethasone suppression test (DST)

Question 8

does a normal 24 hour urine test result exclude cushings?

Answer 8

no

Question 9

what is pseudo cushings syndrome?

Answer 9

elevated cortisol levels resulting from an underlying condition / illness which stimulates the HPA axis and thus mimics true cushings syndrome

Question 10

what are the steps of treatment for pseudo cushings syndrome?

Answer 10

• delay testing until correction of underlying cause
• avoid 24 hour urine collection as means of diagnosis
• use overnight low dose DST

Question 11

what is the rationale of the midnight salivary cortisol testing?

Answer 11

demonstrates disrupted circadian rhythm of cortisol secretion

Question 12

for “soft” clinical findings of cushings syndrome, what tests should you use?

Answer 12

• midnight salivary cortisol

- low dose DST

Question 13

high cortisol
low ACTH

which subtype of cushings?

Answer 13

adrenal

Question 14

high cortisol
high ACTH

which subtype of cushings?

Answer 14

pituitary / hypothalamus / ectopic ACTH

Question 15

what two tests are done to differentiate pituitary vs ectopic etiologies of cushings?

Answer 15

• inferior petrosal sinus sampling

- high dose dexamethasone suppression test (DST)

Question 16

what does a high dose DST show for a pituitary tumor?

Answer 16

cortisol production is suppressed

Question 17

what does a high dose DST show for an ectopic tumor?

Answer 17

does NOT show cortisol suppression

Question 18

what ratio of inferior petrosal sinus to peripheral vein ACTH levels indicates pituitary source?

Answer 18

IPS:P over 2:1

Question 19

what are the indications for bilateral total adrenalectomy?

Answer 19

• TSS and radiation failure

- advanced cushings disease

Question 20

aminoglutethimide: MOA and effects

Answer 20

• blocks conversion of cholesterol to pregnenolone

- lowers cortisol, aldosterone, androgens

Question 21

ketoconazole: MOA and effects

Answer 21

• blocks 11-B-hydroxylase

- lowers cortisol, aldosterone, DHEA

Question 22

mitotane: MOA and effects

Answer 22

• blocks 11-B-hydroxylase

- lowers cortisol, aldosterone, DHEA

Question 23

• blocks conversion of cholesterol to pregnenolone

- lowers cortisol, aldosterone, androgens

Answer 23

aminoglutethimide

Question 24

• blocks 11-B-hydroxylase

- lowers cortisol, aldosterone, DHEA

Answer 24

ketoconazole, mitotane