Spondyloarthritis refers to a range of inflammatory MSK conditions with shared features which can affect both the spine and peripheral joints.3
Psoriatic arthritis typically affects the small joints of the hands and feet (and sometimes finger and toe joints) and/or the large joints, especially the knees. However, it can also develop in the spinal axial joints.
Axial spondyloarthritis (axial SpA) is an umbrella term for painful, progressive inflammatory arthritis affecting the spine. It includes ankylosing spondylitis where changes in the sacroiliac region can be seen on x-rays, and non-radiological axial SpA where symptoms indicate there are sacroiliac changes which do not appear on x-rays but can show up on MRI scans.4
Axial SpA symptoms typically start in the late teens or early 20s, although 5 per cent of cases start in people over the age of 45. While non-radiological axial SpA occurs equally in men and women, men are more likely to develop the structural changes seen in ankylosing spondylitis. Unfortunately, the average time to diagnosis from initial symptoms is 8.5 years, meaning irreversible damage can have occurred. Smoking can exacerbate the condition.
Axial SpA, and sometimes psoriatic arthritis, involves inflammation where ligaments or tendons attach to the bone (enthesis) followed by the bone degrading (enthesopathy). As the inflammation subsides, new bone growth occurs, but movement is lost as the bone replaces the ligaments or tendons. Vertebrae can eventually fuse. The HLA-B27 gene is implicated but is not the only likely cause.3,4
Bone mineral density loss (seen in up to 62 per cent of cases), osteoporosis, fragility fractures and depression are often co-morbidities in axial SpA. Quality of life impacts includes pain, stiffness and poor sleep.4
Sometimes the eyes and bowel are also affected. Spondyloarthritis also includes conditions such as Crohn’s disease, ulcerative colitis and reactive arthritis where peripheral arthritis occurs after a gastrointestinal or genitourinary infection.3