Acute symptomatic hyponatremia and cerebral salt wasting after head injury: An important clinical entity

Hyponatremia is a well known complication of traumatic and nontraumatic cer ebral injury, often related to the syndrome of inappropriate antidiuretic h ormone secretion (SIADH). Nonetheless, it also can be associated with a dif ferent entity, the syndrome of cerebral salt wasting (CSW). The authors rep ort the case of a 4.5-year-old boy presenting with major head injury who at day 6 after admission had generalized tonic-clonic seizures caused by seve re acute hyponatremia (serum sodium level, 119 mmol/L) and signs of dehydra tion. Despite initial isotonic rehydration, hyponatremia persisted because of excessive renal salt losses and concomittant enormeous water losses, nec essitating increasing amounts of sodium, up to 160 mmol/kg/d, and large amo unts of intravenous fluids, up to 27 L/d. Highly increased levels of atrial natriuretic peptide (ANP) confirmed the diagnosis of CSW. The occurence of a CSW has to be recognized early in the clinical course for adequate treat ment and remains one of the important differential diagnosis of SIADH in hy ponatremic states in patients with cerebral disorders, especially after hea d injury. Copyright (C) 2001 by W.B. Saunders Company.