Ankylosing spondylitis is a form of arthritis that primarily affects your spine. It causes severe inflammation of the vertebrae that might eventually lead to chronic pain and disability. In more advanced cases, the inflammation can cause new bone to form on the spine. This may lead to deformity. Ankylosing spondylitis can also cause pain and stiffness in other parts of your body. Other large joints, such as the shoulders, hips, and knees, can be involved as well.
What are the Causes of ankylosing spondylitis?
The symptoms of ankylosing spondylitis vary. It’s often characterized by mild to moderate flare-ups of inflammation that alternate with periods of almost no symptoms.The most common symptom is back pain in the morning and at night. You may also experience pain in the large joints, such ankylosing spondylitis the hips and shoulders. Other symptoms may include:
- early morning stiffness
- poor posture or stooped shoulders
- loss of appetite
- low-grade fever
- weight loss
- anemia or low iron
- reduced lung function
As mentioned above, some researchers believe that particular kinds of bacteria attack the body and cause inflammation around the ligaments. HLA-B27 potentially has something to do with this, but more research is needed to confirm the connection. That inflammation—and especially chronic inflammation like in causes of ankylosing spondylitis—can cause the body to release chemicals that can harm surrounding tissues, such as the cartilage. The damaged tissue is replaced by scar tissue, which can cause more pain since it doesn’t protect the joint, as well as cartilage, does. The scar tissue can then harden and form new bone as a result of ankylosing spondylitis’ effect on the body.
There are a number of conditions related to ankylosing spondylitis which have many similar symptoms:
- Non-radiographic ankylosing spondylitis and undifferentiated spondyloarthritis (uSpA) have similar symptoms to ankylosing spondylitis but x-rays won’t show the signs of damage to your joints. Sometimes people with these conditions are later diagnosed with ankylosing spondylitis.
- Psoriatic spondyloarthritis is a form of psoriatic arthritis which occurs in association with the skin condition psoriasis.
- Spondyloarthritis associated with inflammatory bowel disease (or enteropathic arthritis) is related to bowel conditions such as Crohn’s disease or ulcerative colitis.
- Reactive arthritis (which used to be known ankylosing spondylitis Reiter’s syndrome) is diagnosed when your arthritis is a reaction to an infection.
- Enthesitis-related arthritis is the name used when children and teenagers develop arthritis of the entheses, the sites where tendons and ligaments attach to bone.
In a minority of individuals, pain does not start in the lower back or even the neck, but in a peripheral joint such as the hip, ankle, elbow, knee, heel, or shoulder. This pain is commonly caused by enthesitis, inflammation of the site where a ligament or tendon attaches to the bone. Inflammation and pain in peripheral joints are more common in juveniles with causes of ankylosing spondylitis. This can be confusing since, without the immediate presence of back pain, AS may look like some other form of arthritis.