Hyponatremia and Hypovolemia

To the Editor: In his editorial on the treatment of hyponatremia (April 25 issue),* Dr. Schrier mentions hypovolemia as a stimulus for secretion of antidiuretic hormone. Although this is true of the mechanisms underlying hypersecretion of antidiuretic hormone, it is not appreciated that hypovolemia may actually lead to hyponatremia. We studied five patients with marked hyponatremia, such that all had features of severe neurologic dysfunction, such as epileptiform seizures or loss of consciousness. All had markedly subnormal plasma albumin concentrations (18 to 22 g per liter), associated with hyponatremia. All had normal sodium and albumin concentrations at the time of.