Hyponatremia: focus on therapy.

Hyponatremia can be a serious medical problem, and severe hyponatremia can be a medical emergency. Nevertheless, considerable controversy remains with respect to the best way to avoid the important sequelae of hyponatremia, while minimizing the complications of its treatment. Unquestionably, severe hyponatremia may cause life-threatening and/or permanent neurologic abnormalities. The risk of these untoward events, however, is much greater with acute than with chronic hyponatremia. The adaptive changes in the brain that reduce the hazards of a low serum sodium concentration for patients with chronic hyponatremia increase the risk for therapy-induced central pontine myelinolysis. In general, acute, symptomatic hyponatremia should be corrected more rapidly than chronic hyponatremia, at least until severe symptoms abate. Detailed guidelines are provided for the management of acute and chronic hyponatremia. But regardless of guidelines, therapy must be individualized, with adjustments based on frequent assessments of clinical condition and laboratory data.