Management of hyponatremia and volume contraction.

Hyponatremia is the most common electrolyte imbalance seen in patients with aneurysmal subarachnoid hemorrhage, occurring in one-third to one-half of patients. Hyponatremia may be caused by cerebral salt wasting and by the syndrome of inappropriate secretion of antidiuretic hormone or a combination of both. Limited data are available describing hyponatremia treatment in subarachnoid hemorrhage patients. A Medline search was performed for English-language manuscripts describing original research in the treatment for hyponatremia in patients with aneurysmal subarachnoid hemorrhage. Seven appropriate articles were identified as followed: three testing fludrocortisone, two hydrocortisone, and one each for hypertonic saline and 5% albumin. Data quality for treatment efficacy and safety were moderate for corticosteroid studies and low or very low for hypertonic saline and 5% albumin. Available data, although limited, support early treatment with corticosteroids to limit hyponatremia, with fludrocortisone causing fewer side effects.