Axial skeletal changes in paralysed patients may mimic ankylosing spondylitis.

Patients with paralysis may develop radiographic changes in the axial skeleton and sacroiliac joints that resemble those seen in ankylosing spondylitis. These similarities can result in confusion when evaluating paralysed patients with back pain. We report on a patient with paralysis secondary to amyotrophic lateral sclerosis who developed back pain, apparent sacroiliac joint fusion, and a 'bamboo spine', leading to the misdiagnosis of ankylosing spondylitis. Serial radiographs of the bony changes in our patient are presented, along with a brief review of the literature on axial skeletal abnormalities in paralysis and a discussion of the subtle changes that distinguish immobilization spondyloarthropathy from ankylosing spondylitis.