Week 5 - Endocrine

Question 1

How do you calculate an anion gap?

What’s a normal range?

Answer 1

Na - bicarb - Cl

8-12

Question 2

What’s the treatment for DKA?

Answer 2

Fluid bolus

Insulin gtt 0.05-0.1 U/kg/hr

2 bag system: 1.5-2x mIVF NS & D10NS + 20KCl

Question 3

What’s the most worrisome complication of DKA?

Answer 3

Cerebral edema

Question 4

What are some findings that should make you suspect cerebral edema?

Answer 4

Headache
Slowing HR, rising BP
Change in neuro status

Question 5

How would you treat cerebral edema?

Answer 5

3% saline 3-5mL/kg/dose fast push

Alt - mannitol

Question 6

How would you define polydipsia?

Answer 6

Inc thirst

Adults > 5L daily
Children > 2L/m2 daily

Question 7

How would you define polyuria?

Answer 7

Inc dilute urine output

Adults > 3L daily
Children > 2L/m2 daily

Question 8

What condition results from not enough ADH?

What happens to Na levels and urine?

Answer 8

diabetes insipidus

Na high (>150)
UOP high (>3) 
dilute, spec grav < 1.005

Question 9

What condition results from too much ADH?

What happens to Na levels and urine?

Answer 9

SIADH

Na low (<130)
UOP low (<1)
concentrated, spec grav > 1.020

Question 10

Labs:
serum Na < 130
urine Na > 60
serum Osm < 275
urine Osm > 500
spec grav > 1.020
UOP < 1

What condition is this?

Answer 10

SIADH

Question 11

Labs:
serum Na > 150
urine Na < 40
serum Osm > 305
urine Osm < 250
spec grav < 1.005
UOP > 3

What condition is this?

Answer 11

DI

Question 12

Labs:
serum Na < 130
urine Na > 150
serum Osm < 275
urine Osm > 300
spec grav > 1.010
UOP > 3

What condition is this?

Answer 12

cerebral salt wasting

Question 13

SIADH tx?

Answer 13

fluid restriction (1/4-1/2 mIVF)

salt
NaCl 1g 3-4x/day
3% hypertonic saline

Question 14

What’s the purpose of a water deprivation study?

What does water deprivation do to the body?

Answer 14

To test ability of patient to concentrate urine when fluids are withheld.

Water deprivation –> inc ADH –> small volumes of concentrated urine

Question 15

How would you differentiate between central DI and nephrogenic DI during the study?

Answer 15

Give DDAVP if urine Osm < 600 any time during or at the end of the study.

If:
urine Osm 2x over next hour -> cDI
urine Osm no response -> nDI

Question 16

How would you r/o or dx DI during the study?

Answer 16

If urine Osm > 600 during the test, okay to r/o

Urine Osm < 600 = inability to concentrate urine = DI

Question 17

What are the 3 stages of triphasic response?

Answer 17

1. transient DI
2. hyponatremia/SIADH
3. permanent DI

Question 18

What labs would point you to a dx of DKA?

Answer 18

glucose > 250
pH < 7.3
serum bicarb < 15
elevated ketones in serum or urine

Question 19

When would you consider discontinuing insulin gtt during DKA tx?

Answer 19

anion gap reduced to normal (8-12)
pH > 7.3
bicarb > 15
BG < 200
tolerating PO

Question 20

Tx for DI?

cDI vs nDI?

Answer 20

correct Na slowly (decrease shouldn’t be faster than 12mEq/L every 24hrs)

low salt, low protein diet

cDI - DDAVP
nDI - thiazide diuretics (hydrochlorothiazide)