ABSTRACT
Introduction: Renal disease in COVID-19 is often due to acute tubular injury but can include multiple glomerular lesions such as collapsing glomerulopathy. This is the first reported case of COVID-19-associated PGNMID. Case Description: A 71-year-old woman with normal baseline creatinine (Cr) was admitted with COVID-19 and discharged on oxygen and dexamethasone (Dex). She improved but returned a month later with edema and nausea. She was found to have nephrotic syndrome, hematuria, and AKI (peak Cr 8.5 mg/dL) requiring HD. Kidney biopsy revealed PGNMID with clonal IgG3-kappa. SPEP, serum free light chains (sFLC), 24h urine UPEP, bone marrow biopsy with flow cytometry, fat pad biopsy, and PET-CT were negative for monoclonal immunoglobulin (Ig) or cell line, amyloid, or malignancy. Though symptoms had long since resolved, she was still PCR-positive for SARS-CoV-2 on nasal swab. Upon discharge she was given cyclophosphamide (Cy). Her renal function improved (Cr 2.5) and she came off HD 2 weeks later. Her outpatient oncologist opted not to continue therapy. However, 2 months later she was readmitted with nausea, dyspnea, and anasarca with recurrent AKI (Cr 6.7) and nephrotic syndrome. HD was restarted. Repeat kidney biopsy [Figure] was noted to be a carbon copy of the first. SPEP, spot UPEP, and sFLC were again negative. She was started on Cy, bortezomib, and Dex with similar partial response (Cr <2.5). Discussion: PGNMID is a rare type of monoclonal gammopathy of renal significance (MGRS) that often has no detectable extrarenal monoclonal Ig or cell line. MGRS and PGNMID, though usually not postinfectious, have been reported with other viruses (e.g., viral hepatitis, parvovirus-B19). However, though causality is unclear, this is the first case of MGRS reported in association with COVID-19.