Abstract
Axial spondyloarthritis encompasses both radiographic axial spondyloarthritis (previously known as ankylosing spondylitis) and nonradiographic axial spondyloarthritis. The distinction is mainly based on the presence or absence of plain x-ray changes of sacroiliitis sufficient to fulfill that part of the modified New York criteria for ankylosing spondylitis. Even so, imaging (mainly with magnetic resonance imaging or computed tomography) still plays a critical role in the diagnosis of this disorder. In addition to HLA-B27 genetic markers for axial SpA now include at least 116 known genetic loci, particularly aminopeptidase genes, IL-23 pathway genes, and lymphocyte development and activation genes. A polygenic risk score has been developed for axial spondyloarthritis and this may be helpful for early diagnosis. A regular exercise program and physical therapy remain important components of the treatment program. But effective monoclonal antibody drugs that inhibit TNF or IL-17 represent major therapeutic advances. TNF inhibitors may be preferred for patients with concomitant anterior uveitis whereas IL-17 inhibitors may be preferred for patients with concomitant psoriasis. Janus kinase inhibitors are also effective treatment for axial spondyloarthritis.