Ankylosing spondylitis is one of many forms of inflammatory arthritis, the most common of which is rheumatoid arthritis. Ankylosing spondylitis primarily causes inflammation of the joints between the vertebrae of your spine and the joints between your spine and pelvis (sacroiliac joints). However, ankylosing spondylitis may also cause inflammation and pain in other parts of your body :
- Where your tendons and ligaments attach to bones
- Joints between your ribs and spine
- Joints in your hips, shoulders, knees and feet
- Your eyes
As ankylosing spondylitis worsens and the inflammation persists, new bone forms as a part of the body's attempt to heal. Your vertebrae begin to grow together, forming vertical bony outgrowths (syndesmophytes) and becoming stiff and inflexible. Fusion can also stiffen your rib cage, restricting lung capacity and function.
Also called spondylitis or rheumatoid spondylitis, ankylosing spondylitis is a chronic condition. Treatments can decrease your pain and lessen your symptoms. Effective treatment may also help prevent complications and physical deformities.
Ankylosing spondylitis has no known specific cause, though genetic factors seem to be involved. In particular, people who have a gene called HLA-B27 are at significantly increased risk of developing ankylosing spondylitis.
Risk Factor :
Genetics may play a role in the development of ankylosing spondylitis. In fact, the majority of people with this condition have the HLA-B27 gene. Having this gene doesn't mean that you'll acquire ankylosing spondylitis — no more than 2 percent of people with this gene develop the condition — but it may make you more susceptible to the disease.
If you test positive for the HLA-B27 gene, are younger than 40 and have a family member with ankylosing spondylitis, you have about a one in five chance of developing the condition. However, if you're older than 40, your chances of acquiring ankylosing spondylitis are low. If you have ankylosing spondylitis, you have about a 50 percent chance of passing the HLA-B27 gene on to your children if you have the gene.
Ankylosing spondylitis affects males more often, and its onset generally occurs between the ages of 16 and 40. In the United States, ankylosing spondylitis is most common among some American Indian tribes.
When to seek medical advice :
See your doctor if you have symptoms of ankylosing spondylitis. Also contact your doctor if you're being treated for the disease and new signs and symptoms develop.
Your condition may change over time, with symptoms getting worse, improving or completely stopping at any point. Early signs and symptoms may include pain and stiffness in your lower back and hips — which is often worse in the morning, at night and after periods of inactivity. Over time, the pain and stiffness may progress up your spine and to other joints, such as those in your hips, shoulders, knees and feet.
In advanced stages, the following signs and symptoms may develop :
- Restricted expansion of your chest
- Chronic stooping
- Stiff, inflexible spine
- Loss of appetite
- Weight loss
- Eye inflammation (iritis)
- Bowel inflammation
Diagnosis of ankylosing spondylitis may be delayed if your symptoms are mild or if you mistakenly attribute some of your symptoms to more common back problems.
To determine the cause of your discomfort, your doctor will conduct a medical history and complete a physical examination. Then, your doctor may use the following diagnostic procedures :
- X-rays or other imaging. X-rays allow your doctor to check for changes in your joints and bones, though the characteristic effects of ankylosing spondylitis may not be evident early in the disease. Your doctor may also use other imaging tests, such as computerized tomography (CT) or magnetic resonance imaging (MRI) scans, to detect inflammation and other changes in your joints.
- Blood tests. Your doctor may check for indications of inflammation using one or more blood tests, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). In the ESR test, inflammation is signaled by elevation in the speed at which your red blood cells settle to the bottom of a tube of blood in one hour. The CRP test indicates inflammation by the presence of a protein that your liver produces as part of your immune system response to injury or infection.
Other tests used to diagnose ankylosing spondylitis include a complete blood count (CBC) to determine if you have anemia, a condition in which there aren't enough healthy red blood cells to carry adequate oxygen to your tissues. Anemia is a complication that can result from the chronic inflammation of ankylosing spondylitis. Finally, your doctor may check your blood for the HLA-B27 gene. The presence of this gene doesn't determine whether you have ankylosing spondylitis. But its absence makes it less likely that you do.
Ankylosing spondylitis doesn't follow a set course. The severity of symptoms and development of complications vary widely among individuals. Complications may include :
- Difficulty walking or standing. Typically, ankylosing spondylitis begins with soreness in your lower back. As the disease progresses, the affected bones may fuse together, rendering your joints immobile and causing a stiff, inflexible spine (bamboo spine). This can make walking or standing difficult. Your joints may fuse even if you undergo proper treatment — and once joints fuse, additional treatment won't help restore mobility. However, if fusion occurs with your spine in an upright position, you can remain more able to perform activities of daily living.
- Difficulty breathing. Inflammation can also spread up your spine and cause the bones in your rib cage to fuse. This results in breathing problems. When your ribs can't move when you breathe, it's difficult to fully inflate your lungs. However, if you don't have an unrelated lung condition, you may be able to continue your everyday activities without experiencing shortness of breath.
- Heart problems. If the inflammation reaches your heart, you can develop valve problems, such as inflammation of the body's largest artery (aorta), also known as aortitis. Another possible complication is aortic valve regurgitation, which occurs when the aortic ring and aortic valve are distorted.
- Lung infections. In some people with ankylosing spondylitis, cavitary lesions develop in the upper portion of the lungs. These cavities can slowly enlarge over many years and develop infections, most commonly fungal infections.
Inflammation can also involve other parts of your body, resulting in conditions such as :
- Inflammatory bowel disease
- Painful and inflamed eyes (iritis)
The goal of treatment is to relieve pain and stiffness, and prevent or delay complications and spinal deformity. Ankylosing spondylitis treatment is most successful early, before it causes irreversible damage to your joints, such as fusion, especially in positions that limit your function.
Your doctor may recommend that you take one or more of the following medications :
- Nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs — such as naproxen (Aleve, Naprosyn) and indomethacin (Indocin) — are the medications doctors most commonly use to treat ankylosing spondylitis. They can relieve your inflammation, pain and stiffness.
- Disease-modifying antirheumatic drugs (DMARDs). Your doctor may prescribe a DMARD, such as sulfasalazine (Azulfidine) or methotrexate (Rheumatrex), to treat inflamed joints of the legs and arms and other tissues. This class of drugs helps limit the amount of joint damage that occurs.
- Corticosteroids. These medications, such as prednisone, may suppress inflammation and slow joint damage in severe cases of ankylosing spondylitis. You usually take them orally, ideally for a limited period of time because of their side effects. Occasionally, corticosteroids are injected directly into a painful joint.
- Tumor necrosis factor (TNF) blockers. Doctors originally used TNF blockers to treat rheumatoid arthritis. TNF is a cytokine, or cell protein, that acts as an inflammatory agent in rheumatoid arthritis. TNF blockers target or block this protein and can help reduce pain, stiffness, and tender or swollen joints. These medications, such as adalimumab (Humira), etanercept (Enbrel) and infliximab (Remicade), may decrease inflammation and improve pain and stiffness for people with ankylosing spondylitis.
Physical therapy can provide a number of benefits, from pain relief to improved physical strength and flexibility. Your doctor may recommend that you meet with a physical therapist to provide you with specific exercises designed for your needs.
Range-of-motion and stretching exercises can help maintain flexibility in your joints and preserve good posture. In addition, specific breathing exercises can help to sustain and enhance your lung capacity.
As your condition worsens, your upper body may begin to stoop forward. Proper sleep and walking positions and abdominal and back exercises can help maintain your upright posture. Though you may develop spine stiffness despite your treatment, proper posture can help to ensure that your spine is fused in a fixed upright position.
Most people with ankylosing spondylitis don't need surgery. However, your doctor may recommend surgery if you have severe pain or joint damage, or if a nonspinal joint is so damaged that it needs to be replaced. Spinal surgery is only rarely required.
Because genetic factors appear to play a part in ankylosing spondylitis, it's not possible to prevent the disease. However, being aware of any personal risk factors for the disease can help in early detection and treatment. Proper and early treatment can relieve joint pain and help to prevent or delay the onset of physical deformities.