Microscopic polyangiitis associated with coronavirus disease-2019 (COVID-19) infection in an elderly male.

Background: Microscopic polyangiitis (MPA) is an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) that affects predominantly small- sized vessels. A causal relationship between viral infections and vasculitis has been postulated.Aim of the workTo present the concomitant association of coronavirus disease 2019 (COVID-19) infection with MPA in an elderly Iranian male. Case presentation: A 67 year old Iranian man with the history of COVID-19 infection and a positive polymerized chain reaction (PCR) test four weeks before admission to the neurology department with acute onset pain, numbness and progressive weakness in both hands grip, sudden left foot drop and paresthesia. Erythrocyte sedimentation rate (ESR) was 95 mm/hr, ferritin 912 ng/ml and C-reactive protein (CRP) positive, proteinuria 1.1 g/24 h and markedly elevated perinuclear (P-ANCA): 526 IU/ml. Diagnosis of MPA was held presenting with mononeuritis multiplex, glomerulonephritis followed by diffuse alveolar hemorrhage and infiltration of lymphocytes in muscle fibers and vessels wall in sural nerve biopsy. He was successfully treated by methylprednisolone (1 g/day for 3 days) followed by 1 mg/kg with gradual tapering along with cyclophosphamide (CYC) (2 mg/kg). Intravenous immunoglobulin (IVIG, 2 g/kg in four divided doses) started for the management of inflammatory mononeuritis multiplex with gradual improvement. During hospitalization, plasmapheresis was performed due to alveolar hemorrhage for 5 day. The patient returned home on day 32 and followed-up in the rheumatology clinic with improvement of muscle power and handgrip strength. Conclusion: Vasculitis is potentially one of COVID-19's presenting symptoms and prompt diagnosis and treatment is crucial in improving outcome of patients.