An Overview of Ankylosing Spondylitis

In This Article

Ankylosing spondylitis is a type of arthritis characterized by chronic inflammation which primarily affects the back and neck (i.e., spine).

In severe cases, bones in the spine may fuse (also referred to as ankylosis) resulting in a rigid and inflexible spine. Abnormal posture may be a consequence. Other joints may also be involved, including the hips, knees, ankles, or shoulders. The disease may also be associated with systemic effects affecting various organs of the body.

1:55

What Is Ankylosing Spondylitis?

Classification

Ankylosing spondylitis belongs to a group of conditions known as spondyloarthropathies. Other spondyloarthropathies include:

Spondyloarthropathies are classified as axial or peripheral, depending on which joints are involved. Axial refers to the involvement of the spine. Peripheral refers to other joints outside of the spine.

Ankylosing spondylitis is an axial spondyloarthropathy.

Who Gets Ankylosing Spondylitis?

The condition primarily affects men. Two to three times more men than women develop the disease. However, anyone can develop ankylosing spondylitis. The age of disease onset is usually between 17 to 35 years old.

According to the CDC (Centers for Disease Control and Prevention's NHANES study), at least 2.7 million adults in the United States have axial spondyloarthritis.

Causes

The cause of the condition is unknown, but the genetic marker, HLA-B27, is present in 90 percent of people with the disease, suggesting a genetic connection. However, it's important to note that not everyone who has the HLA-B27 marker develops ankylosing spondylitis.

According to the Spondylitis Association of America, there are over sixty other genes/genetic markers involved in susceptibility to ankylosing spondylitis. Researchers believe that a triggering environmental event combined with susceptibility is what causes the disease to develop.

Symptoms

The earliest symptoms of ankylosing spondylitis are typically pain and stiffness in the lower back region. Symptoms usually start before the age of 45. The pain and stiffness evolve and develop into chronic symptoms. Typically, ankylosing spondylitis pain worsens following rest or inactivity and improves with activity. It can cause morning stiffness that lasts more than 30 minutes.

Pain and stiffness, over time, can progress up the spine to the neck. The bones of the spine and neck may fuse, causing limited range of motion and decreased flexibility of the spine. As already mentioned, shoulders, hips, and other joints may be involved.

Hip pain is quite common with ankylosing spondylitis and may be associated with pain in the groin or buttocks, as well as difficulty walking. If the rib cage is involved, abnormal chest expansion may cause breathing difficulties. Tendons and ligaments may be affected (e.g., heel involvement with Achilles tendonitis and plantar fasciitis).

Ankylosing spondylitis is a systemic disease as well, meaning that people may develop fever, fatigue, eye, or bowel inflammation. Heart or lung involvement is rare but possible.

Diagnosis

The diagnosis is essentially based on symptoms, a physical examination, blood tests, and imaging studies. Early symptoms of ankylosing spondylitis can mimic other conditions, so diagnostic tests are used to rule out other rheumatic diseases. The absence of rheumatoid factor and rheumatoid nodules help to distinguish it from rheumatoid arthritis.

While there is no single blood test that can definitively diagnose ankylosing spondylitis, the HLA-B27 test provides an important diagnostic clue, especially in certain groups of people.

For example, ankylosing spondylitis is an unlikely diagnosis in someone who is white, of European descent, and negative for HLA-B27. Tests for nonspecific inflammation (sedimentation rate and CRP) are useful for formulating the clinical picture, but they are not diagnostic.

Imaging studies often show characteristic changes in the bones of the sacroiliac joints. While the changes can be seen on X-rays, it may take years after the onset of symptoms to be observable. MRI can also be utilized to look for the characteristic changes to the sacroiliac joints, often detecting them earlier than X-ray images. X-rays are used to assess evidence of damage to the spine as well.

Treatment

Treatments for the condition primarily focus on reducing pain, stiffness, and inflammation. Preventing deformity, maintaining function, and posture are also goals of treatment.

Medications used to treat ankylosing spondylitis include the following:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) are the first line of pharmacologic treatment. Many people use NSAID medication alone to manage it.
  • Analgesics or pain medications may be used when pain is not well-controlled by NSAIDs alone.
  • TNF-blockers (Humira (adalimumab), Remicade (infliximab), Enbrel (etanercept), Cimzia (certolizumab pegol), and Simponi (golimumab)) are approved to treat ankylosing spondylitis and have shown significant improvements in disease activity.
  • Cosentyx (secukinumab), an IL-17 inhibitor, was approved in January 2016 for the condition.
  • DMARDs (disease-modifying antirheumatic drugs) may be used to slow disease progression. Typically, sulfasalazine is used in ankylosing spondylitis patients with peripheral arthritis who cannot use a TNF blocker. Methotrexate alone may help some people, but generally it is not considered effective for ankylosing spondylitis. Another DMARD, Arava (leflunomide), is regarded as having little or no benefit.
  • Oral corticosteroids are rarely used, but when they are taken, it should be short term, not long term.

    Physical therapy and exercise are a significant part of any treatment plan for ankylosing spondylitis. The importance of exercise, as part of managing the disease and preserving mobility and function, cannot be overstated.

    Prognosis

    Some people with the condition have a mild disease course and are able to work and function normally. Others develop severe disease and live with considerable restrictions due to the axial disease. Some people with ankylosing spondylitis develop life-threatening extra-articular complications—but that is not the case for most.

    Typically, an individual patient deals with fluctuating disease activity that, for the most part, is manageable. A minority of people with the disease actually achieve a stage where symptoms diminish and they are considered in remission.

    If you have questions or concerns, talk with your healthcare professional. The treatment, coping, and living well strategies they offer can improve how you feel and your overall outcome.

    Ankylosing Spondylitis Doctor Discussion Guide

    Get our printable guide for your next doctor's appointment to help you ask the right questions.

    Doctor Discussion Guide Man

    Living Well

    A spine that has fused, or that is less flexible, is more susceptible to fracture. That said, you must be mindful of the extra risk and take precautions. You should talk to your healthcare professional about limiting or avoiding behaviors that may increase your risk of falling. This can include anything from limiting the amount of alcohol you consume to installing grab bars and picking up throw rugs in your house. Avoid high-impact activity. Basically, use common sense and be protective of your spine.

    Consider using a pillow that places your neck and back in good alignment while you rest or sleep. Always use your seat belt when driving or as a passenger in a vehicle. Also, people with ankylosing spondylitis who smoke are advised to quit in order to lower their risk of breathing problems. And don't forget the importance of participating in an exercise program to strengthen your spine and improve your overall joint health.

    A Word From Verywell

    If the symptoms that ankylosing spondylitis causes are impacting your daily life, know that treatment options are available. Talk to your healthcare team about what medications or therapy programs are right for you. Outside of medications, many people find that simple stretches and physical therapy go a long way in helping their body feel better. Start slow and explore moves that are right for you. It may take some time, but you may discover something helpful.

    Was this page helpful?

    Article Sources

    • Spondyloarthritis. Cleveland Clinic. 11/04/2014.
    • Ankylosing Spondylitis. Spondylitis Association of America.

    • Van der Linden S et al. Ankylosing Spondylitis. Kelley's Textbook of Rheumatology. Chapter 75. Elsevier. Ninth edition.