Axonal neuropathy in eosinophilia-myalgia syndrome

Three patients with eosinophilia-myalgia syndrome linked to consumption of L-tryptophan supplement developed a severe sensorimotor axonal neuropathy. All three had myalgia, elevated eosinophil count, and later developed fasciitis. Neuropathy was found at all stages of the illness and resulted in disability which was irreversible despite cessation of L-tryptophan. Nerve conduction studies showed reduced motor and sensory evoked response amplitudes with select sparing of some nerves and the arms were more involved than the legs. Cerebrospinal fluid protein content was increased in one of two patients so tested. Creatine kinase was normal and muscle biopsy showed perimysial inflammation. Sural nerve biopsy in one case showed epineural perivascular inflammation. Our data showed that a severe sensorimotor axonal neuropathy occurs in eosinophilia-myalgia syndrome, suggestive of mononeuritis multiplex.