Nonradiographic axial spondyloarthritis

Non-radiographic axial spondyloarthritis (nr-axSpA) is a complex disease process that is part of the spectrum of axial spondyloarthritis (axSpA). This article reviews the current state of the literature as the understanding of this disease spectrum expands. The conceptual history and terminology, genetics, and epidemiology are reviewed. The clinical manifestations, diagnostic approach, and measures of disease activity are examined. Finally the current treatment modalities and recommendations and the research agenda for nr-axSpA are reviewed. With the advent of new criteria, the disease spectrum can be studied in a systematic manner. These data have enriched our knowledge that reflects an earlier or milder form of disease on a spectrum same as that of ankylosing spondylitis (or radiographic axSpA). We learned how patients present in this stage and that despite an unacceptable delay in diagnosis (regardless of the stage), the burden of disease is high and unremitting. nr-axSpA clinical trials have been somewhat heterogeneous (with variable inclusion criteria) but have nevertheless shown considerable efficacy with tumor necrosis factor inhibitors and flare on withdrawal of therapy.