hypernatremiaa

Hypernatremia, a condition characterized by an elevated serum sodium concentration, is sometimes encountered under the misspelled term hypernatremiaa. A normal serum sodium range is about 135-145 mEq/L; hypernatremia is defined as a value above 145 mEq/L and reflects a free water deficit relative to body sodium. It can result from insufficient water intake, excessive water loss, or excessive sodium administration, and it is more common in the elderly and in hospitalized patients.

Common causes include dehydration from fever, sweating, diarrhea, or vomiting; diabetes insipidus (central or nephrogenic); osmotic diuresis from hyperglycemia or certain drugs; and iatrogenic administration of hypertonic saline or sodium bicarbonate. Hypernatremia is categorized by volume status into hypovolemic, euvolemic, and hypervolemic forms, which helps guide evaluation and management.

Pathophysiology centers on increased serum osmolality from water deficit, causing cellular dehydration, particularly in brain cells. The brain adapts over time by losing osmolytes, which influences the risk of neurologic complications during correction. Rapid shifts in osmolality during treatment can lead to cerebral edema or other neurologic injury, so gradual correction is emphasized.

Clinical features range from thirst and altered mental status to confusion, seizures, or coma, depending on the degree and rapidity of onset. Diagnosis relies on serum sodium measurement and assessment of volume status, urine osmolality, and urine output to identify the underlying cause.

Management targets the underlying cause and the free water deficit. Initial resuscitation with isotonic fluids may be needed if hypovolemia is present, followed by careful administration of hypotonic fluids to gradually reduce serum sodium. A common goal is to decrease sodium by no more than about 10-12 mEq/L in the first 24 hours, with slower correction thereafter. Prognosis depends on etiology, duration, and comorbidity.