Cushings, Addisons

Question 1

results of dexamethasone test

Answer 1

give dexamethasone = suppresses ACTH production
in normal - cortisol levels would fall
in cushings - cortisol levels stay the same
THEN
check plasma ACTH levels
if HIGH ACTH - (but cortisol still high) then must be a pituitary issue = ACTH DEPENDENT - pituitary adenoma (cushings disease) or ectopic non pit acth secreting tumour
if LOW ACTH = cortisol being produced elsewhere or is an adrenal issue = ACTH INDEPENDENT - exogenous steroid use or adrenal adenocarninoma

Question 2

result of desamethasone test of ACTH INDEPENDENT -

Answer 2

cortisol levels stay the same = cushings
type?
test plasma ACTH -
independent so its a adrenal issue = adrenal adenocarinoma or exogenous steroid use
=LOW ACTH

Question 3

result of desamethasone test of ACTH DEPENDENT -

Answer 3

cortisol level level not suppressed - so is cushings
type?
test plasma ACTH
pituitary is the issue as it is ACTH dependent
= cushings disease (pituitary adenocarcinoma)
ectopic acth releasing carinoma non pituitary

Question 4

what is the difference between cushings syndrome and disease

Answer 4

cushngs diesease is cushings sydrom caused specifically by a pituitary adenoma

Question 5

what i cushings sydrome

Answer 5

XS cortisol = loss of hypothalamic pit. axis

feedbackk and loss of circadian rhythims

Question 6

what stimulates cortisol release and where from

Answer 6

CRH released from the hypothalamus –> anteriori pit. releases ACTH. acts on adrena cortex which releases cortisol (then neg feedback on ACTH and CRH)

Question 7

ACTH independent cushings causes

Answer 7

endogenous cortisol by adrenal adenocarcinoma

exogenous steroids - iatrogenic

Question 8

signs of cushings

Answer 8

buffalo hump
facial plethora/moonface
central obesity

abdo stria
easy bruising
thin skin

osteoporosis
hyperglycasemia
HTN

Question 9

symptoms of cushings

Answer 9

weight gain
acne
depression, lethargy, irritable
amenorrhoea
poor libido/erectile dysfunction
muscle weakness
back pain
Hirsutism (excessive hair growth - in women also)

Question 10

what does cortisol do

Answer 10

Gluconeogenis
fat deposition
protein breakdown (tissue breakdown)
increase glycogen store
retain sodium, loss potassium water clearance
XS cortisol inhibits gonadotrophin releasing horomone

Question 11

causes of cushing syndrome

Answer 11

commonest cause is iatrogenic - oral steroid excess cause
commonest endogenous cause is cushings disease
other is adrenal carcinoma
ectopic ACTH secreting tumour

Question 12

Treatment of cushing syndrome

Answer 12

if iatrogenic= stop steroids
if cushings disease= transphenoidal surgery (pit adenocarcinoma) radiotherapy
any other carcinoma/ectopics= surgery
before surgery reduce cortisol with metryapone or ketoconazole
after surgery replace cortisol with hydrocortisone

Question 13

what is addisons

Answer 13

a subset of primary adrenal insufficiency
autoimmuune destruction of adrenal cortex = shortage of miniralicorticoids and glucocorticoids and sex steroids (androgens)

Question 14

what is levels of CRH ACTH and cortisol in addisons

Answer 14

cortisol low as adrenal cortex destruction

therefore no neg feedback so CRH and ACTH HIGH

Question 15

signs of addisons

Answer 15

PIGMENTATION - dull grey
palmar creases and BUCCAL PIGMENTATION
post dural HYPOtenstion
vitiligo (opp to hirsutism in cushings) = hair loss
hyperkalcaemia hyponatrieamia dehydration hypovolaemia (aldosterone)

Question 16

symptoms of addisons

Answer 16

tanned toned tired tearful
N+V 
abdo pain
lean
tanned (grey skin)
dizzy
fatigue (tired)
constip and diarrhoea
anorexia (probs why toned)

Question 17

why hypotension in addisons

Answer 17

decrease in aldosterone as adrenal cortex destruction
less K excreted in kidneys (hypERkalaemia)
less Na reabsorption = hyPO natraemia
less water reabsorbed = hypOvolaemia = decrease BP = postdural HYPOTENSION

Question 18

mx of addisons

Answer 18

replace cortisol = hydrocortisone or prednisolone
replace aldosterone (mineralcorticoids)= fludrocortisone
lifelong = carry steroid card and keep spare (addisons crisis)

Question 19

what is addisons crisis

Answer 19

Hypovolaemic Hypotension in response to major stressor as this increases steroid need
danger of hypoglycasemia == shock
loss of consiousness

Question 20

how to treat addisons crisis

Answer 20

treat with steroids and fluids = IM hydrocortisone

IV saline

Question 21

Investigations for addisons disease

Answer 21

U&Es = electrolytes= low Na high K, high urea
serum cortisol= low between 0800 and 0900
ACTH stimulation test= cortisol still low post tetracosactide (test after 30mins)
serum renin and aldesterone = high renin and low aldesterone
adrenal antibodies
glucose test= low