A combination of disk space narrowing and vacuum phenomenon on radiographs of the spine is usually considered a reliable indicator of degenerative disk disease. We report a case in which vacuum phenomenon was related to Clostridium perfringens discitis.

A 79-year-old woman was admitted for inflammatory low back pain that had worsened steadily over the last 2 months. Her body temperature was normal, laboratory tests showed inflammation (erythrocyte sedimentation rate, 61mm/h; and C-reactive protein, 13mg/L), and blood cultures were negative. Imaging studies (radiographs, computed tomography [CT], and magnetic resonance imaging) indicated L4–L5 discitis. Vacuum phenomenon within the L4–L5 disk was seen on radiographs and CT scans. C. perfringens was recovered by fine-needle biopsy of the disk. Diverticular disease of the colon was the only identifiable portal of entry. Amoxicillin therapy ensured a full recovery.

C. perfringens discitis is rare, with only 7 published cases in humans. A gastrointestinal portal of entry was identified in 70% of cases. Radiographs or CT scans visualized vacuum phenomenon in 80% of cases. Positive blood cultures were noted in 75% of cases. The outcome was favorable with antibiotic therapy, even when a single-drug was used. The other characteristics of C. perfringens discitis were indistinguishable from those of discitis caused by the usual organisms.

Presence of gas within the disk does not rule out infectious discitis and may indicate C. perfringens discitis.