Reactive arthritis attributable to Shigella infection: a clinical and epidemiological nationwide study.

OBJECTIVES To study the incidence and clinical picture of Shigella associated reactive arthritis (ReA) and the arthritogenicity of various Shigella species in the population. METHODS A questionnaire on enteric and extraintestinal, especially musculoskeletal, symptoms was sent to 278 consecutive patients with Shigella positive stool culture and to 597 controls. Analysis of self reported musculoskeletal symptoms was supplemented with clinical examination of those subjects with recent symptoms. RESULTS Of the patients, 14/211 (7%) had ReA, and a further 4/211 (2%) other reactive musculoskeletal symptoms (tendonitis, enthesopathy, or bursitis). Of the 14 patients with ReA, all adults, 10 had S sonnei, three S flexneri, and one S dysenteriae infection. HLA-B27 was positive in 36% of the patients with ReA. One control subject had ReA. In the patients with Shigella infection, the odds ratio for developing ReA was 16.2 (95% confidence interval 2.1 to 123.9), p = 0.001. CONCLUSIONS ReA occurred in 7% of patients after Shigella infection, with an annual incidence of 1.3/1 000 000 in Finland. Besides S flexneri, S sonnei and S dysenteriae can also trigger ReA.