Diagnostic Challenges of Infection-Related Glomerulonephritis: A Case of Progressive AKI in the Setting of Osteomyelitis Clarified through Renal Biopsy

Acute kidney injury (AKI) and glomerulonephritis have diverse causes and pathophysiology. Infection-related glomerulonephritis varies in presentation and pathology depending on the pathogen and severity. Classically, exudative glomerulonephritis results from the infiltration of neutrophils; however, this is complicated by multifactorial glomerular injury, including medical comorbidities and nephrotoxic agents [1]. A 73-year-old female presented with worsening renal function following treatment for a soft tissue infection of the left third toe. The patient developed uremic symptoms during a course of sulfamethoxazole-trimethoprim, which was subsequently discontinued given concerns for drug-induced AKI. Despite discontinuation of the medicine and conservative treatment for suspected osteomyelitis, renal dysfunction progressed. Renal biopsy revealed exudative glomerulonephritis consistent with an infectious process and acute tubular necrosis (ATN). Subsequently, definitive source control was achieved through surgical intervention for the osteomyelitis. This case emphasizes the importance of source control for cases refractory to parenteral antibiotics and emphasizes the importance of renal biopsy histopathology for management.