Case Report: Successful treatment of

Background: Infectious crescentic glomerulonephritis (CrGN) is a rare but severe complication in kidney transplant (KTx) recipients. Case presentation: A 64-year-old man with a history of two kidney transplants presented with a 3-week deterioration in renal function, progressing to nephritic syndrome (urine protein creatinine ratio (UPCR) 5.1 g/g, albumin 22 g/L, hypertension, and peripheral edema [+6 kg over 1 week]) and oliguric acute kidney injury (peak creatinine 684 μmol/L). Renal biopsy showed CrGN with IgM/IgA/C3 deposits, suggesting immune complex-mediated pathology. Initial investigations, including blood cultures, two transthoracic echocardiograms performed 1 week apart, and PET scan, ruled out infective endocarditis. Reinterrogation post-biopsy uncovered a cat bite 2 months prior, raising concerns for Management and outcome: The patient received azithromycin (500 mg/day for 5 days) for infection and corticosteroids (5 mg/kg pulse followed by a tapering regimen) for glomerulonephritis. After 2 dialysis sessions, renal function improved as evidenced by recovery urine output, which led to discontinuous of dialysis. A major complication (upper gastrointestinal bleeding) required endoscopic intervention and blood transfusions. Nephroprotective therapy was optimized (irbesartan up titrated from 75 to 150 mg/days and dapagliflozin 10 mg/day introduced), leading to normalization of proteinuria (UPCR 0.5 g/g) at 1-year follow-up. Conclusion: This case underscores the importance of reinterrogating patients for exposure risks (e.g., animal bites) when facing unexplained CrGN, particularly in renal transplant recipients. It also highlights the effectiveness of combined antibiotic and corticosteroids therapies in managing infectious glomerulonephritis. Clinicians should consider