Neisseria meningitidis-induced discitis at L5-S1 mimicking lumbar disc herniation

Abstract

A 23-year-old man presented to his general practitioner with a 2-week history of increasing lumbar back pain and left-sided radiation at S1, with progressive motoric loss of function of S1 on the right side but with intact sensibility. On lumbar MRI, a medial L5-S1 disc herniation was identified (figure) and oral corticosteroid therapy (prednisolone 100 mg daily for 5 days) was initiated. Because the back pain and radiculopathy did not regress and a progressive functional motoric loss of function of S1 (M3) was present, he underwent microdiscectomy 2 weeks after initial presentation. At admission, the laboratory results showed moderately increased serum C-reactive protein (50 mg/L) and leukocyte count (12 × 109 cells per L). Preoperative antimicrobial prophylaxis with intravenous cefuroxime (1·5 g as a one-off injection) was administered. Intraoperatively, pus was detected in the epidural space and disc niche, hence lavage of the disc space and collection of two disc tissue biopsies followed. Antibiotic treatment with intravenous co-amoxiclav (2·2 g every 6 h for 7 days) was initiated postoperatively. Histopathological examination showed focal lymphoplasmacytic, partly granulocytic inflammation, which was consistent with discitis. Cultures of intraoperatively sampled tissue biopsies remained without bacterial growth, but broad-spectrum PCR identified Neisseria meningitidis (subgroup W135) in both disc tissue specimens. Antimicrobial treatment was subsequently changed to targeted therapy with intravenous ceftriaxone (2 g once daily for 14 days). On postoperative day 8, the patient had an exacerbation of pain. Despite debridement of the abscess at the first intervention, persistent epidural abscess collection was visible in the ensuing obtained lumbar MRI, which resulted in a second-look surgery with extensive lavage and abscess evacuation on the same day. Intraoperative tissue biopsies remained culture-negative; however, N meningitidis was identified by PCR again in three of six specimens (four disc tissue specimens and two abscess fluid specimens) taken during the second surgery. Subsequently, pain subsided substantially with extended oral analgesic treatment consisting of oral diclofenac (75 mg twice daily), oral metamizol (500 mg four times daily), oral tapentadol (150 mg prolonged-release tablet every 12 h), and oral pregabalin (50 mg three times daily), which was adminstered for 28 days. The patient was discharged on postoperative day 12 after index surgery still having increased inflammatory markers (C-reactive protein 47 mg/L, leukocyte count 9·7 × 109 cells per L). After 9 days of intravenous ceftriaxone (2 g once daily), oral ciprofloxacin (750 mg twice daily) was administered to complete the 6-week course of antimicrobial therapy for bacterial spondylodiscitis. The patient regained complete motor function at 6 weeks after the first surgery. Inflammatory laboratory parameters were completely resolved at 3 months of follow-up, and back and leg pain resolved at 6 months of follow-up.