Ankylosing Spondylitis (AS)

What Is Ankylosing Spondylitis?

Ankylosing spondylitis (AS) is a type of arthritis that affects your spine. It can cause pain, stiffness, and inflammation from your neck to your lower back. When you have this condition, the vertebrae in your spine can fuse together. This makes your spine less flexible and might lead to a hunched-over posture and trouble breathing. Early diagnosis and treatment can control the condition and prevent these and other problems.

Symptoms of Ankylosing Spondylitis

  • Pain and stiffness. You may have constant pain and stiffness in the low back, buttocks, and hips that continues for more than 3 months. Ankylosing spondylitis often starts around the sacroiliac joints, where the sacrum (the lowest major part of the spine) joins the ilium bone of the pelvis in the lower back region. It might hurt more at night and get better when you wake up. You might also feel pain in other joints such as your knees, shoulders, and jaw.
  • Bony fusion. Ankylosing spondylitis can cause an overgrowth of the bones, which may lead to abnormal joining of bones, called "bony fusion." Fusion affecting bones of the neck, back, or hips may affect your ability to perform everyday things. Fusion of the ribs to the spine or breastbone may limit your ability to expand your chest when taking a deep breath.
  • Pain in ligaments and tendons. Spondylitis also may affect some of the ligaments and tendons that attach to bones. Tendinitis (inflammation of the tendon) may cause pain and stiffness in the area behind or beneath the heel, such as the Achilles tendon.
  • Bent posture. If AS has gone undiagnosed and untreated, you might have a stooped posture from changes to your vertebrae.
  • Breathing problems. Changes in posture can lead to changes in your lungs that make it hard to breathe.
  • Heart trouble. The inflammation can also affect your heart.
  • Eye problems. AS is linked to uveitis, a condition that causes inflammation in your eyes. Symptoms include pain, light sensitivity, and blurry vision.
  • Inflammatory bowel disease. The inflammation can also affect your digestive system. You might notice diarrhea, belly pain and cramps, bloody poop, less appetite, and weight loss without trying.
  • Psoriasis. About 10% of people with AS have this immune system disease that causes scaly, itchy red patches on their skin.
  • Fatigue. You could feel run down because of lack of sleep due to pain or as a part of the disease process itself.
  • Dactylitis. You may get swollen toes or fingers.
  • Fever. You might have a mild fever. 

Over many years, AS can cause new bone to grow on your spine, fusing the vertebrae and making it harder to move. This can cause severe stiffness. About half the people who have AS get osteoporosis, or brittle bones.


Ankylosing Spondylitis Causes and Risk Factors

Several things make AS more likely:

  • Age. It tends to start between your teens and 30s.
  • Gender. Men are two to three times more likely to get the disease than women.
  • Genetics. You can inherit it from your parents. One gene, called HLA-B27, is common in people with AS.
  • Ethnicity. AS appears more often among native tribes in the U.S. and Canada, especially Alaskan Eskimos.

Types of Ankylosing Spondylitis

There are two types of AS.

  • Axial AS causes lower back pain.
  • Peripheral AS causes pain and swelling in joints other than your spine.

Ankylosing Spondylitis Diagnosis and Tests

To get started, your doctor will look for signs of back pain caused by inflammation, such as:

  • Ongoing back pain that started in your 20s or 30s
  • Back pain that’s lasted 3 months or more
  • Pain that’s worse after you rest
  • Pain that gets better when you exercise or move around
  • Pain and stiffness that respond well to anti-inflammatory drugs (like ibuprofen)

Besides asking you about your symptoms, your doctor will do tests. A physical exam can show signs of inflammation in your joints or limited back movement. The doctor will ask you about your medical history and find out if your parents or other relatives had the condition. You may see a specialist called a rheumatologist (an arthritis doctor) to diagnose or treat your AS.

Imaging tests used to diagnose AS include:

  • X-ray. Remember, early on when you have AS, there may be no signs of the disease on an X-ray. It usually shows up after several years.
  • Magnetic resonance imaging (MRI). An image of your sacroiliac joints (where your spine connects to your pelvis) may show swelling and inflammation.
  • CT scan . This is an image that uses X-rays.
  • Blood tests. They look for the HLA-B27 gene or signs of inflammation.

What Are the Treatments?

Many medications are used as ankylosing spondylitis treatments. Newer ones may stop inflammation before it starts to damage your joints or organs like your eyes. Treatments include:

Surgery can help a curved spine or neck as well as damaged knees and hips.


Are There Alternative Treatments for AS?

Ask your doctor about how these techniques can help ease pain and stiffness in addition to your other treatments:

Home Remedies for Ankylosing Spondylitis

Things you can do at home to improve your AS symptoms include:

  • Exercise daily. Moving helps you stay flexible. It can help you ease back pain and stiffness. A physical therapist can teach you how to exercise safely. Work out in a warm pool to make movement easier.
  • Practice posture. Sitting and standing up straight may help with pain and stiffness.
  • Heat and cold therapy. Using moist heat pads or taking hot showers can ease your stiff, sore back. Cold packs can lower swelling in inflamed joints.
  • Healthy lifestyle and food choices. Keep a healthy body weight or ask your doctor how you can lose weight if you need to. Extra pounds stress your back and other joints. Smoking makes AS worse.

Prognosis for Ankylosing Spondylitis

AS shouldn’t affect how long you live. You may have mild back pain that comes and goes. But if your disease is more severe, your spine may curve or stiffen over time and may become fused. Your rib cage could also become fused, making it hard to take a deep breath.

Tips for Living With AS

Follow these steps to feel your best with AS:

  • Follow your treatment plan. Take your drugs as prescribed, don’t smoke, and exercise daily to help ease your inflammation and prevent spine fusion or organ damage.
  • Watch for signs of inflammation in other areas. Talk to your doctor if you have pain or redness in your eyes, pain in your stomach, or a patchy rash on your skin.
  • Get support. It’s helpful to talk to others who have AS. The Spondylitis Association of America has support groups in many areas as well as online communities.
WebMD Medical Reference Reviewed by Tyler Wheeler, MD on April 14, 2019



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