Transient exercise-induced water intoxication and rhabdomyolysis.

Water loading only rarely results in adverse effects due to the high efficiency of the kidney in excreting free water. However, when renal diluting ability is impaired, such as in inappropriate vasopressin secretion, water intoxication can occur in otherwise normal individuals. We report the case of a 19-year-old man with acute voluntary water intoxication following exercise, which resulted in a transient defect in renal diluting capability. Hyponatremia was further complicated by rhabdomyolysis. We review the literature regarding other cases of hyponatremia following excessive water intake, and discuss the possible association between hyponatremia and rhabdomyolysis. We conclude that monitoring of muscle enzymes is indicated in acute hyponatremia, to allow for timely intervention intended to prevent rhabdomyolysis-associated acute renal failure.