What are the clinical manifestations of hypernatremia?
In an otherwise healthy individual, hypernatremia manifests as thirst, which prompts increased electrolyte-free water intake and serum sodium concentration normalization. Thirst can dissipate, however, as hypernatremia worsens. Thirst aside, patients otherwise are typically asymptomatic until the serum sodium rises to near 160 mEq/L. In more severe cases, hypernatremia-induced brain shrinkage can lead to vascular tension and rupture with intracranial hemorrhage. Infants and children are at particular risk for this devastating complication. While lethargy, coma, and muscle weakness are associated with hypernatremia, such symptoms are often manifestations of other comorbidities as opposed to the hypernatremia itself. Note that while clinicians oftentimes refer to hypovolemic patients as being “dehydrated,” when used rigorously, the term “dehydration” is reserved for hypernatremic patients, who demonstrate a true deficit of electrolyte-free water relative to sodium.
