David T Yu, MD
Joachim Sieper, MD
Paul L Romain, MD
ANKYLOSING SPONDYLITIS OVERVIEW — Ankylosing spondylitis (AS) is a chronic inflammatory disease that causes pain in the back, neck, and sometimes the hips. The back is composed of multiple separate bones known as vertebrae. “Ankylosing” means joining together, and refers to an inflexibility between the vertebrae; “spondylitis” means inflammation of the vertebrae. Spondyloarthritis refers to a group of diseases that share a tendency to cause spondylitis and some of which also cause inflammation of other joints besides those of the spine.
This topic discusses the symptoms, diagnostic tests, possible complications, and treatment of one of the family of spondyloarthritis diseases, ankylosing spondylitis. It also discusses some of the diseases that are classified as subtypes of spondyloarthritis. Separate topic reviews are available that discuss some of the medications used to treat ankylosing spondylitis and exercises that can help people with ankylosing spondylitis to stretch and strengthen. (See “Patient information: Disease modifying antirheumatic drugs (DMARDs)” and “Patient information: Arthritis and exercise”.)
SPONDYLOARTHRITIS FAMILY OF ARTHRITIS — Spondyloarthritis is a family of arthritis, of which ankylosing spondylitis is the most common member. The other members are:
- Reactive arthritis
- Arthritis associated with psoriasis (psoriatic arthritis)
- Arthritis associated with inflammatory bowel diseases (ulcerative colitis or Crohn’s disease)
When a physician knows that a particular patient has spondyloarthritis, but does not fall into one of the groups above, a diagnosis of “undifferentiated spondyloarthritis” may be made. Spondyloarthritis has also been classified into “axial” and “peripheral” spondyloarthritis according to whether the involvement is mainly in the spine or in the extremities. Ankylosing spondylitis belong to the axial class of spondyloarthritis. Separate topic reviews discuss reactive arthritis, psoriatic arthritis, and inflammatory bowel diseases. (See “Patient information: Reactive arthritis (formerly Reiter syndrome)” and “Patient information: Psoriatic arthritis” and “Patient information: Ulcerative colitis” and “Patient information: Crohn’s disease”.)
ANKYLOSING SPONDYLITIS SYMPTOMS — The most common symptom of ankylosing spondylitis is pain in the low back and hips. Pain, stiffness, and limited mobility in other joints also occur in some patients. More detailed information is available separately. (See “Clinical manifestations of ankylosing spondylitis in adults”.)
Spinal pain — Spinal pain, almost always in the low back, is usually the first and most common symptom of ankylosing spondylitis. Back pain that occurs with ankylosing spondylitis generally has some of the following characteristics:
- Begins in early adulthood (age 20 to 30)
- Gradual onset (rather than sudden onset after an acute injury)
- Lasts longer than three months
- Worse after rest, (for example, in the morning)
- Improved with activity
- Wakes you up in the second half of the night
- Can cause morning stiffness lasting more than 30 minutes
- Can cause buttock pain that alternates between the left and right side
Limited spinal mobility — The flexibility of the back may be reduced. Putting on shoes and stockings may become difficult due to a limited ability to bend forward.
- Hip pain — Arthritis of the hips is relatively common in ankylosing spondylitis, causing pain in the groin or buttocks or difficulty walking.
- Shoulder pain — Inflammation of the tendon and bone may cause shoulder pain and limited mobility of the affected shoulder(s).
- Arthritis in other joints — Pain, stiffness, and swelling of other joints may occur. A single joint (monoarthritis) or a few joints (oligoarthritis) may be affected.
- Enthesitis — An enthesis is a region where a tendon or a ligament attaches to bone. Enthesitis (inflammation of an enthesis) is a symptom of spondyloarthritis. In addition to the spine, areas that may develop enthesitis include the elbow, heel, and the ribs. Enthesitis of the ribs causes pain of the chest, especially during a deep breath, coughing, and sneezing.
- Constitutional features — As with any chronic inflammatory disease, people with ankylosing spondylitis may be tired and feel unwell. Difficulty sleeping, caused by back or joint pain at night, may contribute to fatigue. Low-grade fevers and weight loss occurs in some patients.
- Other affected systems — Body systems other than the joints can be affected (see ‘Ankylosing spondylitis complications’ below).
ANKYLOSING SPONDYLITIS RISK FACTORS — Ankylosing spondylitis is three times more common in males than in females. It is usually diagnosed in young adults between age 20 and 30 years.
The disease can be more common in certain families. For example, a person’s risk of developing ankylosing spondylitis increases if a first-degree relative (parent, sibling, or child) has ankylosing spondylitis. The presence of a gene called HLA-B27 may also increase the risk of developing ankylosing spondylitis.
ANKYLOSING SPONDYLITIS DIAGNOSIS — The diagnosis of ankylosing spondylitis is based upon a combination of a patient’s symptoms, physical examination, and imaging tests. (See “Diagnosis and differential diagnosis of ankylosing spondylitis in adults”.)
Imaging tests — People with ankylosing spondylitis develop characteristic changes in the sacroiliac joints (the joint that connects the base of the spine [sacrum] and large pelvic bone [ilium]). These changes can be seen on x-ray images, although the changes take time to develop and may not be apparent until years after ankylosing spondylitis is diagnosed.
Imaging tests such as magnetic resonance imaging (MRI) are more sensitive than plain x-rays, and may be used if ankylosing spondylitis is suspected but not clearly seen on x-ray.
Other tests — There is no blood test that, by itself, is capable of definitively diagnosing or excluding ankylosing spondylitis. However, testing for a particular type of gene, HLA-B27, can be helpful in selected groups of patients. Ankylosing spondylitis is unlikely in a patient with a negative test for HLA-B27 who is white and of European descent. Ankylosing spondylitis is even less likely if x-rays and MRI are normal or show no changes to suggest ankylosis of the sacroiliac joint or inflammation in that area.
ANKYLOSING SPONDYLITIS COMPLICATIONS — Complications of ankylosing spondylitis are uncommon, with the exception of anterior uveitis.
Anterior uveitis — Uveitis, or inflammation of part of the eye, is the most common ankylosing spondylitis-related problem that does not involve joints. Uveitis causes pain in the eye, blurring of vision, and light sensitivity. Uveitis requires immediate medical attention and treatment with eye medications, but often resolves within several months.
Neurologic problems — The bones of the spine cover and protect the spinal cord and spinal nerves. People with ankylosing spondylitis are at an increased risk of spinal cord injury because the fused spine is more likely to fracture in the event of an accident. Such spinal injuries can cause compression of the spinal cord, which can result in changes in sensation and mobility below the level of compression.
Symptoms of spinal cord compression include a change or loss of sensation in the arms or legs, weakness, or difficulty controlling the bowels or bladder. If you notice any of these symptoms after an injury or accident, even a minor one, you need immediate medical attention to determine if you have a spinal fracture. If left untreated, such spinal cord injuries can lead to permanent paralysis.
- Fracture of vertebrae — Loss of bone strength (osteopenia or osteoporosis) can occur in people with ankylosing spondylitis, increasing the risk of fracture. The most common site of fracture in patients with ankylosing spondylitis is the lower part of the neck. Increased pain in the neck after an injury requires medical attention.
- Dislocation of the vertebrae — Sometimes the bones in the spine can become partially dislocated, a condition known as subluxation. If not recognized and stabilized, subluxation can lead to spinal cord compression.
- Cauda equina syndrome — This rare complication occurs in people with longstanding disease who have severe stiffening of the spine. The symptoms result from damage to the nerves in the lower back, and include abnormal sensation, problems with motor function, and difficulty with bladder and bowel control. Men may experience erectile dysfunction or impotence.
Cardiovascular disease — Some patients with ankylosing spondylitis have heart problems that are thought to be related to the disorder. Problems with the heart valves are sometimes seen; the most common problem is a leaking aortic valve (aortic regurgitation).
Pulmonary disease — Many people with ankylosing spondylitis are unable to expand the chest normally during breathing because of stiffness between the ribs and the spine. In some cases, changes in the lungs can result. This may or may not cause breathing problems.
Ulcerations in the bowel — Some people with ankylosing spondylitis will develop ulcerations in the lining of the bowels, although these ulcerations do not usually cause any symptoms.
EFFECTS OF ANKYLOSING SPONDYLITIS ON DAILY LIFE — Ankylosing spondylitis can affect daily life in various ways. Dressing, reaching, rising from a chair, getting up from the floor, standing, climbing steps, looking to the side or over the shoulder, exercising, and doing household or work-related tasks can become more difficult as a result of the limited joint and spinal motion in ankylosing spondylitis. These limitations can affect you and your family, and many people with ankylosing spondylitis will require assistance from family and friends.
ANKYLOSING SPONDYLITIS TREATMENT — Ankylosing spondylitis treatment is tailored for each individual, based on the characteristics and severity of the disease. Treatment may include any of the following. (See “Assessment and treatment of ankylosing spondylitis in adults”.)
Exercise — Exercise should be part of the treatment program for everyone with ankylosing spondylitis. It can include home exercises, individual or group exercise with a physical therapist, or physical therapy treatments (PT). Optimally, each patient should be evaluated and be given instructions by a physical therapist. The exercise should consist of posture training, deep breathing, back extension, and other stretching movements. (See “Patient information: Arthritis and exercise”.)
Information about exercises designed for people with ankylosing spondylitis is available on the following website: www.nass.co.uk/exercise/.
Safety issues — Because of the increased risk of serious spinal injury from slips and falls, people with ankylosing spondylitis should take care to avoid such mishaps. Some simple measures include limiting the use of alcohol. Pain relieving drugs (such as codeine and other narcotics) and sedatives (sleeping pills) should also be used cautiously, if at all, since these also increase the risk of falling. Contact sports and other high-impact activities should be avoided.
Shower or tub grab-bars and night-lights decrease the chance of a fall. Loose rugs increase the risk of tripping and should be removed or carefully attached to the floor with removable adhesive strips or pads. Seat belts reduce the risk of injury in a car crash and should be worn while driving or riding in a vehicle. A wrap-around rear view mirror can improve visibility for drivers who cannot turn their head and neck.
To avoid developing deformities of the neck, a thin, rather than a thick pillow, is recommended for sleeping.
Nonsteroidal antiinflammatory drugs (NSAID) — An NSAID is commonly used to control pain and stiffness. NSAIDs need to be taken on a regular basis for several weeks before their maximum effect can be judged. (See “Patient information: Nonsteroidal antiinflammatory drugs (NSAIDs)”.)
Sulfasalazine — Sulfasalazine is a disease-modifying antirheumatic drug, or DMARD, that may be given to slow or stop the progression of ankylosing spondylitis. It may be given along with NSAIDs. This drug provides some relief of arthritis symptoms but is not helpful if ankylosing spondylitis only affects the spine. (See “Patient information: Disease modifying antirheumatic drugs (DMARDs)” and “Patient information: Sulfasalazine and the 5-aminosalicylates”.)
Anti-tumor necrosis factor therapy — A group of medicines known as anti-tumor necrosis factor agents (anti-TNF) or TNF inhibitors are often effective in the treatment of ankylosing spondylitis. Examples of anti-TNF medications include: infliximab, etanercept, adalimumab, certolizumab pegol, and golimumab. People who do not respond to one anti-TNF treatment may respond to another. Improvement in symptoms is common and may occur within a few weeks of starting the drugs. However, these drugs may not be very effective in stopping the progression of the disease.
- Who should use anti-TNF therapy? — Not every patient with ankylosing spondylitis needs anti-TNF therapy. In general, people with active disease in the spine who have not responded fully to NSAIDs may be candidates. The decision to use anti-TNF therapy depends upon several factors that should be discussed with your physician.
Some physicians may also recommend a glucocorticoid injection into particularly painful or swollen joints, especially if there is only one or a two that are causing the most pain (see ‘Glucocorticoids (steroids)’ below).
Glucocorticoids (steroids) — In some cases, a glucocorticoid injection into the sacroiliac joint may help provide relief in patients who have sacroiliac pain that has not responded to other therapies.
In contrast, taking glucocorticoids by mouth is rarely necessary in ankylosing spondylitis treatment.
Surgery — Hip or spine surgery may be beneficial in selected patients with ankylosing spondylitis. Surgical procedures may include one or more of the following:
Total hip replacement — Insertion of an artificial hip may be recommended in patients with ankylosing spondylitis who have severe, persistent hip pain or severely limited mobility due to hip joint arthritis. (See “Patient information: Total hip replacement (arthroplasty)”.)
Spinal surgery — Fusion of the bones in the cervical spine may be recommended for a small number of patients who develop dislocation of these bones. Such surgery may help prevent spinal cord damage.
Wedge osteotomy — Wedge osteotomy involves the removal of a wedge-shaped piece of bone from a vertebra, followed by realignment of the spine. The spine is then braced and allowed to heal in a better position. This type of procedure may be recommended for people who develop severe deformities of the neck that prevent them from turning their head in a forward direction.
PREVENTING ANKYLOSING SPONDYLITIS COMPLICATIONS — Because the severity and outcome of ankylosing spondylitis vary considerably among patients, treatment must be tailored to each particular patient. However, all patients can benefit from the following:
- Stop smoking cigarettes. People who smoke and have ankylosing spondylitis can have problems with their breathing. Ankylosing spondylitis can limit the movement of the chest and reduce the amount of air the lungs can hold. (See “Patient information: Quitting smoking”.)
- Maintain correct posture and participate in an exercise program. (See “Patient information: Arthritis and exercise”.)
- Consuming an adequate amount of calcium and vitamin D can reduce the risk of bone loss (osteoporosis). Products that contain calcium and vitamin D include dairy products like milk, cheese, and yogurt or non-prescription calcium and vitamin D supplements. (See “Patient information: Calcium and vitamin D for bone health”.)
Medications that treat bone loss may be recommended if you have already lost bone strength. (See “Patient information: Bone density testing” and “Patient information: Osteoporosis prevention and treatment”.)
UNDIFFERENTIATED SPONDYLOARTHRITIS — Someone who has spondyloarthritis but who does not have sufficient features to be diagnosed as having ankylosing spondylitis, reactive arthritis, arthritis associated with psoriasis, ulcerative colitis, or Crohn’s disease, may be diagnosed as having undifferentiated spondyloarthritis. The major involvement might be the spine or the extremities, or both. The approach by the doctors towards diagnosis and treatment are similar to those of ankylosing spondylitis listed above (See ‘Ankylosing spondylitis treatment’ above.).
If a diagnosis of undifferentiated spondyloarthritis is made, additional medical visits are necessary, because with time, one of the more specific types of spondyloarthritis may be diagnosed. However, some patients continue to have undifferentiated spondyloarthritis and some go into remission and can stop taking medications for pain and stiffness.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed every four months on our web site (www.uptodate.com/patients).
Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information:
Patient information: Disease modifying antirheumatic drugs (DMARDs)
Patient information: Arthritis and exercise
Patient information: Nonsteroidal antiinflammatory drugs (NSAIDs)
Patient information: Sulfasalazine and the 5-aminosalicylates
Patient information: Total hip replacement (arthroplasty)
Patient information: Quitting smoking
Patient information: Calcium and vitamin D for bone health
Patient information: Bone density testing
Patient information: Osteoporosis prevention and treatment
Professional Level Information:
Clinical manifestations of ankylosing spondylitis in adults
Diagnosis and differential diagnosis of ankylosing spondylitis in adults
Diseases of the chest wall
General guidelines for cost-conscious use of anti-tumor necrosis factor alpha agents in ankylosing spondylitis and axial spondyloarthritis
Pathogenesis of spondyloarthritis
Assessment and treatment of ankylosing spondylitis in adults
Clinical manifestations, diagnosis, and management of undifferentiated spondyloarthritis and related spondyloarthritides
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- Rudwaleit M, van der Heijde D, Landewé R, et al. The Assessment of SpondyloArthritis International Society classification criteria for peripheral spondyloarthritis and for spondyloarthritis in general. Ann Rheum Dis 2011; 70:25.
- Sampaio-Barros PD, Bortoluzzo AB, Conde RA, et al. Undifferentiated spondyloarthritis: a longterm followup. J Rheumatol 2010; 37:1195.