Reye's syndrome in the United States from 1981 through 1997

Background Reye's syndrome is characterized by encephalopathy and fatty deg eneration of the liver, usually after influenza or varicella. Beginning in 1980, warnings were issued about the use of salicylates in children with th ose viral infections because of the risk of Reye's syndrome. Methods To describe the pattern of Reye's syndrome in the United States, ch aracteristics of the patients, and risk factors for poor outcomes, we analy zed national surveillance data collected from December 1980 through Novembe r 1997. The surveillance system is based on voluntary reporting with the us e of a standard case-report form. Results From December 1980 through November 1997 (surveillance years 1981 t hrough 1997), 1207 cases of Reye's syndrome were reported in patients less than 18 years of age. Among those for whom data on race and sex were availa ble, 93 percent were white and 52 percent were girls. The number of reporte d cases of Reye's syndrome declined sharply after the association of Reye's syndrome with aspirin was reported. After a peak of 555 cases in children reported in 1980, there have been no more than 36 cases per year since 1987 . Antecedent illnesses were reported in 93 percent of the children, and det ectable blood salicylate levels in 82 percent. The overall case fatality ra te was 31 percent. The case fatality rate was highest in children under fiv e years of age (relative risk, 1.8; 95 percent confidence interval, 1.5 to 2.1) and in those with a serum ammonia level above 45 mu g per deciliter (2 6 mu mol per liter) (relative risk, 3.4; 95 percent confidence interval, 1. 9 to 6.2). Conclusions Since 1980, when the association between Reye's syndrome and th e use of aspirin during varicella or influenza-like illness was first repor ted, there has been a sharp decline in the number of infants and children r eported to have Reye's syndrome. Because Reye's syndrome is now very rare, any infant or child suspected of having this disorder should undergo extens ive investigation to rule out the treatable inborn metabolic disorders that can mimic Reye's syndrome. (N Engl J Med 1999;340:1377-82.) (C) 1999, Mass achusetts Medical Society.