First, the liver enlarges, due to a buildup of excess fat, and loses its ability to properly metabolize body substances. This in turn causes the brain to swell, and the pressure of the fluid around the brain increases. Reye's syndrome usually occurs after an upper respiratory tract infection like the flu or chicken pox in children anywhere from infancy to age 19. The child appears to be recovering from the flu or the chicken pox when these new Reye's syndrome symptoms may develop. If you suspect a child has Reye's syndrome, get emergency medical help immediately.
Treatment focuses on reducing brain swelling.
One thing doctors do know about Reye's syndrome is that it seems to be associated with the use of aspirin in those children with the flu or chicken pox. So doctors strongly recommend against giving aspirin to anyone younger than 19 years old during an episode of chicken pox or influenza. Acetaminophen should be substituted, or give no drugs at all.