Diffuse alveolar hemorrhage and myositis complicating eosinophilic granulomatosis with polyangiitis: a case report and narrative review

BACKGROUND: Eosinophilic granulomatosis with polyangiitis (EGPA) is an uncommon antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis characterized by asthma, eosinophilia, and multisystem involvement. Diffuse alveolar hemorrhage and myositis are both infrequent manifestations of EGPA, and their co-occurrence in the same patient has rarely been reported. CASE PRESENTATION: A 46-year-old man with adult-onset asthma, chronic sinusitis, and marked peripheral eosinophilia was diagnosed with EGPA in 2015. Over six years of follow-up, he had recurrent pulmonary relapses with migratory infiltrates and developed gastrointestinal involvement, nondilated cardiomyopathy, coronary artery disease, myositis, and diffuse alveolar hemorrhage; he was positive for myeloperoxidase (MPO)-ANCA. Disease activity persisted despite high-dose glucocorticoids, azathioprine, cyclophosphamide, and mycophenolate mofetil. Because the disease was severe, organ-threatening, and predominantly vasculitic, an anti-interleukin-5 agent was not chosen for remission induction; instead, rituximab was started and induced sustained remission. CONCLUSION: This case illustrates that refractory, MPO-ANCA-positive EGPA may respond to B-cell depletion with rituximab. The randomized REOVAS trial did not show rituximab to be superior to conventional remission-induction therapy; however, it was not designed to establish equivalence with cyclophosphamide in severe disease, and the optimal strategy for severe refractory disease remains undefined. ANCA status, together with the pattern and severity of organ involvement, may help individualize treatment in this setting.