Hyponatremia in the neurosurgical patient: Epidemiology, pathophysiology, diagnosis, and management

OBJECTIVE: Hyponatremia is an important and common electrolyte disorder in critically ill neurosurgical patients that has been reported in association with a number of different primary diagnoses. The correct diagnosis of the pathophysiological cause is vital because it dramatically alters the treatment approach. METHODS: We review the epidemiology and presentation of patients with hyponatremia, the pathophysiology of the disorder with respect to sodium and fluid balance, and the diagnostic procedures for determining the correct cause. RESULTS: We then present the various treatment options, including discussion of one of the newest groups of agents, the arginine vasopressin receptor antagonists, currently under study for the treatment of hyponatremia in neurosurgical patients. CONCLUSION: Hyponatremia is a serious comorbidity in neurosurgical patients that requires particular attention as its treatment varies by cause and its consequences can affect neurological outcome.