Mtb: Endocrinology 8, Adrenal Disorders

Front 1

disease of pituitary overproduction of ACTH

Back 1

Cushing disease

Front 2

otherwise it can be broadly called

Back 2

Cushing SYNDROME if it's due to ectopic production of ACTH, prednisone use etc.

Front 3

what is the most common cause of Cushing syndrome

Back 3

Cushing DISEASE due to overproduction of ACTH`

Front 4

some signs of Cushing syndrome

Back 4

moon face, buffalo hump, truncal obesity, thin extremities

striae, easy bruising, thin skin

osteoporosis

HTN

menstrual disorders, erectile dysfunction

psychosis, cognitive dysfunction

polyuria

Front 5

best initial test for presentation of Cushing's

Back 5

24 urine cortisol

Front 6

Then what comes afterward?

Back 6

1 mg overnight dexamethasone suppression testing

Front 7

And what is the purpose of the low dose dexa test?

Back 7

it's done to EXCLUDE a dx of Cushing's. If you suppress at low dose then you do NOT have hypercortisolism

Front 8

And what is the limitation of the low dose dex?

Back 8

there are quite a few false positives

Front 9

So in other words, 24 hour urine cort is more

Back 9

specific. you can confirm a dx of hypercortisolism with urine levels

Front 10

What is the next step in workup of Cushing if you have elevated 24 hour urine cort

Back 10

then you need to LOCALIZE the cause through ACTH testing

Front 11

If the ACTH level is elevated...

Back 11

then it's either pituitary in origin or it's from ectopic production

Front 12

If the ACTH level is suppressed.

Back 12

it's likely an adrenal adenoma`

Front 13

If the ACTH level is elevated, the next test to perform is...

Back 13

a high dose dexa suppression test

Front 14

and how do you interpret the high dose dexa test?

Back 14

if ACTH SUPPRESSES with high dose dexa, then it's likely in the pituitary

If it DOESN'T suppress then it's likely an ectopic source like a lung cancer or carcinoid

Front 15

If the ACTH suppresses, and you suspect a pituitary origin you would next

Back 15

get an MRI of the brain

Front 16

If the MRI is still negative, what can you do?

Back 16

you can do a sample of the petrosal sinus for ACTH levels. some adenomas are too small to be picked up on MRI

Front 17

If the high dose dexa test does NOT suppress and you suspect an ectopic souce, what is the next best step?

Back 17

you should do a chest X ray

Front 18

Why do we avoid doing an MRI of the head for so long?

Back 18

because 10% of the population will show an abnormality on MRI in the pituitary. so it's totally non-specific. the high dose dexa test is much more specific

Front 19

What is cortisol's effect on blood sugar?

Back 19

it's anti-insulin so it raises it

Front 20

What is the effect on the kidney?

Back 20

it has some activity on the mineralocorticoid receptor and stimulates Na+ retention and K+ wasting

Front 21

Why is WBC high in hypercort?

Back 21

because of demargination

Front 22

laboratory findings associated with hypercortisolism

Back 22

hyperglcyemia

hyperlipidemia

hypokalemia

metabolic alkalosis

Front 23

what is the treatment for hypercortisolism?

Back 23

surgically remove the source- whether adrenal, ectopic or pituitary

Front 24

What si the workup for an adrenal incidentaloma?

Back 24

it's fairly conservative but you want to rule out subclinical disorders:

get urine or blood metanephrines to exclude pheo

get renin and aldo levels to exclude Conn

perform a 1 mg dexamethasone suppression test

Front 25

chronic hypoadrenalism is also called

Back 25

Addison disease

Front 26

acute hypoadrenalism is called

Back 26

adrenal crisis

Front 27

most common cause for Addison "syndrome"

Back 27

autoimmune destruction of the glands in 80% of cases

Front 28

some other causes

Back 28

TB

adrenoleukodystrophy

metastasis of the adrenal gland (SCLC loves the adrenals)

Front 29

what would cause an adrenal crisis?

Back 29

think hemorrhage- surgery, hypotension, trauma

anything that results in rapid destruction of the gland

Front 30

another iatrogenic cause for adrenal crisis

Back 30

sudden withdrawal of exogenous steroid like prednisone- you have to taper

Front 31

some presenting sxs of Addison

Back 31

weakness, fatigue

altered mental status

N/V

anorexia

hypotension

hyponatremia

hyperkalemia

Front 32

so the main lab to remember is

Back 32

HYPERKALEMIA

they don't have aldo

Front 33

acute adrenal crisis is more likely

Back 33

to present with extreme findings like coma, severe hypotension etc.

Front 34

lab values associated with HYPOadrenalism

Back 34

basically just the opposite of Cushing:

HYPERkalemia

hypoglycemia

hypotension

metabolic acidosis

hyponatremia

Front 35

How do we localize hypoadrenalism?

Back 35

through interpretation of the ACTH level:

low ACTH= pituitary gland lesion

high ACTH= probably an adrenal crisis of some sort

Front 36

main diagnostic modality for Addison is`

Back 36

cosyntropin stim test

Front 37

and what does this tell you?

Back 37

whether the adrenal gland is able to mount a response to ACTH or not.

Front 38

what is the treatment for hypoadrenalism?

Back 38

need to give hydrocortisone

Front 39

what is given to replace mineralocorticoid?

Back 39

fludrocortisone

Front 40

and what ist he main clinical utility of fludrocortisone/

Back 40

mostly used to treat postural hypotension

Front 41

if a patient presents with all signs and symptoms of an acute adrenal crisis how should you manage them?

Back 41

diagnostics become much less important acutely- you need to just draw a cort level and give hydrocortisone replacement