Granulomatosis With Polyangiitis and Concomitant Superinfection: A Defying Diagnosis and Management Approach

Granulomatosis with polyangiitis (GPA) is a systemic necrotizing vasculitis mainly involving the ear, nose, and upper and lower airways. Diagnosis is based on clinical manifestations, positive antineutrophil cytoplasmic antibodies (ANCA) serology, and histopathological findings. We report a case of inflammatory polyarthralgia with a high titer of rheumatoid factor (RF), which was revealed to be GPA after extensive diagnosis workup. However, the disease was complicated by superinfections, which delayed and limited immunosuppressive treatment. Methotrexate was at last initiated with antibiotic prophylaxis, and there was significant clinical improvement. This case underlines the importance of an adequate diagnosis workup and the difficulties that often arise when other entities are present.