Interspinous Bursitis due to Staphylococcus aureus in an Adolescent.

BACKGROUND: Interspinous bursitis is exceptionally rare in children, contrasting with degenerative forms in adults. CASE PRESENTATION: A 16-year-old male presented with acute severe low back pain, fever (39°C), and focal L3-L5 tenderness. CRP was 233 mg/L; blood cultures grew methicillin-susceptible Staphylococcus aureus. Imaging progression (US, CT-scan, MRI, PET-CT) confirmed L3-L4 interspinous bursitis without bone/disc involvement, distinguishing it from spondylodiscitis. MANAGEMENT: Cefazolin IV (10 days) followed by oral ciprofloxacin (4 weeks), a lumbar brace, and rehabilitation yielded complete recovery. CONCLUSIONS: Pediatric interspinous bursitis presents as febrile back pain via hematogenous dissemination. MRI is diagnostic, excluding spondylodiscitis. Conservative management with early antibiotic switch is effective when imaging excludes bone/disc involvement. This case highlights distinguishing features and optimal management of this rare pediatric entity.