Dorsal costo-vertebral joint as a rare localization of Staphylococcus aureus sepsis

Background: Septic arthritis of the costovertebral thoracic joint is a rare site infection. We report an isolated case of septic arthritis of the 10th costo-vertebral right joint with osteitis due to Staphylococcus aureus. Case presentation: A 59 year old Tunisian man presented with a 2 months history of dorsal spinal pain with fever, associated with asthenia, anorexia and loss of weight. There was a raised C-reactive protein (176 mg/L) and erythrocyte sedimentation rate (100 mm/1st h). Tests for tuberculosis and brucellosis were negative. In the present patient, the clinical symptoms were unspecific with lack of obvious predisposing factors. He had neither history of taking immunosuppressors nor of any disease indicative of immunodeficiency. Thoraco-abdominal computed tomography (CT) showed a lytic lesion centered on the 10th costo-vertebral right joint and histo-pathologic exam of the costo-vertebral puncture confirmed chronic active osteitis and bacteriologic culture allowed identifying methicillin-sensitive Staphylococcus aureus. The patient was treated with ciprofloxacin 1500 mg/day, associated with daily rifampin (20 mg/kg) for total treatment duration of 12 weeks after consulting infectious disease specialists. After a follow-up of 6 months, the patient remained asymptomatic and the markers of inflammation negative. Conclusion: Septic arthritis of costovertebral joints should be considered when a patient presents with back pain, fever and elevated inflammatory markers. The diagnosis of septic arthritis of costovertebral joints remain a challenge to clinicians. CT is important to confirm a diagnosis and guide costovertebral biopsy and culture. Early and appropriate antibiotic therapy is important for a required outcome. Keywords: Costo-vertebral joint, Staphylococcus aureus, Septic arthritis, Dorsal spine, Computerized tomograph