Cushing's

Question 1

what is cushing’s

Answer 1

state of increased circulating glucocorticoid

Question 2

causes divided into what

Answer 2

acth dependent and acth independent

Question 3

which causes of acth dependent

Answer 3

cushing’s disease (acth secreated from pituitary adenoma)
ectopic acth producing tumours
acth therapeutic adminsteration

Question 4

acth independent causes

Answer 4

adrenal tumour

glucocorticoid adminstration

Question 5

sx

Answer 5

striae
buffalo hump
amenorrhoea
round face
red face
weight gain
hirsuitism
osteoporosis
bruises
thin skin
oedema
hyperglycaemia
gynaecomastia
personality change
gi distress

Question 6

ix if suspect cushing’s syndrome

Answer 6

overnight 1 mg dex suppression test
OR
24 h raised cortisol

Question 7

what happens in dex suppression test if cushing’s syndrome

Answer 7

cortisol isn’t suppressed (it would usually be suppressed by the dex)

Question 8

if dex suppression test shows raised cortisol, what ix?

Answer 8

plasma ACTH

Question 9

if plasma ACTH low with raised cortisol

Answer 9

diagnosed as ACTH independent Cushing’s

Question 10

if ACTH high with raised cortisol, what to do?

Answer 10

48 h high dose dex suppression test (8mg)

Question 11

what do the results of high dose dex suppression test show

Answer 11

High dose causes suppression of ACTH secretion by pituitary. ∴ if pituitary cause, cortisol ↓. If non-pituitary (e.g. ectopic source/adrenal tumour) still high level of cortisol

Question 12

what other investigation must be done if ACTH independent cause

Answer 12

CT/MRI to find adrenal tumour or ectopic ACTH secreting tumour

Question 13

what is Conn’s syndrome

Answer 13

= primary hyperaldosteronism due to adrenal adenoma.
↑aldosterone -> sodium retention and potassium loss -> hypokalaemia and hypertension (aldosterone works @ collecting duct 3Na+reabsorbed, 2K+secreted)