RESUMEN
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection triggers elevated levels of circulating cytokines and immune-cell hyperactivation, called a cytokine storm, which leads to dysregulated immune response not only towards the pathogen itself but also contributes to cellular, vascular injury and multiorgan dysfunction. The cytokine-induced endothelial inflammation and vascular pathology of COVID-19 is well reported in post-mortem biopsies and several cases reporting small, medium and large vessel micro/macro thrombotic events and vasculitis in multiple organs. So far, few cases have been reported with newly diagnosed antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis at the time of acute COVID-19 infection. The exact pathophysiology of SARS-CoV-2 and ANCA-associated vasculitis continues to be studied and reviewed. Here we report a case of a 60-year-old female who presented to our institution with sudden onset of shortness of breath and hemoptysis. A detailed history revealed a recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Labs showed elevated serum creatinine, urine analysis with large blood and nephrotic range proteinuria. CT chest was remarkable for abnormal appearance of the parenchyma bilaterally compatible with a crazy paving pattern, suggesting pulmonary alveolar proteinosis versus diffuse alveolar hemorrhage. Vasculitis was suspected and the patient was started on IV corticosteroids and plasmapheresis. Diagnostic workup was positive for antineutrophil cytoplasmic antibodies-myeloperoxidase (ANCA-MPO), anti-Sjögren's syndrome-related antigen A autoantibodies (anti-SS-A) and antinuclear antibodies (ANA). Renal biopsy confirmed focal segmental necrotizing, crescentic and sclerosing glomerulonephritis, pauci-immune type, anti-MPO antibody/P-ANCA associated. A diagnosis of microscopic polyangiitis was made and she was started on rituximab immunosuppressive therapy following which she showed clinical improvement. In this document, we present a unique case of microscopic polyangiitis possibly induced by SARS-CoV-2 infection confirmed by renal biopsy and clinical presentation. In the current setting of a global pandemic, we strongly recommend that vasculitis be high on the differential diagnosis in patients who are currently infected or had been infected with SARS-CoV-2 and present with acute kidney injury (AKI).
RESUMEN
RATIONALE: Pulmonary renal syndrome (PRS) is a term most commonly used to describe a combination of glomerulonephritis and pulmonary hemorrhage as a manifestation of a multisystem autoimmune disease. It is usually associated with ANCA vasculitis and anti-GBM disease. Diffuse alveolar hemorrhage in a patient with ANCA and anti-GBM negative pauci-immune glomerulonephritis is rare and optimal management is unknown. PATIENT CONCERNS: An 85-year-old man with hypertension, diabetes mellitus, prostate cancer and recently diagnosed pauci-immune necrotizing glomerulonephritis presented to our emergency department with worsening dyspnea and pedal edema for several days. Clinical presentation and radiological studies were suggestive of fluid overload but he developed worsening respiratory failure despite hemodialysis. DIAGNOSES: Bronchoscopy confirmed diffuse alveolar hemorrhage. ANCA and anti-GBM antibodies were negative. The patient was diagnosed with pulmonary renal syndrome - diffuse alveolar hemorrhage in the setting of ANCA and anti-GBM negative pauci-immune glomerulonephritis. INTERVENTIONS: Patient was started on intravenous pulse steroids, cyclophosphamide and received seven sessions of plasmapheresis. OUTCOMES: There was an improvement in patient's respiratory status and repeat bronchoscopy at the end of treatment did not show diffuse alveolar hemorrhage. LESSONS: Pauci-immune crescentic necrotizing glomerulonephritis is usually associated with the presence of ANCA, however, ANCA may be absent in 10% of these cases. Immunosuppression is the mainstay of treatment for ANCA and anti-GBM associated PRS. This case highlights the importance of immunosuppression and plasmapheresis in patients with ANCA negative vasculitis due to presence of unidentified serum antibodies. If left untreated, these patients can have a fulminant course with high mortality ranging from 25 to 50%.