In Reply.—We welcome the report by Dr Savasta et al of two infants with hemorrhagic shock and encephalopathy (HSE) from Italy for two reasons: (1) it provides useful epidemiologic information about the occurrence of HSE outside the United States and Great Britain, and (2) it emphasizes the predilection for HSE development in infants. Although HSE may occur in older children, as reported by Levin et al1 and others2 (and also as seen by us at Children's Hospital of the King's Daughters), the mechanism may be different from that postulated for HSE occurring in infancy. The similarities between HSE and heatstroke in infants suggest that hyperthermia may be an important precipitating factor, with consequent damage to the vascular endothelium. Because this vulnerability probably decreases after infancy, the pathophysiologic development of HSE in older children may be different. For this reason, we included only cases of HSE in infants