Hypernatremia

• • High serum sodium

  • Caused by either a loss of water or a gain of hypertonic saline

Epidemiology

• • Typically accompanies dehydration/water loss in perioperative or post-trauma patients

  • Pure water loss

  • -Unreplaced insensible water losses

    -Hypodipsia

    -Neurogenic diabetes insipidus

    -Congenital diabetes insipidus

    -Acquired nephrogenic diabetes insipidus (renal disease, hypercalcemia, hypokalemia, drugs including lithium and amphotericin B)

  • Hypotonic fluid loss

  • -Renal losses (due to loop diuretics, osmotic diuretics, postobstructive diuresis, polyuric acute tubular necrosis)

    -GI losses (vomiting, NG drainage, enterocutaneous fistula, diarrhea, osmotic cathartic agents)

    -Cutaneous losses (burns, excessive sweating)

  • Hypertonic sodium gain

  • -Hypertonic sodium bicarbonate infusion

    -Hypertonic feeding solution

    -Sodium chloride ingestion

    -Sea water ingestion/drowning

    -Hypertonic sodium chloride infusion, enemas, intrauterine injection, or dialysate

    -Primary hyperaldosteronism

    -Cushing syndrome

Symptoms and Signs

• • CNS dysfunction; may be very hard to demonstrate in a person with coexisting illness

  • -More prominent symptoms with rapid changes in sodium level

  • Thirst early, which resolves as hypernatremia becomes more severe

Laboratory Findings

• • High serum sodium

• • Must determine intravascular volume status to guide resuscitation

• • Serum electrolytes

• • Water replacement and/or sodium restriction

  • Change serum sodium no more than 1-2 mEq/L/h

  • -More rapid changes risk iatrogenic cerebral edema

Treatment Monitoring

• • Serum electrolytes

Complications

• • Permanent brain damage

Prognosis

• • Excellent

Prevention

• • Judicious IV administration and monitoring of volume status

References