Recurrent atelectasis and brain infarction in a patient with anti-neutrophil antibody negative eosinophilic granulomatosis with polyangiitis: a case report

BACKGROUND: Eosinophilic granulomatosis with polyangiitis (EGPA) is an anti-neutrophil antibody (ANCA)-associated necrotizing vasculitis, which predominantly affects small to medium vessels, and is associated with asthma and eosinophilia. EGPA has two different pathogenic aspects: eosinophilic granulomatous inflammation and ANCA-associated inflammation. A recent histological study of peripheral nerves showed that not only ANCA-associated inflammation but also eosinophil-associated vascular occlusion leads to ischemia. Endobronchial involvement is relatively common especially in the patients with granulomatosis with polyangiitis but rare in patients with EGPA. Central nervous system (CNS) involvement is also rare in patients with EGPA, the pathogenesis and relationship between these two rare conditions have not been elucidated. CASE PRESENTATION: A 62-year-old woman was admitted with numbness, purpura, and eosinophilia. She had a 3-year-history of bronchial asthma. Chest computed tomography showed left lower lobe collapse, and brain magnetic resonance imaging indicated occipital lobe infarction. Skin biopsy findings led to the diagnosis of EGPA. ANCA test results were negative. All symptoms improved after initiating glucocorticoids. However, atelectasis and brain infarction relapsed with increasing eosinophil counts. Atelectasis quickly disappeared with increasing glucocorticoid dose, and glucocorticoid could be reduced to a maintenance dose after the initiation of mepolizumab. CONCLUSION: Both atelectasis and brain infarction might develop not only via ANCA-associated inflammation but also via eosinophilic inflammation.