Pauci-immune glomerulonephritis: Post-COVID kidney disease continues to reappear, a case report.

We present a female in her mid-70s with COVID-19 infection who developed worsening renal function along with systemic symptoms over months. The patient was initially monitored for long COVID and was referred to the nephrologist after she was found to have further worsening of her renal function. She underwent a renal biopsy and findings on light microscopy, immunofluorescence, and electron microscopy were consistent with crescentic glomerulonephritis, pauci-immune type with chronicity, and acute interstitial nephritis. These findings and a positive anti-neutrophilic cytoplasmic antibody immunofluorescence assay (ANCA IFA) and myeloperoxidase antibody confirmed myeloperoxidase-ANCA-positive pauci-immune glomerulonephritis. The patient was started on treatment with corticosteroids and Rituximab, resulting in improvement in her symptoms and renal function.