IgA-Dominant Infection-Related Glomerulonephritis Due to Mycobacterium avium: A Case Report

Immunoglobulin A-dominant infection-related glomerulonephritis (IgA-DIRGN) is a rare variant of acute postinfectious glomerulonephritis, typically seen in elderly individuals with comorbid conditions. IgA-DIRGN is characterized by diffuse endocapillary proliferation and the formation of mesangial deposits of IgA and C3, leading to inflammation and subsequently resulting in acute kidney injury, proteinuria, hematuria, and hypocomplementemia. In this report, we describe an immunocompromised 68-year-old man who developed acute kidney injury, nephrotic-range proteinuria, and microscopic hematuria following a splenic Mycobacterium avium abscess. Kidney biopsy showed endocapillary proliferative glomerulonephritis with IgA and C3-dominant granular deposits, consistent with IgA-DIRGN. Progression of kidney dysfunction during antimycobacterial therapy prompted the use of glucocorticoids 1 month after the initial presentation and eventually a splenectomy 1 month later, followed by renal recovery. To our knowledge, this is the first case to report the association between a nontuberculous mycobacterial infection and IgA-DIRGN, emphasizing the importance of source control and illustrating the usefulness of steroids in this patient.