Septic arthritis of a lumbar facet joint caused by Staphylococcus aureus.

STUDY DESIGN

Case report of a 35-year-old woman with septic arthritis of a lumbar facet joint.

OBJECTIVES

To report a rare case of severe low back pain and the specific differential diagnostic problems.

SUMMARY OF BACKGROUND DATA

Differential diagnosis between spondylodiscitis and facet joint septic arthritis on a clinical basis is very difficult. The lesions of the joint appear on a plain film only approximately 1.5 months after onset of the symptoms. Although the radionuclide bone scan is sensitive and shows a more laterally and vertically localized uptake than in spondylodiscitis, this technique is not very specific. Computed tomography scan and magnetic resonance imaging are the most reliable investigations even at the very early stages of the disease. Confirmation of the diagnosis has to be obtained by blood cultures or, in exceptional cases, by direct puncture of the joint. Appropriate antibiotic treatment is in most cases sufficient to heal this lesion.

METHODS

The etiology, clinical presentation, technical examinations, and treatment are reviewed.

RESULTS

Computed tomography scan and magnetic resonance imaging complemented by positive blood cultures led to the very early diagnosis of septic arthritis of the lumbar facet joint in this relatively young patient.

CONCLUSIONS

With our case report we confirm the very small number of data reported in the literature, indicating that infections of the facet joint can be detected at a very early stage using magnetic resonance imaging and computed tomography scan.