SIADH vs DI

Question 1

SIADH is due to inappropriate what?

Answer 1

Water Retention

Question 2

Nephrogenic DI can be acquired due to?

Answer 2

Pyelonephritis

Question 3

Signs/Symptoms of SIADH

Answer 3

Neurologic Changes from hyponatremia: mild HA, Seizures, coma
Decreased DTRs
hypothermia
weight gain/edema
nausea/vomiting
cold intolerance
/

Question 4

Signs/Symptoms of DI

Answer 4

Thirst/cravings for water (fluid intake 5-20 L/day)
Polyuria (2-20 L/day)
weight loss, fatigue
Changes in LOC
Dizziness
Elevated temp
tachycardia
hypotension
poor turgor and dry mucus membranes

Question 5

Lab/Diagnostics of SIADH

Answer 5

Hyponatremia (yet euvolemic)
Decreased serum osmolality (< 280 mOsm/kg)
Increased urine osmolality (> 100 mOsm/kg)
Urine sodium > 20 mEq/L
Normal renal, CV, and thyroid fxn

Question 6

Lab/Diagnostics of DI

Answer 6

Hypernatremia
Elevated BUN/Creatinine
Serum Osmolality > 290 mOsm/kg
Urine Osmolality < 300 mOsm/kg
Urine SG < 1.005

Question 7

If Central DI is suspected perform what test?
How is it done?

Answer 7

Vasopressin challenge test
0.05-0.1 ml nasally or 1ug SQ or IV w/ measurement of urine volume

Question 8

Management of SIADH
1. Treat the?
2. If serum Na+ is > 120 mEq/L, treat how?
3. If serum Na+ is 110-120 mEq/L w/o neuro symptoms , treat how?
4. If Serum Na+ is < 110 mEq/L or neuro symptoms are present, treat how?

Answer 8

1. underlying cause
2. restrict total fluids to 1000 ml/24 hr and monitor
3. restrict fluids to 500 ml/24 hrs and monitor
4. replace with isotonic or hypertonic saline and furosemide at 1-2 mEq/h. Monitor Na+K+ losses hourly and replace.

Question 9

Management of DI
1. If serum Na+ > 150, give what?
2. When Na+ < 150, do what?
3. Give what for acute situations?
4. Maintenance dose of what is given how often and by what route?

Answer 9

1. D5W IV to replace 1/2 volume deficit w/n 12-24 hrs
2. Substitute fluids for 1/2 NS or 0.9 NS
3. DDAVP 1-4mcg IV or SubQ q12-24 hrs
4. DDAVP 10 ug q 12-24 hrs intranasally