Human brucellosis mimicking axial spondyloarthritis: a challenge for rheumatologists when applying the 2009 ASAS criteria

Abstract

Although the development of the 2009 SpA classification criteria by Assessment of SpondyloArthritis international Society (ASAS) represents an important step towards a better definition of the early disease stage particularly in axial spondyloarthritis (axSpA), the specificity of the criteria has been criticized these days. As the commonest zoonotic infection worldwide, human brucellosis can mimic a large number of diseases, including SpA. This study was performed to determine the frequency of rheumatologic manifestations in patients with brucellosis and the chance of misdiagnosing them as having axSpA in central China. The results showed that clinical manifestations of axSpA could be observed in brucellosis. Over half of patients had back pain, and one fifth of the patients with back pain were less than 45 years old at onset and had the symptom for more than 3 months. Two young males were falsely classified as suffering from axSpA according to the ASAS criteria, and one with MRI proved sacroiliitis was once given Etanercept for treatment. Therefore, differential diagnosis including human brucellosis should always be kept in mind when applying the ASAS criteria, even in traditionally non-endemic areas.

Axial Spondyloarthritis: Mimics and Pitfalls of Imaging Assessment

“…Brucellosis is the most common zoonotic infection worldwide (108). Gram negative bacteria have affinity for the SIJ and up to 35-37% of patients with brucellosis have SIJ involvement, usually unilateral.…”

“…Brucellosis can mimic axSpA and even fulfill ASAS classification criteria for axial or peripheral SpA (99,108,109), when assessing for clinical, laboratory and imaging findings. The most important MRI changes are BME and bone erosions in SIJ.…”