Multifocal neuropathy with vasculitis in hypereosinophilic syndrome. An entity or drug-induced effect?

A 56-year-old male with a 2-year history of bronchial asthma, together with pulmonary infiltration and marked eosinophilia, developed a subacute multifocal sensorimotor neuropathy. Electrodiagnostic studies demonstrated both multifocal and generalized nerve involvement. Sural nerve and muscle biopsies revealed axonal degeneration with almost complete loss of myelinated fibres, lymphomononuclear vasculitis of interstitial vasa nervorum without eosinophils, and neurogenic atrophy of muscle without angiitis. Although eosinophilia decreased drastically with corticosteroid treatment, neuropathy rapidly progressed to total disability. The patient died from pulmonary embolism 4 months after the onset of neurological signs. Autopsy disclosed vasculitis of epineurial vessels of peripheral nerves and severe axonal neuropathy, particularly of the lower limbs, without vasculitis or other inflammatory lesions in any other organ system, including the lungs. Retrospective analysis revealed that the onset of pulmonary infiltration and eosinophilia coincided with the administration of cromolyn sodium (Intal), which is known to produce PIE syndrome (pulmonary infiltration and eosinophilia), vasculitis and allergic granulomatosis, while multifocal neuropathy with vasculitis appears not to have been reported in connection with this substance.