hyponatremia objectives

Question 1

what are common causes of severe hyponatremia

SHRIMB

Answer 1

1 SIADH

2. Hyperglycemia
3. renal disease
4. intake of water
5. multiple myeloma
6. burns

Question 2

what is pseudohyponatremia?

Answer 2

when sodium free lipid and protein displace sodium rich serum water

Question 3

what are the most common causes of hypertonic hyponatremia

Answer 3

hyperglycemia; causes water to move from ICF to ECF, dehydrating cells

Question 4

what is the only thing that changes in isovolemi hyponatremia, vs. hypovolemic hyponatremia, and hypervolemic hyponatremia?

Answer 4

the plasma osmolality;
high osmolality in hypovolemic
normal osmolality in isovolemic
low osmolality in hypervolemic

Question 5

what happens if hypovolemia is corrected too quickly?

Answer 5

osmotic demyelination leading to brain damage

Question 6

What is done in all cases of hypovolemic hypotonic hyponatremia?

Answer 6

restrict fluid to 1 liter daily

Question 7

how is acute hypovolemic hypotonic hyponatremia treated?

what should be monitored?

Answer 7

1. restrict fluids
2. give 2mEq/L/Hr of 3% Na until Na reaches 125 mEQ/L
   - no more than 10 mEq/L/day
   - monitor serum sodium and neurologic symptoms

Question 8

How is chronic hypovolemic hypotonic hyponatremia with MILD symptoms treated?

Answer 8

1. restrict fluid to 1L/day
2. 0.5mEq/L/hr of 0.9% saline
   - no more than 12 mEq/L/day
   - monitor serum sodium and neurologic symptoms

Question 9

How is chronic hypovolemic hypotonic hyponatremia with severe symptoms treated?

Answer 9

1. restrict fluid to 1L/day
2. 1-1.5mEq/L/hr NS until asymptomatic
   - no more than12mEq/L on first day, no more than 6/mEq/L/day after
3. use 3% saline and loop diuretic with severe symptoms still present
   - monitor serum sodium and neurologic symptoms

Question 10

What is the treatment for SIADH if life threatening or acute?

Answer 10

1. 3% saline and IV furosemide to raise serum Na by 1-2 mEq/L/hour until life threatening symptoms resolve
2. reduce rate
   - don’t currect by more than 8-10 mEq/L in a day

Question 11

What is the treatment for SIADH if moderate symptoms of unkown duration

Answer 11

1. NS with furosemide at 0.5-1 mEq/L/hour
   - no more than 8-10 mEq/L in 24 hours
2. possibly use conivaptin (IV vasopressin antagonist ) but watch for hypotension (nonselective)

Question 12

What is the treatment for SIADH if it is asymptomatic with chronic hyponatremia

Answer 12

1. discontinue causative agent
2. fluid restriction of less than 1L/day
3. Demeclocycline

Question 13

what is the dose and onset time for demeclocycline?

Answer 13

600-1200 mg daily

1-2 weeks to take effect

Question 14

What is the 3 causes of hypervolemic hypotonic hyponatremia

Answer 14

1. CHF
2. Cirrhosis
3. Nephrotic syndrome

Question 15

How is hypervolemic hypotonic hyponatremia due to CHF treated?

Answer 15

1. water restriction
2. low Na diet of less than 2 g per day
3. ACE inhibitor
4. possibly Tolvaptan

Question 16

How is hypervolemic hypotonic hyponatremia due to Cirrhosis treated?

Answer 16

if serum Na < 120, fluid restriction

2. demeclocycline
   - monitor for nephrotoxicity of demeclocycline

Question 17

How is hypervolemic hypotonic hyponatremia resulting in nephrotic syndrome

Answer 17

use an ace inhibitor