IgA Dominant Infection Related Glomerulonephritis Mimicking Primary IgA Nephropathy in Methicillin-Sensitive...

IgA-dominant infection-related glomerulonephritis (IgA-IRGN) is a histopathological variant of staphylococcus-associated glomerulonephritis (SAGN) that occurs as a result of an immune response to S. aureus antigens, with subsequent deposition of IgA in the nephron. This can lead to acute kidney injury, hematuria, and proteinuria. It is important to differentiate IgAIRGN from primary IgA nephropathy (IgAN) because the treatment strategies differ. IgA-dominant IRGN requires treatment of the infection with antibiotics, whereas treatment of primary IgAN involves immunosuppression. Here, we present a case that highlights the clinical dilemma of distinguishing IgA nephropathy from IRGN. Our patient presented with chronic osteomyelitis secondary to Staph. The hospital course was complicated by acute renal failure that required dialysis. Renal biopsy showed IgA deposits, and the patient was initially treated with steroids for IgA Nephropathy. The patient did not respond to immunosuppressive treatments and had a second biopsy, clinical history, and course that closely resembled IgA-IRGN. The patient was eventually removed from dialysis after five months. In patients with documented S. aureus infection who present with acute kidney injury, hematuria, and proteinuria, IgA-IRGN should be considered as the etiology. Source control measures should be attempted when necessary and patients should be treated with an appropriate course of antibiotics. Proper diagnosis is important to avoid exposure to immunosuppressive medications and potentially worse outcomes in these patients.