Cushing's Syndrome

Question 1

what is cushing’s syndrome?

Answer 1

an excess of cortisol

Question 2

what is cushing’s disease?

Answer 2

its an excess of cortisol due to an ACTH-secreting tumour

most commonly a pituitary adenoma

Question 3

what are etiologies for cushings?

Answer 3

ACTH-dependant
1. pituitary adenoma
2. ectopic ACTH tumour ➔ small cell lung carcinoma

acth-indpendant
1. exogenous
2. congenial adrenal hyperplasia
3. primary adrenalcortical tumour
4. bilateral adrenal nodular hyperplasia

Question 4

how does cushings cause purple ado striae, osteoporosis, and poor wound healing/easy bruising?

Answer 4

cortisol allows for increased catabolism of proteins and decreases collagen synthesis

so increased catabolism ➔ osteoporosis

impacted collagen ➔ striae and poor wound healing/easy bruising

Question 5

what impact does cushings have on the kidneys? and s/s of it

Answer 5

cortisol has some mineralocorticoid properties and can act as aldosterone

this can lead to HTN and hypokalemia bc increased sodium retention and increased potassium excretion

hypokal ➔ arrythmias, paralysis, and cramps

Question 6

how does cushings impact the reproductive system? s/s

Answer 6

cortisol is a negative feedback inhibitor on the hypothalamus and also decreases the amount of gonadotropin releasing hormone ➔ less estrogen and testosterone

decreased fertility
impacted menses
decreased libido

Question 7

how does cushings impact adipose tissues? s/s

Answer 7

increased selective lipolysis at the peripherals

not in central, or face, or dorsal fat areas

moon facies, buffalo hump, central obesity

Question 8

what impact does cushings have on muscles?

Answer 8

cortisol results in increased muscle break down

weakness, and cardiomyopathy

Question 9

how does cushings impact the immune system?

Answer 9

cortisol suppresses the immune system

so more susceptible to infections

Question 10

how does cushings impact bone and calcium?

Answer 10

cortisol increases osteoclast activity so more bone break down

may result in osteoporosis
may present with fractures

Question 11

in ACTH dependant cushings, what non cortisol related s/s may you see and why?

Answer 11

acne and hirtuism in female pts

because ACTH may also stimulate more androgens from the adrenal

Question 12

why can you get hyperpigmentation in ACTH-dependant cushings?

Answer 12

because melanocyte-stimulating hormone is produced at the same time as ACTH

Question 13

what diagnostic ix would you do to work up cushings vs rule out a low sus cushings?

Answer 13

r/o: serum cortisol

w/u
do 1 of the 3, and repeat it to confirm results
1. dex suppression test ➔ measuring cortisol, cortisol should be depressed if normal
2. 24h urine cortisol
3. midnight salivary cortisol levels

after
1. ACTH levels
2. work up to determine the cause
- imaging of adrenal or pituitary glands
- imaging for ectopic tumours, CT chest, abdo, pelvis

Question 14

what other ix would we do that wouldn’t be diagnostic for cushings?

Answer 14

1. preg test
2. serum glucose ➔ pt may have increased blood sugar bc increased cortisol
3. serum aldosterone and DHEA if thinking adrenal issue
4. CBC and electrolytes

Question 15

what tx would you consider for cushings?

Answer 15

1. surgery to remove tumour
2. could consider rads even for benign
3. treat cancer if maligant

medicinal therapy
1. somatostatin analogue
2. dopamine agonist
3. steroidogenesis inhibitor
4. glucocorticoid receptor antagonist