Hypernatremia

Background

• High = >150meq/L
• High! = (Osm >350)

• Usually 2/2 decreased TBW

Diagnosis

• Symptoms
  • 350-375
    • Restlessness, irritability
  • >375-400
    • Tremulousness, Ataxia
  • 400-430
    • Hyperreflexia, twitching, spasticity
  • >430
    • Seizure, coma, death

DDX

1. H2O loss
   1. Decreased Intake
   2. H2O loss > Na loss
      1. vomit
      2. diarrhea
      3. sweating
      4. dialysis
      5. osmotic diuresis
      6. Central DI
         1. Head Trauma
         2. CVA
         3. Tumor
         4. Infect
      7. Nephrogenic DI
      8. Thyroidtoxicosis
2. Na gain
   1. Increased Intake
      1. Na intake
      2. NaBicarb
   2. Renal Na retention
      1. (2nd poor perfusion)

Treatment

1. NS until perfusion deficits corrected
   1. Then switch to 1/2NS until UOP = >0.5 mL/kg/hr

• Avoid lowering Na more than 10-15meq/L/day

• Central DI --> Tx with DDAVP
• Peds: >180meq/L consider peritoneal dialysis

Water Deficit

• Free water deficit = (0.6 x wt in kg) x [(serum Na/140) – 1]

• Each liter H2O Deficit increases Na by 3-5 meq/L

See Also

• Electrolyte Abnormalities (Main)
• MDCalc: www.mdcalc.com/free-water-deficit-in-hypernatremia

Source

Tintinalli