Clostridioides difficile osteomyelitis diagnosed in a man with chronic kidney disease after initial antibiotic failure
Background
Clostridioides difficile infection (CDI) is primarily known for causing severe gastrointestinal disorders, including colitis and diarrhea. However, a growing body of evidence indicates that C. difficile can cause extraintestinal pathologies, which are often challenging to diagnose due to their rarity and atypical presentation. Bone infections, or osteomyelitis, caused by C. difficile are exceedingly rare and can easily be mistaken for other conditions, including malignancy or more common bacterial osteomyelitis. This diagnostic ambiguity often leads to delayed appropriate treatment, highlighting a critical gap in understanding the full spectrum of C. difficile pathogenicity.
Study Design
Clinicians evaluated a man in his 70s with chronic kidney disease who presented with a longstanding, painless, fluctuant anterior lower leg mass. Initial imaging revealed a proximal tibial lytic lesion, and aspiration of a superficial collection yielded C. difficile. Despite 4 weeks of oral amoxicillin-clavulanate (875-125 mg every 12 hours) plus oral metronidazole (500 mg every 8 hours), his symptoms persisted. Subsequent MRI demonstrated chronic tibial osteomyelitis. He then underwent excisional debridement with dead-space management and local vancomycin, followed by prolonged pathogen-directed antimicrobials.
Results
Initial broad-spectrum antibiotic therapy with amoxicillin-clavulanate and metronidazole for 4 weeks failed to resolve the patient's symptoms. MRI imaging was crucial, revealing chronic tibial osteomyelitis with cortical disruption and a contiguous intramedullary and soft tissue abscess, consistent with a Brodie's abscess. > Deep intraoperative cultures, taken after initial aspiration, again yielded rare Clostridioides difficile, while aerobic and blood cultures were negative, confirming the unusual etiology. The patient improved significantly following surgical debridement and targeted antimicrobial therapy, avoiding amputation. He remained stable at 9-month follow-up, demonstrating successful resolution of this rare infection.
Why It Matters
This case underscores the critical importance of considering rare etiologies like Clostridioides difficile osteomyelitis when patients present with atypical bone lesions, especially in those with predisposing factors like chronic kidney disease. Clinicians should be aware that C. difficile can cause extraintestinal infections that mimic more common conditions, leading to diagnostic delays. Persistent symptoms despite conventional broad-spectrum antibiotics should prompt further investigation, including specific anaerobic cultures, to identify unusual pathogens. This case highlights that targeted surgical debridement combined with pathogen-directed antimicrobial therapy, such as local vancomycin, can lead to successful outcomes even in complex, rare infections, preventing severe complications like amputation.