A Case of Myositis Preceding Neuropathy in Eosinophilic Granulomatosis with Polyangiitis

Abstract

Dear Editor, Eosinophilic granulomatosis with polyangiitis (EGPA; also called Churg-Strauss syndrome) is a necrotizing vasculitis affecting small-to-medium-size vessels of multiple organs. Most patients exhibit respiratory involvement, such as pulmonary infiltrates, allergic rhinitis, or asthma. The nervous system is also commonly affected, most frequently as a mononeuritis multiplex. 1 Myalgia may appear during the course of EPGA, 2 but it is rarely a major complaint. Muscle weakness is typically attributed to peripheral neuropathy rather than to primary myositis, resulting in muscle biopsies rarely being performed. However, we recently experienced a case of EGPA that showed inflammatory myopathy that preceded the onset of peripheral neuropathy. A 78-year-old male presented with myalgia and muscle weakness in the thighs and calves that had first appeared 3 weeks previously, and had been accompanied by fever for the previous 1 week. He was unable to walk without support. The power in hip flexion was Medical Research Council (MRC) grade 3 (of 5), while it was MRC grade 4 for ankle dorsiflexion on both sides. Myalgia was most prominent in the posterior thighs and calves. He complained of paresthesia over his legs, but did not show any primary sensory deficit. He had been treated for asthma for 5 years with leukotriene-receptor antagonist, xanthine, inhaled corticosteroid, beta-2 agonist, and muscarinic antagonist. He had suffered an exacerbation of asthma with eosinophilia 2 years previously, which was alleviated by a short course of systemic corticosteroid.