Clinical Pearls & Morning Reports
Published September 4, 2019
Extraintestinal manifestations of Crohn’s disease include axial or peripheral arthritis, uveitis, psoriasis, erythema nodosum, pyoderma gangrenosum, and, uncommonly, aseptic diskitis and necrobiotic pulmonary nodules. Read the Clinical Problem-Solving article here.
Q: What is axial spondyloarthritis?
A: Spondyloarthritis describes a family of diseases that are characterized by chronic inflammation affecting the axial joints (spine, pelvis, and thoracic cage), peripheral joints (arms and legs), or both. When the axial joints are predominantly involved, the condition is called axial spondyloarthritis; its prototype is ankylosing spondylitis, which is characterized by radiographic evidence of sacroiliitis.
Q: What is peripheral spondyloarthritis?
A: Peripheral spondyloarthritis primarily involves peripheral joints; its prototype is psoriatic arthritis, which is characterized by psoriatic skin lesions, synovitis, enthesitis, and dactylitis. Reactive arthritis, which is triggered by antecedent infection, is another spondyloarthritis that is typically peripheral. Spondyloarthritis in patients with inflammatory bowel disease can be predominantly axial or peripheral.
A: Inflammatory back pain is the hallmark of axial spondyloarthritis and is characterized by an insidious onset (typically before 40 years of age), morning stiffness lasting longer than 30 minutes, alleviation with exercise but not rest, and nocturnal pain that awakens the patient. The most common extraarticular manifestation of axial spondyloarthritis is anterior uveitis, which is typically associated with HLA-B27. Rarely, aseptic diskitis can accompany inflammatory spondyloarthritis. Aseptic diskitis in axial spondyloarthritis (Andersson’s lesions) can arise through two mechanisms. The first is a fracture of the bridging syndesmophytes with a resultant pseudoarthrosis (false joint) and inflammation of the intervening disk. The second is a primary inflammatory diskitis associated with axial spondyloarthritis (collectively termed spondylodiskitis).
A: In a patient with at least 3 months of inflammatory back pain, plain radiography may show sacroiliitis (with a sensitivity of 48%, as shown in a single-cohort study). If plain radiographs are negative, T1-weighted MRI of the pelvis or symptomatic spinal area can show sacroiliitis or spondylitis, respectively (with a sensitivity of 85%). Fluid-sensitive MRI sequences (e.g., T2-weighted with short-tau inversion recovery [STIR]) are required for detecting spinal inflammation.