Reye Syndrome : Part 2

by Food and Drug Administration (FDA)

(Page 2 of 2)

The public was quick to pick up on the association. "A kind of natural study was occurring, because once people heard about the results [of the studies], they started to lower the use of aspirin in their children," says Schonberger. "If aspirin had nothing to do with it [Reye syndrome], then one might anticipate that there would be no clear decrease in the incidence of Reye syndrome."

That's not what happened. Aspirin use in children under 10 declined by at least 50 percent from 1981 to 1988, and the number of Reye syndrome cases went down correspondingly. In the opinion of Peter C. Rowe, M.D., assistant professor of pediatrics, Children's Hospital of Eastern Canada, Ottawa, Ontario, the declining use of aspirin and the decreasing incidence of Reye syndrome represent a "natural ecological experiment."

Other Government Actions

The federal government made other moves. To confirm the preliminary findings of the state studies, in 1985-1986 the government sponsored the "Public Health Service Study of Reye's Syndrome and Medications." Twenty-seven children who developed Reye syndrome after a preceding respiratory illness or chicken pox were matched with 140 children who had had the same illnesses at the same time, but did not develop Reye syndrome. More than 96 percent of the Reye syndrome cases, compared with 38 percent of the controls (the children who did not develop Reye syndrome), had received aspirin (or other salicylates) to treat the preceding illness. The study was prematurely ended because not enough Reye syndrome children who had not been exposed to aspirin could be found to justify the expense of continuing the investigation, in itself an indication of a public health triumph.

In 1986, FDA adopted a preliminary rule requiring aspirin manufacturers to add warnings to product labels about the possible association between aspirin use and the development of Reye syndrome. The permanent rule became final in 1988, and the labeling reads: Children and teenagers should not use this medicine for chicken pox or flu symptoms before a doctor is consulted about Reye syndrome, a rare but serious illness reported to be associated with aspirin.

The number of Reye syndrome cases, which reached a high in 1980 with 555 cases, has steadily decreased, compared with years in which there has been similar types of influenza activity. The decline has been most dramatic among children from 5 to 10 years of age. In 1989, a heavy influenza B year, 27 cases of Reye syndrome were reported to CDC, almost half of them fatal. According to CDC, since 1985, 40 to 65 percent of reported Reye syndrome patients have been older than 10. Because this age group often self-medicates, recent educational efforts have been geared to reach them.

Other Factors:

Some questions about the relationship between aspirin and Reye syndrome still remain. Although figures show that 90 to 95 percent of Reye syndrome patients in the United States have taken aspirin during a preceding viral illness, it is estimated that less than 0.1 percent of children having a viral infection and treated with aspirin develop the syndrome. Are other factors involved?

Apparently so. Reye syndrome has always been a puzzling disease. Research on possible causes has been hampered because no one can come up with a simple specific diagnostic test for the syndrome. The waters are further muddied by the existence of at least 19 viruses, including the chicken pox and flu viruses, which cause infectious illnesses that can precede Reye syndrome development. Some experts have proposed that Reye syndrome develops from the interaction of a viral illness, genetic susceptibility to the disease, and exposure to chemicals, such as salicylates, pesticides and aflatoxin. Others speculate that unidentified viruses or other infectious agents are involved.

That some children may be more susceptible to Reye syndrome than others has been shown by cases appearing among children in the same family and by recurrent episodes of the illness in the same child. It is possible that more than one type of Reye syndrome exists, or that some of these cases may not be Reye syndrome at all.

Reye-Like Disorders

In the light of what we know now, it is even questionable whether all pathologist Reye's cases were true Reye syndrome. Recent research indicates that some children diagnosed in the past with Reye syndrome, particularly those under 5, may have had underlying metabolic abnormalities that produce similar symptoms.

"There may well be certain cases that come in even today — in the very young — that five years from now we'll find are really some other abnormal congenital problem — where they have a metabolic defect and it expresses itself in a form that looks very much like Reye syndrome," says CDC's Schonberger. Because these children require different treatment, proper diagnosis can be a matter of life or death. In children 5 or older, the diagnosis of Reye syndrome is more conclusive — especially when symptoms occur during flu and chicken pox epidemics — since few other diseases in this age group mimic common Reye syndrome symptoms.

It's possible that metabolic disorders will prove some day to be the chief cause of Reye syndrome. However, until then, it's important to remember that aspirin use during flu or chicken pox is asking for trouble.

In Schonberger's words: "The association between aspirin and Reye syndrome is so strong that it has now become literally foolhardy to act as if no etiologic [cause-and-effect] relationship exists."

About the Author

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