RESUMO
Most sodium disturbances in patients with CNS lesions result from disturbed water regulation. Possible systemic and iatrogenic causes must be evaluated prior to treatment. Insufficient secretion of ADH leads to hypernatremia if fluid intake is inadequate and can be treated with either fluid or hormone replacement. Care must be exercised in patients with acute diabetes insipidus because of the potentially variable and transient nature of the disturbance. Hyponatremia usually results from inappropriate secretion of ADH and should be managed aggressively in symptomatic patients with loop diuretics and hypertonic saline. However, very rapid correction or overcorrection should be avoided. Patients with SAH and hyponatremia should not be fluid restricted because of the risk of exacerbating vasospasm but treated with large volumes of isotonic or mildly hypertonic saline.