Bone Disease as a New Complication of Hyponatremia

Abstract

Brain injury is the main result of acute symptomatic hyponatremia, and it is associated with significant morbidity and mortality (1,2). The symptoms of hyponatremic encephalopathy primarily result from cerebral edema, which is caused by an influx of water into the brain down a concentration gradient (2). Patients at high risk for this complication include postoperative patients, young female individuals, children, and patients with hypoxia or central nervous system disease (1–3); however, although the brain seems to be the main target for hyponatremia, it can no longer be considered the only organ affected by this condition. Recent information indicates that the systemic effects of hyponatremia also affect other organs. Lung abnormalities, such as respiratory failure as a consequence of hyponatremic encephalopathy, have been described (4). One distinct aspect of this condition is the so-called Ayus-Arieff syndrome: A form of noncardiogenic pulmonary edema secondary to increased intracranial pressure from cerebral edema (5–7). Can bone abnormalities be a consequence of hyponatremia? In 1999, our group noted that for a large percentage of elderly women, orthopedic injury was the presenting manifestation of hyponatremic encephalopathy (8). It has subsequently been confirmed that mild chronic hyponatremia, mean serum sodium (SNa) 128 mEq/L, in adults can result …