Axial spondyloarthritis—current aspects

Axial spondyloarthritis (axSpA) is a frequent inflammatory rheumatic disease mainly affecting the axial skeleton causing inflammatory back pain. If chronic inflammation persists new bone formation may occur possibly leading to irreversible spinal stiffness. The disease has a strong genetic background with HLA-B27 as the major factor. For diagnostic purposes, imaging is of critical importance—especially conventional radiography and magnetic resonance imaging (MRI). While the former has advantages in the detection of bony changes such as the syndesmophytes, MRI is used to detect axial inflammation but also erosions in the sacroiliac joint. Treatment follows the treat-to-target strategy starting with non-steroidal anti-inflammatory drugs (NSAIDs) in the first line, and later, if high disease activity persists, therapy with biologic disease modifying anti-rheumatic drugs (bDMARDs) is according to international recommendations indicated. For the treatment of axSpA, important targets such as tumor necrosis factor alpha (TNFα) and interleukin (IL)-17 have been identified, and several of their inhibitors (i) including some biosimilars for the former have been approved. Recently, also inhibition of Janus kinases was shown to be efficacious. There is evidence that long term inhibition of inflammation with TNFi can reduce bone formation.