Current Concepts and Medical Management for Patients with Radiographic Axial Spondyloarthritis

Abstract

Radiographic axial spondyloarthritis (r-axSpA), a chronic inflammatory disease, can cause significant radiographic damage to the axial skeleton. Regarding the pathogenic mechanism, association of r-axSpA with tumor necrosis factor (TNF) and the interleukin-23/17 (IL23/ IL17) pathway has been reported. Development of extraarticular manifestations, including uveitis, inflammatory bowel disease, and psoriasis, has been reported in some patients. The pivotal role of human leukocyte antigen-B27 in the pathogenesis of r-axSpA remains to be clarified. Symptoms usually start in late adolescence or early adulthood, and disease progression can vary in each patient, with clinical manifestations ranging from mild joint stiffness without radiographic changes to advanced manifestations including complete fusion of the spine, and severe arthritis of the hip, and could include peripheral arthritis and extraarticular manifestations. The modified New York criteria was used previously in diagnosis of r-axSpA. However, early diagnosis of the disease prior to development of bone deformity was required due to development of biological agents. As a result of Assessment of SpondyloArthritis international Society (ASAS), the classification was improved in part for diagnosis of spondyloarthritis prior to development of bone deformity. The diagnosis is based on comprehensive laboratory findings, physical examinations, and radiologic findings. Medical treatment for r-axSpA involves the use of a stepwise strategy, starting with administration of nonsteroidal anti-inflammatory drugs and physiotherapy, and progressing to sulfasalazine or methotrexate and biologics including TNF-α inhibitors or IL-17 inhibitors as needed. Use of Janus kinase inhibitors has been recently reported.

Keywords: Ankylosing spondylitis; Axial spondyloarthritis.

Fig. 1

Proposed hierarchy of cytokine participation in disease pathogenesis in affected tissues in spondyloarthritis, based on the therapeutic response in clinical trials for biologic agents targeting the indicated cytokines¹²⁾. TNF: tumor necrosis factor, IL: interleukin.

Fig. 2

Radiographs of severe arthritis of the hip with limited hip motion on both sides in a radiographic of axial spondyloarthritis.

Fig. 3

Posture in patients with radiographic axial spondyloarthritis compared with that in a normal subject.

Fig. 4

Land-marking method for the Schober test (ST), the modified Schober’s test (MST) and the modified-modified Schober’s test (MMST)³²⁾. When using Shober’s test, the range of spinal flexion is defined as the increase in the distance between the lumbosacral junction and a point located 10 cm above it. When using the MST, the reference point is located 10 cm above and 5 cm below the lumbosacral junction. When using the MMST, a line is drawn between two posterior superior iliac spines (PSIS) and a landmark on the spine at 15 cm to obtain the overall lumbar spine flexion. E: extension, F: flexion.

Fig. 5

Progressive ossification with marginal syndesmophytes as bony bridges connecting successive vertebral bodies on a simple X-ray. (A) Lumbar. (B) Cervical spine.

Fig. 6

Active sacroiliitis shown on a short tau inversion recovery magnetic resonance imaging sequence in the ileum and in the upper part of the sacrum of the right sacroiliac joint.

Fig. 7

Features observed on the spine between radiographic axial spondyloarthritis (A) and DISH (diffuse idiopathic skeletal hyperostosis) (B).

Fig. 8

Features observed in the sacroiliac joint between radiographic axial spondyloarthritis (A) and osteitis condensans ilii (B).

Fig. 9

Main recommendations for treatment of patients with active ankylosing spondylitis. Adapted from the article of Ward et al. (Arthritis Rheumatol. 2019;71:1599-613)⁴¹⁾ with original copyright holder’s permission. AS: ankylosing spondylitis, NSAIDs: nonsteroidal anti-inflammatory drugs, SSZ: sulfasalazine, MTX: methotrexate, TNFi: tumor necrosis factor-α inhibitor, TOF: tofacitinib, SEC: secukinumab, IXE: ixekizumab, IBD: inflammatory bowel disease, MRI: magnetic resonance imaging.

Fig. 10

Main recommendations for treatment of patients with stable ankylosing spondylitis. Adapted from the article of Ward et al. (Arthritis Rheumatol. 2019;71:1599-613)⁴¹⁾ with original copyright holder’s permission. AS: ankylosing spondylitis, NSAIDs: nonsteroidal anti-inflammatory drugs, TNFi: tumor necrosis factor-α inhibitor, SSZ: sulfasalazine, MTX: methotrexate.

Fig. 11

ASAS (Assessment of SpondyloArthritis international Society)-EULAR (European Alliance of Associations for Rheumatology) recommendations. Adapted from the article of Ramiro et al. (Ann Rheum Dis. 2023;82:19-34)⁴²⁾ with original copyright holder’s permission. NSAIDs: nonsteroidal anti-inflammatory drugs, ASDAS: Ankylosing Spondylitis Disease Activity Score, TNFi: tumor necrosis factor-α inhibitor, IL: interleukin, JAKi: Janus kinase inhibitor, IBD: inflammatory bowel disease, Ab: antibody, bDMARDs: biologic disease-modifying anti-rheumatic drugs.