[A clinical analysis of 509 cases of sacroiliitis]

To study the clinical features of sacroiliitis and differential diagnosis.

Totally 509 patients with chief complaints of back pain and diagnosed as sacroiliitis from January 2007 to January in Chinese PLA General Hospital were enrolled. The clinical manifestations, laboratory examinations, imaging and pathological data of the 509 patients were retrospectively analyzed.

There were totally 406 male patients and 103 female patients. Among all 509 patients, 436 were diagnosed as ankylosing spondylitis (AS)/ spondyloarthropathy (SpA) , including 385 men. Thirty-six cases were diagnosed as sclerosing osteitis. Ten cases were diagnosed as sacroiliac joint degeneration. Ten cases were diagnosed as pyogenic sacroiliitis or sacroiliac joint tuberculosis. Four cases were diagnosed as diffuse idiopathic bone hypertrophy. Four cases were diagnosed as palmoplantar pustulosis arthritis. Four cases were diagnosed as metabolic bone disease. One case was diagnosed as sacroiliac joint gout. Four cases were diagnosed as neoplastic disease. HLA-B27 positive rate was 86.9% in AS/SpA. Erythrocyte sedimentation rate and C-reactive protein were increased mildly-to-moderately in AS/SpA patients. Erythrocyte sedimentation rate and C-reactive protein increased obviously in sacroiliac joint infection and tumor diseases. Imaging characteristics were sacroiliac joint bone destruction. Magnetic resonance imaging showed sacroiliac joint bone marrow edema, but range was not beyond anatomical structure in AS/SpA.

Based on disease distribution of sacroiliitis, AS/SpA is predominant while non-ankylosing spondylitis is not uncommon. Differential diagnoses of sacroiliitis should be considered to avoid malpractice, especially in patients with negative HLA-B27.