Objectives: Arthritis observed in patients with Brucella infection is usually considered to result from live micro-organisms invading the synovia. We observed four cases of brucellosis in which the clinical and laboratory findings suggested a different mechanism: reactive arthritis.
Clinical observations: The diagnosis of brucellosis was made on the basis of serology tests in 3 patients and blood cultures in 1. All 4 patients presented oligoarthritis. The synovial fluid was sterile in 3. Antibiotics were ineffective in reducing joint pain and inflammation whereas local and systemic anti-inflammatory drugs were effective. Three patients also had other manifestations (sausage-shaped toes, talalgia, sacroiliitis) and fulfilled the diagnostic criteria for spondylarthropathy. All patients were positive for antigen HLA-B27.
Discussion: These observations suggest that Brucella should be added to the list of intracellular infectious agents capable of inducing reactive arthritis, despite the lack of all the diagnostic criteria. For some, such as the uretritis or diarrhea observed before joint involvement, it would be difficult to implicate the germ. Brucella serology should be part of the etiology work-up for reactive arthritis in endemic areas.