A back pain that eases with exercise and worsens with rest
Most sore backs want rest. Ankylosing spondylitis does the opposite: the pain is often worst when still, wakes people in the early morning, and can ease with movement. This inflammatory arthritis of the spine usually starts between 20 and 30 and is tightly linked to a single immune gene variant.
The name stitches together Greek words for curved, vertebra and inflammation. It is a form of axial spondyloarthritis, a long-running inflammation of spinal joints that typically centres on the point where the spine meets the pelvis. Somewhere between 0.1 and 0.8 percent of people have it. Men and women are affected equally, though women tend to show inflammation rather than fusion of the joints.
It usually creeps in gradually, as a dull ache and stiffness in the lower back or buttocks. Over time, flexibility of the lumbar spine and even the ability to expand the chest can shrink, and weight loss, fever and fatigue are common companions. Pain may spread to a buttock or the back of the thigh, and hips and shoulders can be drawn in. When it starts before 18, large leg joints like the knees are more often involved.
This is a whole-body disease. Roughly 30 percent of patients develop anterior uveitis, an eye inflammation causing pain, redness and blurred vision. The aorta and heart valves can become inflamed, and the upper lungs may slowly scar. Because tests find no rheumatoid factor, it is classed as seronegative.
Genes and environment both play a role, and the mechanism is thought to be autoimmune or autoinflammatory. In the UK more than 90 percent of patients carry the HLA-B27 antigen, though only 70 percent do in Turkey, and just 1 to 2 percent of HLA-B27 carriers ever develop the disease. A variant near the PTGER4 gene, which governs a receptor that promotes bone deposition, has also been tied to higher risk. Diagnosis rests on symptoms backed by imaging and blood tests. As of 2019 there was no cure; care combines medicines such as NSAIDs and TNF inhibitors with physical therapy and sometimes surgery, aiming to ease symptoms and slow progression.
Source: Ankylosing spondylitis
