Anca-associated vasculitis under a COVID-19 mask

ABSTRACT

Introduction: Ground glass opacities (GGO) on CT scan are the hallmark of COVID-19. GGO can also be seen in ANCA-associated lung injury. Additionally, both can present with kidney injury. We report a case of presumed COVID-19 with AKI which was actually severe ANCA-associated vasculitis. Case Description A 74-year old female with a history of hypertension and diabetes, who presented with a week of chills, cough, dyspnea, and watery diarrhea, and a creatinine of 10.2 mg/dl (baseline creatinine 1.02 mg/dl). A month prior to admission, she was treated for presumed bacterial conjunctivitis, followed by otitis media, and then bacterial sinusitis with oral ciprofloxacin. Despite a negative swab, she was admitted with suspicion of COVID-19 given GGO seen on CT scan and an exposure history at her senior home. She was treated per the COVID-19 protocol IV methylprednisolone 125mg, azithromycin, and ceftriaxone. She had microscopic hematuria and 4 grams of proteinuria. ATN was suspected as urine microscopy showed granular casts and no dysmorphic RBC or cellular/WBC/RBC casts. After a repeat negative swab and improvement in respiratory symptoms yet worsening renal function requiring hemodialysis, a full serologic workup was performed. Positive results include p-ANCA (1320), MPO (49), and ANA (1160 homogeneous) without hypocomplementemia. Other autoimmune markers including anti-GBM antibody were negative. A kidney biopsy was performed and showed pauciimmune crescentic glomerulonephritis (GN) with cellular crescents in more than 80% of the glomeruli with minimal interstitial fibrosis and tubular atrophy. Given the frailty of this patient, she was treated with oral prednisone and rituximab instead of cyclophosphamide. She remained on intermittent hemodialysis and tolerated the treatment well. Discussion: This case emphasizes the importance of detecting pulmonary-renal syndrome in the time of COVID-19. Given the current global pandemic and a high volume of infected patients coupled with the lack of sensitivity of the SARS-CoV-2 assays, it is possible to miss this relatively rare ANCA-associated vasculitis. Patient with rapid proliferative GN feature and lung symptoms should be further worked up to avoid missing an ANCA-associated vasculitis. COVID-19 may actually provoke ANCAassociated vasculitis and further testing is underway.