Diffuse Idiopathic Skeletal Hyperostosis versus Ankylosing Spondylitis: Brief Case Review

Diffuse Idiopathic Skeletal Hyperostosis versus Ankylosing Spondylitis: Brief Case Review D idiopathic skeletal hyperostosis is an idiopathic form of degenerative arthritis. It is usually characterized by exuberant bony growth along the anterior longitudinal ligament and typically affects males over 60 years of age. Diffuse idiopathic skeletal hyperostosis, previously known as Forestier’s disease, is the most common enthesopathy. In 1950 it was originally described by Forestier and Rotes-Querol as a senile ankylosing hyperostosis of the spine. This condition is associated with extraaxial involvement (i.e., ossification of the nuchal ligament or tendons in the extremities). Patients with this diagnosis can suffer from heel spurs or ligamentous calcification at the elbow or knee. The other spinal enthesopathies are OPLL and OVAL. Diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis are cervical ankyloses that can be difficult to distinguish from one another. Pathologically, diffuse idiopathic skeletal hyperostosis differs from ankylosing spondylitis. Clinically, however, both are similar. Diffuse idiopathic skeletal hyperostosis has even been referred to as a “senile ankylosing spondylitis.” Ankylosing spondylitis, a chronic inflammatory rheumatic disease, tends to affect relatively young white males. Classically, it is associated with sacroiliac and/or apophyseal fusion or sclerosis. Patients with ankylosing spondylitis are symptomatic and suffer from a myriad of associated conditions such as iritis, uveitis, or ulcerative colitis. In contrast, patients with diffuse idiopathic skeletal hyperostosis tend to be asymptomatic. However, findings such as dysphagia from esophageal impingement, spinal cord compression, and peDiffuse idiopathic skeletal hyperostosis is sometimes confused with ankylosing spondylitis. We present a case of diffuse idiopathic skeletal hyperostosis and describe its clinical management and the characteristics that may help differentiate this entity from ankylosing spondylitis. Clinicians must be aware of overlapping characteristics between these two disease processes and be able to distinguish between the two because the course of their treatment is considerably different. Key criteria for excluding ankylosing spondylitis and diagnosing diffuse idiopathic skeletal hyperostosis are the absence of sacroiliac fusion, erosion, or sclerosis, which can be determined by obtaining a plain x-ray of the pelvis.