Severe hyponatremia in spinal cord injury.

A male quadriplegic (C6--complete) with persistent chronic hyponatremia (serum sodium values ranging consistently from 117-132 mmol/L) developed acute hyponatremia with a serum sodium concentration of 98 mmol/L. This extreme hyponatremia related, in part, to a reversible defect in the excretion of a water load, while on a low (46 mmol/day) sodium diet. Subsequent ingestion of a normal sodium diet (150 mmol/day), with or without 0.1 mg of fludrocortisone (Florinef), reestablished his ability to excrete a water load normally. The etiology of this patient's hyponatremia is discussed as well as the unique concordance of factors which make hyponatremia a common occurrence among spinal-cord injured patients.