Reye syndrome is sudden (acute) brain damage (encephalopathy) and liver function problems of unknown cause. The syndrome has been associated with the use of aspirin to treat chickenpox or the flu in children.
Reye syndrome is most often seen in children from 4 to 12 years old. Most cases associated with chicken pox have been shown to occur in children age 5 to 9, while those associated with the flu (influenzae type B) have occurred in children aged 10 to 14.
Children with Reye syndrome get sick very suddenly. Typically, Reye syndrome follows an upper respiratory infection (URI) or chickenpox by about 1 week. It frequently begins with vomiting, which is persistent over many hours.
The vomiting is rapidly followed by irritable and combative behavior. As the condition gets worse, the child may have problems with their alert (conscious) level). Untreated, seizures and coma may develop, which can quickly lead to death.