Cushings

Question 1

what is cushings

Answer 1

chronic excess cortisol and loss of normal feedback and circadian rhythm

Question 2

what is the commonest cause

Answer 2

iatrogenic- steroids used in high doses for RA etc

Question 3

what can the endogenous causes be split into

Answer 3

ACTH dependent and independent

Question 4

what are the conditions of ACTH dependent

Answer 4

Cushings disease (pituitary adenoma); ectopic ACTH production (SCLC, carcinoid tumours); nearly ectopic CRF production (thyroid, prostate)

Question 5

what are the specific features of ectopic ACTH dependent production

Answer 5

pigmentation (from high ACTH), hypokalaemic metabolic acidosis, weight loss, hyperglycaemia. classical features absent

Question 6

what are the conditions of ACTH independent production

Answer 6

adrenal adenoma/carcinoma; adrenal nodular hyperplasia; iatrogenic; rare- Carney complex

Question 7

symptoms

Answer 7

weight gain; mood change- depression, lethargy etc; proximal weakness; gonadal dysfunction; acne

Question 8

signs

Answer 8

upper body obesity, central obesity, plethoric moon face; skin and muscle atrophy; bruises; purple abdo striae; osteoporosis; incr BP; incr glucose; poor healing; supra clavicular fat

Question 9

tests

Answer 9

1st- overnight dexamethasone (doesn’t suppress cortisol levels in cushings)- 1mg PO at midnight measure cortisol at 8am. 24h urinary free cortisol. 2nd- 48h dexamethasone test. 3rd- localisation

Question 10

test- localisation (where is the lesion)

Answer 10

measure ACTH if independent it will be low if dependent (pituitary/ectopic) then will be high. CT/MRI, CXR, octreotide scan, venous samplings (petrosal veins)

Question 11

if ACTH is detectable do a high dose suppression test or a CR hormone test what will happen to cortisol in pituitary disease

Answer 11

cortisol incr with pituitary disease but not with ectopic production

Question 12

what does untreated Cushings lead to

Answer 12

increased vascular mortality