The clinical presentation includes shock, coma and/or seizure, hemorrhage, diarrhea, and oliguria. Laboratory investigations reveal decreased hemoglobin and platelet counts, evidence of DIC, elevated creatinine, AST and ALT, and metabolic acidosis. However, when patients met the HSES criteria, their condition was always critical with multiple organ failure. We determined that these HSES In these cases, the first problem the physician is faced with is the difficulty of the differential diagnosis. Some reports have indicated in the differential diagnosis the diseases of the toxic shock syndrome, the hemolytic-uremic syndrome, and Reye's syndrome, among others [6] [7] [8] . In our patients, those diseases were excluded because of the lack of skin or mucosal manifestations, hemolysis, and/or blood ammonia levels. The clinical course of our patients was not indicative of any of these diseases. Heatstroke has similar clinical and pathological features to HSES; however, there was no history of over wrapping or excessive heating in any of our patients in the present study.