Granulomatosis with Polyangiitis (GPA) in COVID-19 Era: A Diagnostic Challenge

Granulomatosis with polyangiitis (GPA) is a rare autoimmune disorder part of systematic vasculitis diseases. Respiratory and renal involvement is the hallmark of this disease. The diagnosis of this rare systemic disease becomes more challenging during the COVID-19 pandemic, which affects also lungs and kidneys. Chest computed tomography (CT-scan) findings are considered diagnostic of COVID-19, especially in outbreak areas. We report a case of a 37-year-old male presenting during the COVID-19 pandemic with epigastric pain and fatigue mainly. Incidentally, ground glass opacities were found on the thoracic cuts of the abdominal CT scan. The patient suffered also from an acute kidney injury with nephrotic range proteinuria. Further workup, the patient was found to have positive c-ANCA (PR3+), suggesting of granulomatosis with polyangiitis supported by kidney biopsy findings. Finally, serology and a second SARS-CoV-2 real-time polymerase chain reaction (RT-PCR) were done and turned out to be negative. Hence we were in front of a case of granulomatosis with polyangiitis that was at first mistaken for COVID-19.