A Road Map of the Axial Spondyloarthritis Continuum

Axial spondyloarthritis (axSpA) is a chronic, immune-mediated inflammatory disease characterized by inflammatory low back pain, inflammation in peripheral joints and entheses, and other extra-articular or systemic manifestations. Although our understanding of the natural history of axSpA has been limited by incomplete knowledge of disease pathogenesis, axSpA is increasingly understood as a spectrum of axial, peripheral, and extra-articular inflammatory conditions that includes nonradiographic axSpA and radiographic axSpA, also known as ankylosing spondylitis. In this narrative review, we present a road map of this axSpA continuum, highlighting genetic risk factors for the development of axSpA, triggers of disease, and reasons for and implications of diagnostic delay. We present a detailed overview of the spectrum of axSpA clinical manifestations and highlight factors known to influence the risk of disease progression. Finally, we provide some expert commentary on the practical use of this road map to assist health care providers in the identification of axSpA in clinical practice.