Unusual Postpartum Sacroiliitis Due to Burkholderia contaminans: Diagnostic Considerations From a Single Case

Infectious sacroiliitis is a rare and often misdiagnosed condition, particularly in postpartum women, where symptoms may mimic benign musculoskeletal pain. We describe a postpartum woman who developed severe lumbar and gluteal pain four days after a cesarean section. Examination revealed sacroiliac joint tenderness, positive FABER and Gaenslen tests, and mild asymmetrical lower extremity weakness. MRI demonstrated left-sided sacroiliitis with periarticular edema. Blood and synovial fluid cultures confirmed Burkholderia contaminans, an unusual finding in this clinical setting, which guided targeted therapy with trimethoprim-sulfamethoxazole. The patient completed intravenous followed by oral treatment, resulting in rapid pain relief, normalization of inflammatory markers, and complete recovery. This case highlights the diagnostic challenge of sacroiliitis in postpartum women, where inflammatory marker elevation may be modest. It underscores the importance of a focused sacroiliac joint examination, culture confirmation, and susceptibility-guided therapy, while reminding clinicians to consider unusual pathogens when standard organisms are not isolated.