Renal failure and heatstroke.

We report a fatal case of heatstroke in an obese boy who developed multi-organ failure. Six other cases of exertional heatstroke admitted to our hospital over the last 5 years were also reviewed. All of them showed some degree of renal impairment. The causes of renal failure are multifactorial, with rhabdomyolysis being the major mechanism. All cases except one responded to alkaline diuresis without the need for dialysis. Continuous venovenous hemofiltration appeared to be a good alternative in hemodynamically unstable patients. Renal function recovered completely after varying intervals in all surviving cases. Interestingly, rhabdomyolysis in our heatstroke patients was usually associated with hypokalemia or normokalemia instead of hyperkalemia. Mortality in our series was largely related to the long duration of hyperthermia and coma, the severity of disseminated intravascular coagulation, and the presence of cardiogenic shock and severe acidosis.