Atypical Unilateral Sacroiliitis Secondary to Mechanical Stress Injury.

We report for the first time a case of atypical unilateral sacroiliitis secondary to mechanical stress injury. Unilateral sacroiliitis can be caused by a variety of etiologies. The first diagnosis to rule out is infection since it requires urgent treatment to avoid its serious consequences. Spondyloarthritis can be manifested by unilateral sacroiliitis in its early stage. Sacral fractures should always be looked for on the imaging modalities performed. In our case, no signs of infection or systemic disease were found. No fracture was seen on the imaging examinations and we had negative cultures on the computed tomography-guided biopsy realized. A history of mechanical stress was the only clue found suggesting the diagnosis of a probable stress related sacroiliitis. A thorough review of the literature will be provided stating the different causes of sacroiliitis described till now, with discussion of this new reported entity.