Ankylosing spondylitis, also called radiographic axial spondyloarthritis, is an inflammatory disease caused by the body’s immune system attacking its tissues, primarily the bones of the spine. If left untreated, the inflammation in AS can cause damage to joints, muscles, tendons, and other parts of the body.
Although ankylosing spondylitis symptoms vary greatly from person to person, lower back pain is the most common symptom. AS is caused by inflammation of the spinal joints, and people with the condition typically present with back pain. Symptoms are generally worse after periods of rest or immobility, such as sleeping, and they improve with movement and activity.
Ankylosing spondylitis causes inflammation of the vertebra (joints in the spine). Inflammation is a process within the body that is usually helpful. It’s the body’s way of healing injury and fighting infection. During inflammation, the immune system increases blood flow to the affected area and allows fluid to build up, which helps flush out any germs or foreign particles.
In some health conditions, including ankylosing spondylitis, the immune system mistakenly attacks healthy cells within the body. This leads to chronic (ongoing) inflammation that can damage tissues and affect the body in many ways.
In people with ankylosing spondylitis, a cycle of inflammation and repair occurs in the ligaments, tendons, and joints of the back. This process causes scarring in these tissues. Over time, chronic inflammation can lead to bones fusing together in a process known as ankylosis. Sections of the spine fuse together, causing a person to become stiff and immobile. Eventually, ankylosing spondylitis can lead to pain, decreased flexibility, and posture problems.
Not everyone with ankylosing spondylitis will develop fusions, but AS can put a person at an increased risk for spinal fractures because the spine becomes stiffer and has less range of motion with the new, weaker bone formation.
Some people with ankylosing spondylitis develop complications in other parts of the body. Although it is primarily a disease of the spine, AS can affect other organs, such as the eyes, heart, digestive system, and muscles.
Over time, ankylosing spondylitis can affect other joints outside of the spine. Most joints have small amounts of synovial fluid, which helps lubricate the joints and support healthy cartilage. When joints experience inflammation, the amount of synovial fluid increases. This process can lead to pain and swelling.
About 1 out of 3 people with ankylosing spondylitis have inflammation in the hips or shoulders. These joints may feel painful, and the pain can sometimes radiate out to nearby areas such as the knees. People who experience pain in the sacroiliac joint (hip) may be more likely to have a more severe condition.
Jaw problems affect around 15 percent of people with ankylosing spondylitis. This can have a significant effect on a person’s quality of life. Some people with this condition have trouble chewing or swallowing.
Many people with ankylosing spondylitis also have problems with their ribs and other bones that make up the chest. The fusion of spinal sections often leads to a rounding of the spine, called kyphosis. This can cause the rib cage to stiffen and make it more difficult for the chest to expand properly while breathing.
Many people with AS experience costochondritis, which can cause chest pain that can be mistaken for cardiovascular problems. Costochondritis is an inflammation of the cartilage in the ribs, but it can feel like intense chest pain. One MySpondylitisTeam member said, “My sternum hurts — and above my diaphragm.”
This condition is not dangerous and usually goes away on its own. However, symptoms can be managed with medication, physical therapy, and exercise.
When the entheses (areas where ligaments, joint capsules, and tendons attach to bone) become inflamed, the inflammation is known as enthesitis. The inflamed areas become very painful and are known as “hot spots.” Enthesitis may commonly be felt as pain in the foot or heel. Muscles around areas of enthesitis can become weaker due to pain and disuse.
Kyphosis can also cause the muscles of the heart and lungs to weaken, as they cannot expand as much as they once could. In addition, the postural muscles — which help control balance, endurance, and coordination — can become weaker.
About half of people with ankylosing spondylitis will develop eye inflammation, also called iritis or uveitis. Eye inflammation can lead to serious damage to the eyes or even blindness. It requires immediate evaluation by a doctor.
Symptoms of iritis include eye pain, red eyes, blurry vision, and sensitivity to light. If you notice any of these symptoms, seek advice from an ophthalmologist or optometrist right away.
Inflammatory bowel disease affects about 6 percent to 14 percent of people with ankylosing spondylitis. Many people with ankylosing spondylitis have inflammation throughout the digestive system, although they have not been diagnosed with IBD.
IBD consists of two different disorders: Crohn’s disease and ulcerative colitis. IBD causes ongoing inflammation in the digestive tract, leading to symptoms like pain, diarrhea, and blood in the stool.
Researchers are still studying why there is a link between ankylosing spondylitis and IBD. Genetics may play a role. Additionally, people with ankylosing spondylitis often have changes in the types of bacteria that live in the digestive system, which may lead to disease. Researchers also think IBD may lead to changes in immune cells in the digestive system. These altered immune cells may then travel to the joints and create inflammation there.
Between 2 percent and 10 percent of people living with ankylosing spondylitis are estimated to have heart complications, which may occur before the typical symptoms of AS appear. Cardiovascular issues may include:
Ankylosing spondylitis can eventually lead to cauda equina syndrome, a complication that affects the nerves. During cauda equina syndrome, inflammation causes scarring in the nerves at the base of the spinal cord. This nerve damage may lead to:
If you are concerned about developing these complications of ankylosing spondylitis, ask your health care team about ways to lower your risk.
Until recently, spondylitis was thought to mainly affect men. In the past few years, researchers have realized that this form of inflammatory arthritis develops equally often in women, and it can affect women in different ways. Women may be less likely to display the signature bone damage of ankylosing spondylitis on X-rays. Compared with men, women with spondylitis are more likely to experience:
Ankylosing spondylitis tends to develop during the teenage years or early adulthood, so women are likely living with the condition during their childbearing years. Compared with women who don’t have the disease, those who do are may be more likely to:
Certain treatments for spondylitis may not be safe to take during pregnancy or while breastfeeding. Women with spondylitis who are planning a family should work closely with their rheumatologist and obstetrician to determine the best way to control symptoms during this period.
People with ankylosing spondylitis may receive several different treatments depending on which parts of the body are affected.
Treatment for fusing of the spine typically begins with managing symptoms using nonsteroidal anti-inflammatory drugs (NSAIDs). Your rheumatologist may prescribe disease-modifying antirheumatic drugs (DMARDs) such as biologics or methotrexate. Regular exercise and physical therapy can also help reduce stiffness and pain in the spine or muscles.
Medications and exercise can also help prevent symptoms in the joints. Ice packs and massage may help reduce pain and swelling. Deep breathing exercises can also help keep the bones in the chest flexible.
Treatment plans for eye inflammation associated with ankylosing spondylitis usually include topical corticosteroid drops and a dilating eye drop. In more severe cases, an injection of a corticosteroid may be used. Some tumor necrosis factor (TNF) inhibitors are also effective.
If you have IBD and spondylitis, your doctor may recommend you avoid NSAIDs, as these medications can make gastrointestinal symptoms worse. Many doctors prescribe biologics like TNF blockers or interleukin-17 inhibitors to treat ankylosing spondylitis and IBD.
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