Eosinophilia-myalgia syndrome: the Cleveland Clinic experience

Eosinophilia-myalgia syndrome is a recently described clinical syndrome caused by a suspected contaminant of L-tryptophan, an essential amino acid that was manufactured and sold as a nutritional supplement. This study reports the clinical and pathological findings of 22 cases of eosinophilia-myalgia syndrome evaluated at the Cleveland Clinic and includes data for up to 1 year of follow-up (for the epidemic cases). Nineteen of the 22 cases were evaluated and followed prospectively in the time period from November 1989 to November 1990. Two of the 22 represented nonepidemic forms of the syndrome which occurred prior to the 1989 epidemic. During a review of all cases of biopsy-proven diffuse fasciitis with eosinophilia at the Cleveland Clinic since 1978, one of the 22 was retrospectively identified as having an epidemic form of the syndrome, with onset in July 1989. In this study, adverse prognosticating factors in eosinophilia-myalgia syndrome included nerve and muscle involvement, fasciitis, and weight loss. Eosinophilia-myalgia syndrome is striking in its severity and diversity, and its features are similar to those of two other unusual illnesses--toxic oil syndrome and diffuse fasciitis with eosinophilia. With the recent purification of the suspected contaminant, it is hoped that further clues to the etiology of this syndrome and similar syndromes will be uncovered.