Yuto Nishiyama, Mimiko Matsumura, Yukiko Yasui, Nozomi Omizo, Takahiro Saito, Miho Kawashima, Nayuta Seto, Yuichiro Nagase, Shinichiro Morioka, Daisuke Katagiri, Hideki Takano
Staphylococcus-associated glomerulonephritis (SAGN) is a subtype of infection-related glomerulonephritis (IRGN) that often affects older adults and can progress rapidly. The role of immunosuppressive therapy in IRGN remains controversial due to the risk of worsening infection and limited evidence from randomized controlled trials. In this report, we present the case of a 70 year-old woman who developed bacteremia, pyogenic sacroiliitis, and multiple iliopsoas abscesses caused by methicillin-susceptible Staphylococcus aureus. While receiving pathogen-directed antibiotics, the patient developed acute kidney injury (peak serum creatinine level, 5.48 mg/dL) with gross hematuria and nephrotic-range proteinuria and subsequently required hemodialysis. Renal biopsy revealed endocapillary hypercellularity and cellular-to-fibrocellular crescents with mesangial expansion and hypercellularity. Immunofluorescence tests demonstrated IgA-dominant deposits with C3, and electron microscopy revealed mesangial-to-subendothelial electron-dense deposits, supporting the diagnosis of IgA-dominant SAGN. Glucocorticoid treatment was initiated after confirming regression of the iliopsoas abscesses and objective evidence of infection control, while continuing pathogen-directed antibiotics. Renal function gradually improved, and hemodialysis was discontinued. In patients with crescentic IgA-dominant SAGN with objectively confirmed infection control and progressive renal dysfunction despite adequate antimicrobial therapy, a carefully timed glucocorticoid treatment strategy, with continued antibiotic therapy and close monitoring, may lead to recovery of renal function and hemodialysis withdrawal.