Non-Radiographic Axial Spondyloarthritis (nr-axSpA): Advances in Classification, Imaging and Therapy.

Non-radiographic axial spondyloarthritis (nr-axSpA) is a recently described form of axial inflammatory arthritis that has not caused substantial erosive damage to the sacroiliac joints. Nr-axSpA is associated with significant impairment in quality of life and, in a proportion of patients, it can evolve into ankylosing spondylitis (AS, also termed radiographic axSpA). The identification in the clinic of nr-axSpA has been made possible by advances in magnetic resonance imaging (MRI). Classification criteria for nr-axSpA have been proposed but there remains discussion in the international community regarding this. Studies are ongoing to further define the classification and diagnosis of nr-axSpA. There is much further research required regarding the optimal use of MRI in nr-axSpA, including distinguishing sacroiliac MRI changes in the normal population and the definition of a positive MRI in spinal disease. Non-steroidal anti-inflammatory drugs and physiotherapy are the core first-line therapy for nr-axSpA. Tumour necrosis factor inhibitors also play a very important role in treatment of patients with active nr-axSpA who do not respond to first-line therapy. Agents directed at interleukin-17, interleukin-23 and Janus kinase inhibitors are proving effective in AS with ongoing and planned studies in nr-axSpA. A great deal of active research is being undertaken in classification, imaging and therapy in nr-axSpA and so the future for improving the lives of patients with nr-axSpA is promising.