[Clinical and imaging characteristics of patients with different types of infectious sacroiliitis]

To investigate the clinical manifestations and imaging characteristics of patients with different types of infectious sacroiliitis. Clinical data of 40 patients diagnosed with infectious sacroiliitis were retrospectively analyzed. Among the 40 patients, 16 patients were diagnosed as non-brucellar and non-tuberculous infectious sacroiliitis (ISI), 13 with tuberculous infectious sacroiliitis (TSI), and 11 with brucellar sacroiliitis (BSI). In the ISI and TSI group, female patients accounted for 11/16, 12/13, while the proportion of unilateral involvement was 15/16 and 12/13, respectively. Compared with ISI and TSI group, BSI patients were mainly male (8/11) and presented more bilateral involvement (6/11) (P<0.05). Bone erosion was more common in ISI and TSI groups than in BSI group (6/15, 7/11 and 2/10), as well as abscess formation (3/15, 4/11 and 1/10, respectively). Symptoms in all patients relieved 1-2 weeks after administration of antibiotics or anti-tuberculosis treatment, but the resolution of the magnetic resonance imaging findings delayed about 6 (3-9) months. ISI and TSI patients with infectious sacroiliitis should be differentiated from spondyloarthritis, with a characteristic of more female patients, unilateral sacroiliitis, bone erosion, soft tissue involvement and abscess formation. However, BSI patients are mainly male, more bilateral involvement and less bone destruction and abscess formation. Antibiotic therapy demonstrates significant therapeutic effects, but resolution of the magnetic resonance imaging findings responses late.