Joint Bone Spine 77 (2010) 76–77 Case report Hematogenous Staphylococcus aureus discitis in adults can start outside the vertebral body Florence Millot a , Bruno Bonnaire b , Gaëlle Clavel a , Hervé Deramond b , Patrice Fardellone a , Franck Grados a,∗ a Service de rhumatologie, hôpital Nord, CHU d’Amiens, 80054 Amiens cedex 1, France b Service de radiologie, hôpital Nord, CHU d’Amiens, 80054 Amiens cedex 1, France article info Article history: Accepted 11 May 2009 Keywords: Discitis Spondylodiscitis Epidural abscess Magnetic resonance imaging abstract Background: Textbooks describe hematogenous discitis in adults as starting in the anterior vertebral body near the endplates. Case report: Hematogenous Staphylococcus aureus discitis developed at L1–L2 in an 81-year-old woman. On the first magnetic resonance imaging (MRI) scan performed 4 days after symptom onset, the only abnormalities were high signal from the disk on T2-weighted images, gadolinium enhancement of the soft tissues anterior to L1–L2, and epidural involvement. The endplates and vertebral bodies were normal. A subsequent MRI scan showed features typical of infectious discitis. Discussion: We found a single similar case report in the medical literature, indicating that discitis starting outside the anterior vertebral body is rare. Nevertheless, an increasing number of similar cases may be diagnosed in the future, as MRI is being performed increasingly early in patients with a clinical suspicion of infectious discitis. Conclusion: Hematogenous infectious discitis in adults may start in some patients within the disk, soft tissues anterior to the disk, or epidural space. To avoid diagnostic and therapeutic delays, physicians should be aware of this unusual presentation of infectious discitis on very early MRI scans. When the clinical picture suggests discitis and findings from the early MRI scan are atypical, a repeat MRI scan should be obtained 1 week later to confirm the diagnosis. © 2009 Société franc ¸ aise de rhumatologie. Published by Elsevier Masson SAS. All rights reserved. 1. Introduction Hematogenous pyogenic discitis in adults is classically described as the result of a septic arterial embolus to the anterior vertebral body near the endplates where the terminal feeding arter- ies end [1–3]. Each branch of the posterior feeding artery supplies the inferior portion of one vertebral body and the superior portion of the next lower vertebral body. In contrast to children and adoles- cents, adults normally have no vascular supply to the intervertebral disks. We report a case of discitis in which the early magnetic res- onance imaging (MRI) findings suggest a starting point outside the vertebral body. 2. Case report An 81-year-old woman started experiencing severe low back pain with an inflammatory time pattern 2 days after undergoing coronary angiography. She had a fever of 39 ◦ C. Her medical history ∗ Corresponding author. E-mail address: grados.franck@chu-amiens.fr (F. Grados). was remarkable for coronary artery disease and osteoporotic fractures. The clinical neurological examination was normal. Blood tests showed systemic inflammation (C-reactive protein [CRP], 192 mg/L) and leukocytosis of 11,900/mm 3 with 90% neutrophils. Two blood cultures were positive for methicillin-sensitive Staphy- lococcus aureus. MRI performed 4 days after pain onset (Fig. 1) showed a previous fracture of L1, dappled high signal from the L1–L2 disk on T2-weighted and STIR sequences, gadolinium enhancement of the soft tissues anterior to the L1–L2 disk, and epidural involvement anterior and posterior to L1 and L2. The vertebral bodies and endplates were normal. She was treated with oxacillin 8 g/d intravenously for 2 weeks combined with netilmicin 240 mg/d intravenously for 7 days fol- lowed by oral ofloxacin 600 mg/d then with oral ofloxacin and rifampin 1200 mg/d for a total of 3 weeks. The CRP level declined to 50 mg/L. However, she continued to experience severe inflam- matory low back pain, and her CRP level increased to 75 mg/L at discontinuation of the antimicrobials, prompting her transfer to our rheumatology department. A second MRI scan performed 5 weeks after pain onset (Fig. 2) showed findings typical of L1–L2 discitis with epidural involvement (T1-weighted sequence: low signal from the L1 and L2 vertebral bodies; disappearance of the 1297-319X/$ – see front matter © 2009 Société franc ¸ aise de rhumatologie. Published by Elsevier Masson SAS. All rights reserved. doi:10.1016/j.jbspin.2009.10.010