Reye's syndrome in infancy.

Reye's syndrome in infancy is not a well-defined entity and is infrequently diagnosed. Eight infants 6 months of age or younger had a prodromal viral illness followed by the rapid onset of lethargy, seizures, and coma, resulting in the diagnosis of Reye's syndrome. All had abnormal results of liver function tests including elevations of blood ammonia level. Three patients had pathological studies that confirmed fatty visceral infiltration. The data on these patients, as well as a review of the literature, indicate that the most prominent clinical findings in Reye's syndrome in infancy include marked respiratory abnormalities with tachypnea and apneic episodes; frequent occurrence of seizures in the early stages of the illness; and hypoglycemia in most cases. A strong socioeconomic bias was noted in these patients, with the infants coming primarily from lower socioeconomic, urban environments, while older children with Reye's syndrome have been observed to be predominantly middle-class and from suburban or rural areas.