Cerebral Salt-Wasting Syndrome: Diagnosis by Urine Sodium Excretion

CSWS was diagnosed in patients with cerebral lesion who had (1) symptomatic hyponatremia, (2) urine Na excretion 2 standard deviations above controls and (3) increased urine volume. Patients with SIADH also had symptomatic hyponatremia but, in contrast to patients with CSWS, they had decreased Na excretion and urine volume. Thus urine Na excretion and volume are very important for diagnosing the cause of hyponatremia in patients with cerebral lesions.