Diagnostic criteria for influenza B-associated Reye's syndrome: clinical vs. pathologic criteria.

Between December 15, 1973, and Jun 30, 1974, a total of 379 cases of Reye's syndrome was reported to the Center for Disease Control. One hundred forty-seven (40%) were confirmed by either autopsy or biopsy, while 232 were diagnosed by clinical and laboratory parameters. Comparisons of the epidemiologic and demographic characteristics, the hospital course, the outcome, and the laboratory abnormalities of the clinically diagnosed and the pathologically confirmed cases revealed no significant differences. In the epidemiologic setting of influenza B outbreaks, children who have the acute onset of noninflammatory encephalopathy associated with elevated serum transaminase levels, hypoprothrombinemia, and elevated blood ammonia levels should be considered to have Reye's syndrome. Further evaluation of diagnostic criteria is needed, however, for sporadically occurring, nonepidemic cases of noninflammatory encephalopathy associated with hepatic dysfunction.