Fludrocortisone in the treatment of subarachnoid hemorrhage-induced hyponatremia.

Hyponatremia, natriuresis, and a decrease in plasma volume of greater than 10% occurs in approximately 50% of the patients with aneurysmal SAH, perhaps due to SIADH and CSWS. However, fluid restriction, as indicated in SIADH, might result in vasospasm and cerebral infarction in these patients. Maintaining intravascular volume seems to be important in SAH; several reports suggest that cerebral ischemia can be reversed by use of volume expanders. Fludrocortisone has been shown to reduce natriuresis, which may help maintain plasma volume in patients with SAH. Adequate oral salt intake also appears to have possible therapeutic benefit in these patients. However, it remains unproven whether fludrocortisone results in a decreased incidence of cerebral ischemia. Larger controlled trials are needed to ascertain the impact of fludrocortisone on prevention of cerebral ischemia in patients with SAH.