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Hypernatremia
Aka: Hypernatremia, High serum sodium
- See Also
- Sodium and Water Homeostasis
- Serum Sodium
- Fluid Management in Critical Care
- Definitions
- Hypernatremia
- Serum Sodium exceeds 145 meq/liter
- Epidemiology
- Incidence: 1% of hospitalized elderly patients
- Pathophysiology
- Free water deficient state
- Total Body Water deficit > Total Body Sodium Deficit
- Excess water loss or rarely excess Sodium intake or Sodium retention
- Lacks normal physiologic response to free water loss
- Inability to concentrate urine or inadequate ADH secretion
- Lack of thirst response or inadequate access to free water
- Findings: Signs and Symptoms
- Infants
- Tachypnea
- Muscle Weakness
- Motor restlessness
- High pitched crying
- Lethargy
- Coma
- Adults
- Anorexia
- Nausea or Vomiting
- Muscle Weakness
- Lethargy
- Restlessness
- Hyperreflexia
- Spasticity
- Seizures
- Causes
- See specific types below
- Hypernatremia with Polyuria in hospitalized patients is common
- Results from parenteral or enteral feeds AND
- Inadequate free water intake OR Increased free water loss (e.g. Central Diabetes Insipidus in Head Injury)
- Types: Based on Volume Status
- Hypervolemic Hypernatremia
- Hypernatremia with Increased Total Body Sodium
- Isovolemic Hypernatremia
- Hypernatremia with Normal Total Body Sodium
- Hypovolemic Hypernatremia
- Hypernatremia with Decreased Total Body Sodium
- Labs (Dependent on Hypernatremia subtype as above)
- Serum labs
- Serum Sodium >145 mEq/L
- Severe symptoms occur at >160 mEq/L
- Serum Glucose
- Serum Calcium
- Serum Creatinine and Blood Urea Nitrogen
- Urine labs
- Urine Volume
- Urine Sodium
- Urine Potassium
- Urine Chloride
- Urine Calcium
- Calculations based on above
- Serum Osmolality
- Free Water Deficit
- Serum to urine Electrolyte ratio
- Urine Electrolytes: Urine Sodium + Urine Potassium
- Serum Electrolytes: Serum Sodium + Serum Potassium
- Interpretation (question whether Kidney is excreting or retaining Electrolyte-free water)
- Concentrated urine: Urine Electrolytes exceed serum Electrolytes
- Dilute urine: Serum Electrolytes exceed urine Electrolytes
- Management
- See specific Hypernatremia types based on fluid status
- See Hypervolemic Hypernatremia
- See Isovolemic Hypernatremia
- See Hypovolemic Hypernatremia
- Complications of cerebral dehydration
- Cerebral Hemorrhage
- Subarachnoid Hemorrhage
- Subcortical Hemorrhage
- Venous sinus thrombosis
- Prognosis: Mortality
- Children
- Acute Hypernatremia: 43%
- Chronic Hypernatremia: 7-29%
- Adults
- Acute Hypernatremia: 60%
- References
- Braun (2015) Am Fam Physician 91(5): 299-307 [PubMed]