Ankylosing Spondylitis

What Is Ankylosing Spondylitis?

Ankylosing spondylitis is a form of arthritis that primarily affects the spine. Spondylitis is an inflammation of the vertebrae, which are the building blocks of the spine.

  • Spondylos is the Greek word for vertebra
  • Ankylosing, from another Greek word, agkylosis, means causing stiffness and immobility of a joint

Inflammation is the body’s response to a variety of causes of irritation or injury. In this disease, the inflammation causes:

  • Swelling
  • Stiffness in the joint between the pelvic bones (the ilium) and the wedge-shaped bone at the base of the spine (the sacrum)
  • Pain
  • Difficulty moving

Ankylosing spondylitis also can cause inflammation of the eyes, lungs, and heart valves.

Here is how ankylosing spondylitis progresses in the body:

  • Ankylosing spondylitis causes inflammation of the ligaments and tendons where they connect the vertebrae.
  • This inflammation causes some damage to the bone, and the body heals this damage by growing new bone.
  • This bony growth replaces the elastic soft tissue and can fuse the joints of the vertebrae.
  • This fusion causes further stiffness and pain.
  • Stiffness and pain usually begins in the pelvis and near the base of the spine and progresses upward through the back to the neck.
  • It can also affect the hips and shoulders, the other larger joints of the arms and legs, and the heels.

Ankylosing spondylitis is a relatively uncommon disease that usually strikes in the late teens and early adulthood. It can be mild or somewhat severe. Early diagnosis and treatment can control the pain and stiffness and reduce the possibility of major disability.

Nice To Know:

Ankylosing spondylitis is one of a group of arthritic diseases called “spondyloarthropathies.” These diseases, which tend to cause chronic inflammation of the spine, include:

  • Reactive arthritis, formerly called Reiter’s syndrome, an arthritic disorder that often affects several joints in the legs such as knees, the feet, ankles, and sacroiliac joint following a triggering intestinal or genital infection.
  • Psoriatic arthritis a form of arthritis associated with scaly skin lesions (psoriasis), especially on the fingers and toes.
  • Arthritis associated with inflammatory bowel disease (Crohn’s disease).
  • Arthritis associated with ulcerative colitis.

For further information about Crohn’s disease, see Crohn’s Disease.

For further information about ulcerative colitis, see Ulcerative Colitis.

Understanding The Spine

The spine is made up of 33 bones called vertebrae and 110 joints. It is divided into:

  • Seven cervical vertebrae (neck)
  • 12 thoracic vertebrae (the upper back with the attached ribs)
  • Five lumbar vertebrae (the lower back)
  • Five sacral vertebrae (that fuse to form the sacrum)
  • Four coccygeal vertebrae (the tailbone)

The neck is the most mobile area of the spine. The flat, triangular sacrum is joined to the pelvis by two sacroiliac joints. The ilium is the broad, wing-like plate of the pelvis.

Each of the joints is held together by tendons and ligaments and separated by intervertebral disks.

Facts about ankylosing spondylitis

  • A tendency to develop ankylosing spondylitis runs in families; it is 10 to 20 times more common in people whose parents or siblings have it.
  • It is most prevalent among Native Americans, some Asians (but not Japanese), and white Europeans.
  • Ankylosing spondylitis is a relatively uncommon disease. According to the American College of Rheumatology, 129 out of 100,000 people in the United States have ankylosing spondylitis.
  • As many as two million Americans are living with ankylosing spondylitis.
  • Ankylosing spondylitis occurs in men three or four times more often than in women.
  • It most often begins between the ages of 20 and 40, but in some cases it may begin before age 10.


What Causes Ankylosing Spondylitis?

The specific cause of ankylosing spondylitis is unknown, but genetic factors seem to play a role.

  • About 95% of people who have ankylosing spondylitis also have a genetic marker known as human leukocyte antigen-B27 (HLA-B27).
  • About eight people in 100 among American Caucasians are born with the HLA-B27 gene. The gene is much less common among African Americans.

Genetic markers are protein molecules found on the surfaces of cells. The HLA markers enable the body’s immune system to distinguish between “self” and “other.”

Ankylosing spondylitis may be triggered by certain types of bacterial or viral infections that activate an immune response that does not shut off after the infection is healed. The immune system then attacks the body’s own tissue. A disorder caused by the body’s own immune system is called an autoimmune disease.

Is Ankylosing Spondylitis Inherited?

If one parent has HLA-B27 and ankylosing spondylitis, there clearly is some increased risk that the B27 gene and disease will be passed on to a child. However, only about 2% of people with HLA-B27 develop ankylosing spondylitis.

Ankylosing spondylitis occurs more frequently in some ethnic groups. In the United States, it occurs most frequently among Native Americans and is almost never found among African Americans. Chinese individuals have the gene much more often than Japanese individuals.

Is Ankylosing Spondylitis Different In Men And Women?

Men develop ankylosing spondylitis about three times more often than women do. The disorder affects men and women differently.

  • Men are more likely to have the inflammation of the spine, pelvis, chest wall, and shoulders
  • Women are more likely to have inflammation of the pelvis, hips, knees, and wrists.

A diagnosis of ankylosing spondylitis may sometimes be missed in women because the disease affects them somewhat differently and has been considered less severe.

Do Children Get Ankylosing Spondylitis?

It is rare, but possible, for ankylosing spondylitis to develop in childhood. It usually does not strike until adolescence, and it is unusual for a child under 11 years old to develop the disease.

When symptoms begin before the age of 17, the condition is called juvenile ankylosing spondylitis. According to the Spondylitis Association of America, one child in a thousand may develop juvenile ankylosing spondylitis.

What Are The Symptoms Of Ankylosing Spondylitis?

Early symptoms of ankylosing spondylitis usually begin in early adulthood. They begin gradually and include:

  • Gradual onset of back pain before the age of 35
  • The pain usually begins low and slowly progresses up the spine
  • Early morning stiffness and pain that subsides with movement and heat
  • Pain relieved by movement and not by rest
  • Symptoms last more than three months
  • Fatigue
  • Weight loss, in the early stages

Does Ankylosing Spondylitis Affect Only The Back?

Ankylosing spondylitis is a disease that can cause inflammation of muscles and joints and other tissues throughout the body.

  • About 25% of people with ankylosing spondylitis develop pain in other joints.
  • Men frequently have pain in the hips, shoulders, and feet.
  • Women are sometimes affected in the knees, wrists, and ankles.
  • Sometimes the disease begins as pain radiating from the buttocks to the back of the leg.
  • The heel can be affected at the bottom of the foot as plantar fasciitis or along the back as Achilles tendinitis or where it inserts into the heel (enthesitis).
  • Ankylosing spondylitis sometimes affects the eyes, causing redness, pain, and sensitivity to bright light. This inflammation affects the colored part of the eye (the iris) and the surrounding membrane (the uvea). Inflammation of the eye must be treated immediately to prevent scarring, cataract formation, and bleeding.
  • Ankylosing spondylitis sometimes causes a long-term mild inflammation of the base of the aorta (the main artery of the heart) and the adjacent heart muscle. Although this condition is usually mild, if it goes undetected it can interfere with the electrical impulses that control the action of the muscle. It may also cause the aortic valve to leak.
  • Ankylosing spondylitis can affect the rib joints and make it difficult to inflate the lungs completely. After some time, this condition may decrease the capacity of the lungs. Some people develop scarring (fibrosis) at the top of the lungs.

Will I Become Disabled?

In its severe forms, ankylosing spondylitis can cause complete fusion of the spine (ankylosis). This fusion can cause a forward curvature of the upper torso (kyphosis) and can keep the ribs from expanding, which can make breathing difficult.

However, many people experience a mild form of the disease and are able to live a completely normal life. Others have to make some modifications to their lifestyle and work. Most people with ankylosing spondylitis are able to work full time.

Ankylosing Spondylitis: How Is The Diagnosis Made?

Early symptoms of ankylosing spondylitis are very like those of many other conditions that cause pain in the lower back. In teenagers, it is often mistaken for a sports injury. It may be years before a diagnosis of ankylosing spondylitis is considered.

  • The first step in the diagnosis of ankylosing spondylitis is to take a thorough history of symptoms and make a physical examination. The doctor may check for tenderness over the sacroiliac joint. The doctor may check range of motion in the lower back and in the entire spine, and may also measure the ability to expand the chest.
  • An x-ray of the pelvis can show inflammation or fusion of the sacroiliac joint and bony overgrowth or fusion of the spine.
  • Magnetic resonance imaging (MRI) or computed tomography (CT) scan of the back may show early effects of the disease on the sacroiliac joint and vertebrae.
  • Blood tests may be done to look for evidence of inflammation. Low-grade anemia (a lack of enough red blood cells or hemoglobin, which is the protein that carries oxygen in the blood) is also an indicator of chronic disease.
  • Tests are sometimes done to check for HLA-B27 when the diagnosis is in doubt. Generally, however, presence of HLA-B27 is useless as a diagnostic indicator, as many people with back pain of other causes may also have this gene.

For further information about MRI, see MRI.

For further information about CT Scan, see CT Scan.

Treatment of Ankylosing Spondylitis

Ankylosing spondylitis cannot be cured, but it can be effectively managed with:

In addition to your rheumatologist, you may need to see other specialists if you develop related problems:

  • Inflammation of the eyes should be treated by an ophthalmologist
  • Inflammation of the heart should be treated by a cardiologist

Need To Know:

Surgery is not a usual treatment for ankylosing spondylitis. However, if the disease becomes severe, hip replacement or shoulder replacement may become necessary. Surgery can also rarely be done in a specialized center to straighten the spine.

For further information about hip replacement, seeTotal Hip Replacement.


Non-steroidal anti-inflammatory drugs (NSAIDs) are most often prescribed for ankylosing spondylitis. These include:

  • Aspirin (however, aspirin should never be given to children)
  • Indomethacin (most people begin with 150 to 200 mg per day)
  • Ibuprofen (Motrin, Advil)
  • Naproxen (Aleve)

No particular NSAID is proven superior for treating this condition. Each person should use the one he or she finds most effective. NSAIDS can cause an upset stomach or ulcers and should always be taken with food and a full glass of water.

  • An antacid or a histamine blocker such as cimetidine may be prescribed to help with stomach upset, but these do not protect against possible damage to the stomach that can be caused by the anti-inflammatory drugs.
  • Proton pump inhibitors such as omeprazole and misoprozal provide more protection.

If NSAIDs are not effective, stronger drugs may be prescribed. These include:

  • Sulfasalazine, an anti-inflammatory drug (most effective when joints other than the spine are involved)
  • Methotrexate, an anti-inflammatory that also suppresses the body’s immune system (most effective when joints other than the spine are involved)
  • TNF antagonists, etanercept and remicade, are potent new injectable agents that appear to be dramatically effective in early studies and may be an important advance.
  • Corticosteroids (cortisone) may be injected into a joint to relieve inflammation

Oral corticosteroids are usually not prescribed for long periods of time, as they can cause severe osteoporosis (a condition in which bones become thin and weakened) and an increased risk of bone fracture. These drugs also have serious side effects and must be monitored carefully.

Nice To Know:

Use of new specific COX2 inhibitors (rofecoxib or celecoxib) can be considered, although they have not been studied for treatment of ankylosing spondylitis.

Physical Therapy

Physical therapy involves specially designed and monitored exercises. The goal is to help keep the joints flexible and to maintain range of motion.

  • Back extension exercises work against the tendency for the spine to curve forward.
  • Deep breathing exercises help expand and maintain the capacity of the lungs.
  • Therapists also teach proper sleeping and sitting postures.


Exercise can be extremely helpful to people with ankylosing spondylitis. A regular exercise program is very important for maintaining strength of muscles and flexibility of joints.

The following exercises are recommended by the National Ankylosing Spondylitis Society in England. Do them once or twice a day, and try to make them part of your normal daily routine. Repeat each of them at least five times.

Floor exercises:

  1. Lie on your back with both knees bent and your feet flat on the floor. Lift your hips off the floor as high as possible, hold for five seconds, and lower slowly.
  2. Then lift your arms towards the ceiling, with fingers linked together.
  3. Keeping your chin tucked in toward your chest, reach both hands toward your knees, lifting your head and shoulders off the floor. Relax.
  4. Keeping your chin tucked in, lift your head and shoulders off the floor, and reach both hands towards the outside of your right knee. Repeat to the opposite side.
  5. Kneel on all fours. Keeping your elbows straight throughout, tuck your head between your arms and arch your back as high as possible. Then lift your head and round your back the other way as much as possible.
  6. Keeping your head up, raise your right arm forward as you raise your left leg backward. Hold for five seconds. Return to all fours and change to raising your left arm and right leg.

Chair exercises:

  1. Sit on a stable chair with your feet on the floor, hooked around the legs of the chair. Place your hands by your sides. Hold the chair with your left hand. Bend sideways toward the right as far as possible, without bending forwards, reaching your right hand toward the floor. Repeat to the opposite side.
  2. With your hands clasped on your forearms at shoulder level, turn your upper body to the right as far as possible. Repeat to the opposite side.
  3. Hold the sides of the chair site. Turn your head to the right as far as possible without letting your shoulders turn. Repeat to the opposite side.
  4. Stand facing the chair (for comfort, use one with a padded seat). Place your right heel on the seat, keeping the knee straight, and reach forward as far as possible with both hands toward your foot. Hold for six seconds. Relax. Repeat twice, stretching a little further each time. Repeat with the opposite leg.
  5. Face the side of the chair and hold the chair back with your right hand. Bend your right knee and place your right shin on the seat. Place your left foot forward as far as possible. Now place both hands behind your back. Bend your left knee as much as possible, keeping your head up and your back straight. Turn around to face the other side of the chair and repeat with the opposite leg.

Posture exercises:

  1. Stand with your back to the wall, shoulders and buttocks against the wall and heels as close to the wall as you can. Tuck your chin in and push the back of your head toward the wall. Keep your shoulders down.
  2. Stretch up as tall as possible without lifting your heels. Hold this position. Raise your right arm forward and upward while keeping your elbow straight, your upper arm close to your ear, and your thumb towards the wall. Lower and repeat with the opposite arm.

Need To Know:

Swimming is particularly recommended because it does not jar the spine. The buoyancy of the water also makes it easier to move all of the affected joints and muscles.


Living With Ankylosing Spondylitis

Ankylosing spondylitis affects different people in different ways.

  • The pain and stiffness will come and go. It will sometimes disappear completely for a while.
  • In the most severe cases, the entire spine can become stiff and bent, so that the person cannot look at the horizon. This condition is called kyphosis.
  • People with mild disease will never develop this stoop, but it is hard to make early predictions about the severity of the disease in each person.

How To Information:

Careful attention to posture and exercise, however, works against the tendency to stoop. Here are some steps you can take:

  • Sleep on a mattress that is firm but not hard. Use a thin pillow so that the neck is not bent forward. Sleep on the back or the stomach with the spine straight.
  • Sit in a chair that has a firm seat and an upright firm back. The depth of the seat and the height of the chair should allow sitting with the knees and the hips at right angles.
  • Do not sit or lie still for long periods. Stretch your back. Sit tall. Get up and walk around.
  • Avoid corsets and back supports. Anything that supports the back will allow the muscles to become weak, and the back will then become more prone to pain and stiffness.
  • A hot bath or shower in the morning may help reduce pain and stiffness. An ice pack or bag of frozen peas wrapped in a towel can be applied to particularly inflamed areas to reduce pain and swelling.
  • Don’t smoke cigarettes. Ankylosing spondylitis can reduce the capacity of the lungs, and smoking can increase the risk of infection and scarring.
  • Keep your weight under control.Remember that when you run or jump, every pound of weight translates into four to eight pounds of pressure on the joints.
  • An active sex life is possible with ankylosing spondylitis. Open communication between partners is essential in overcoming any difficulties caused by pain or limited mobility. Changes in position may be necessary, and planning may help to avoid fatigue.
  • A small cushion behind the back or under the buttocks can help maintain good posture when driving a car. Special wide-angle mirrors are available for those who have limited mobility in the neck. If the drive is extended, make frequent rest stops to move around and limber up.
  • Develop a support network. People who develop a lifelong illness, such as ankylosing spondylitis, may have periods of sadness or anger. It is important to enlist the support of family and friends. A counselor may sometimes be needed to help solve the problems that arise in coping with the disease. It may also help to get to know other people who are coping with ankylosing spondylitis.

Need To Know:

Q: Will I physically be able to maintain a pregnancy if I have ankylosing spondylitis?

A: Unless the condition is very severe, pregnancy is not usually a problem for women with ankylosing spondylitis. However, pregnant women should not take anti-inflammatory drugs.

The Outlook

Most people with ankylosing spondylitis can look forward to productive lives with just a few adjustments for coping with the disease. In fact, living an active life is one of the best ways to treat ankylosing spondylitis.

With exercise and activity, as well as proper medical management, symptoms can be relieved and controlled, and normal life activities can be continued.

Frequently Asked Questions: Ankylosing Spondylitis

Q: Is spondylitis the same as spondylosis?

A: No. Spondylosis is a condition usually caused by degeneration of the discs between the vertebrae. It may be caused by aging or injury and not by an inflammatory disease as in ankylosing spondylitis.

Q: Is rheumatism the same thing as arthritis?

A: No. Rheumatism is a nontechnical term for pain in and around a joint. Arthritis is an inflammation of the joint. Thus everybody with arthritis has a form of rheumatism but not everyone with rheumatism has arthritis.

Q: What kind of doctor treats ankylosing spondylitis?

A: Ankylosing spondylitis is best treated by a rheumatologist, that is, a specialist in treating arthritis.

Q: How does one find a rheumatologist?

A: The primary care physician can make a referral to a rheumatologist. The American College of Rheumatology can also provide a list of rheumatologists practicing in a given area.

Q: I have ankylosing spondylitis, and my wife and I want to have a baby. Should we consider genetic counseling?

A: Genetic counseling can be useful. Some researchers believe that ankylosing spondylitis skips a generation, but this has not been confirmed. However, you may wish to discuss with a genetic counselor the chances of your children having ankylosing spondylitis later in life. Three in ten close relatives of people with the condition will develop it too.

Q: Will I physically be able to maintain a pregnancy if I have ankylosing spondylitis?

A: Unless the condition is very severe, pregnancy is not usually a problem for women with ankylosing spondylitis. However, pregnant women should not take anti-inflammatory drugs.

Q: Is there a cure for ankylosing spondylitis?

A: Ankylosing spondylitis cannot be cured. Anti-inflammatory drugs and exercise are used to manage the condition.

Q: Why is posture so important for people with ankylosing spondylitis?

A: Because ankylosing spondylitis tends to cause stooping associated with fusion of the spinal vertebrae, it is very important to maintain a straight and upright posture even during sleep. Patients may not be able to prevent stiffness, but one can assure that any stiffness is in a functional, less stooped position.

Putting It All Together: Ankylosing Spondylitis

  • Ankylosing spondylitis is type of rheumatism that causes arthritis, predominantly of the spine and pelvis. It can cause inflammation of the eyes, heart valves, and lungs.
  • The major symptoms of ankylosing spondylitis are pain and stiffness.
  • Ankylosing spondylitis cannot be cured, but it can be managed with medication, physical therapy, and exercise.
  • Most people don’t develop disabilities and can lead normal, productive lives.

Glossary: Ankylosing Spondylitis

Ankylosis: Fixation of a joint, often in an abnormal position, such as occurs in rheumatoid arthritis (from the Greek word agkylosis meaning bent condition)

Arthritis: Inflammation of joint (from the Greek word arthron meaning joint and itis, a suffix meaning inflammation of an organ or structure)

Enthesitis: Inflammation where tendons insert into bone

Ilium: The large, wing-like bones of the pelvis

Kyphosis: An exaggerated, forward curve of the thoracic spine. (From the Greek work kyphos meaning hunchbacked)

Ligaments: The slightly elastic bands of tissue that bind the joints together and connect various bones and cartilage

Plantar fasciitis: Inflammation of the connective tissue on the bottom of the foot.

Psoriatic arthritis: A form of arthritis associated with scaly skin lesions (psoriasis), especially on the fingers and toes

Reactive arthritis (formerly called Reiter’s syndrome): An arthritic disorder that often affects several joints in the legs such as knees, the feet, ankles, and sacroiliac joint following a triggering intestinal or genital infection

Rheumatism: Pain and limitation of movement of the musculoskeletal system such as may occur in gout, rheumatoid arthritis, ankylosing spondylitis, and many other diseases (from the Greek wordrheumatismos meaning that which flows)

Sacroiliac joints: The joints that connect the sacrum (the wedge-shaped bone at the bottom of the spine) to the pelvic bones

Sacrum: The wedge-shaped bone between the two wing-like pelvic bones

Tendinitis: An inflammation of a tendon, the tissue that attaches muscle to bone

Tendons: The fibrous bands of tissue that attach muscle to bone

Additional Sources Of Information: Ankylosing Spondylitis

Spondylitis Association of America (SAA) 
Phone: (818) 981-9826
Phone: (800) 777-8189
Fax: (818) 981-9826

American College of Rheumatology 
Phone: (404) 633-3777
Fax: (404) 633-1870

Arthritis Foundation 
Phone: (404) 872-7100
Phone: (800) 283-7800

National Institute of Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse National Institutes of Health 
Phone: (301) 495-4484
Phone: (877) 22-NIAMS
Fax: (301) 718-6366

An 11-page booklet, entitled “A Positive Response to Ankylosing Spondylitis: Answers and Practical Advice,” published by the National Ankylosing Spondylitis Society of the United Kingdom, is downloadable in either Microsoft Word or Adobe format. It has detailed information about ankylosing spondylitis with diagrams of helpful exercises. The statistics are British. Available at

Two websites provided by the United States Department of Health and Human Services provide helpful links to other websites that contain reliable information about ankylosing spondylitis. They are:

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