Hypernatremia

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Background

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

Clinical Features

Osm Symptoms
350-375 Restlessness, irritability
376-400 Tremulousness, ataxia
400-430 Hyperreflexia, twitching, spasticity
>430 Seizure, coma, death

Causes of Hypernatremia

Usually secondary to decreased Total Body Water

Hypernatremia

Water loss:

Sodium gain:

  • Increased intake
    • Na intake
    • NaBicarb
  • Renal Na retention (secondary to poor perfusion)

Evaluation

Hypernatremia - New Page.jpeg
  • Elevated sodium on chemistry

Management

  • Normal saline until perfusion deficits corrected
    • Then switch to 1/2NS until UOP = >0.5 mL/kg/hr
    • Target 0.5 mEq/hr correction

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

  • Central DI → Treat 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

Disposition

  • Tailor to underlying cause and severity

Complications

  • Seizures
  • Brain edema if corrected too quickly
  • Brain shrinkage leading to cerebral vessel traction:
    • Venous congestion, thrombosis of venous sinuses
    • Arterial stretching leading to hemorrhage/infarction

See Also

References