In truth, nearly all the symptoms of ankylosing spondylitis, a type of arthritis that primarily affects the spine, can be tricky to identify—even by medical professionals. It's not unusual for patients to go months or even years before receiving an accurate diagnosis.

However, these 5 are particularly unusual, and they can create a challenge for both those with ankylosing spondylitis and the doctors who treat them.

See how the process of ankylosing spondylitis affecting the SI joints and spine usually begins. Watch: Ankylosing Spondylitis Video

Most often, ankylosing spondylitis first appears in the sacroiliac joints between the spine and pelvis, causing pain in the buttocks, hips, and lower back. But it can show up in other joints too—mainly the neck, arms, or legs.

See Ankylosing Spondylitis Symptoms

Because ankylosing spondylitis is a system-wide autoimmune disorder, it can also affect organs like the lungs, heart, or eyes. This seeming lack of connection between symptoms is one of the primary reasons it can be so difficult to diagnose.

Ankylosing Spondylitis Diagnosis


This guide tackles 5 of the more unexpected symptoms of ankylosing spondylitis. You can also read our expanded article on these symptoms.

  1. Inflammation of the iris (known as iritis)

    Up to 40% of those with ankylosing spondylitis will experience inflammation of the eye's iris at some point. It can come on quickly (acute iritis) or gradually (chronic iritis). Symptoms include:

    • Pain in or around the eye
    • Blurred vision
    • Sensitivity to light
    • Pupil redness or difference in size
  2. Chest pain

    Ankylosing spondylitis causes joints to become inflamed and,eventually, fuse together. When this occurs in the rib joints, the ribs can become inflexible and constrict the lungs, causing severe chest pain.

    Since heart problems can also accompany ankylosing spondylitis, it's important to see your doctor if you are experiencing chest pain.

  3. Lesions in the heart

    In some cases of ankylosing spondylitis, inflammation at the site where the aorta meets the heart can cause heart lesions. This is an extremely rare symptom that only affects 2% of people with ankylosing spondylitis.

  4. Cauda equina syndrome

    The cauda equina is a bundle of nerves that exit the bottom of the spine. When inflammation causes this bundle to be compressed, cauda equina syndrome is the result.

    See Complications of Severe Ankylosing Spondylitis

    Symptoms of the syndrome include incontinence, numbness in the legs, trouble balancing, and trouble speaking. Cauda equina syndrome is a medical emergency, so anyone experiencing these symptoms should get medical help immediately.

  5. AA amyloidosis

    AA amyloidosis occurs when amyloid, a bone marrow protein, builds up in organs of the body—mainly the kidneys but also the heart, liver, or digestive tract. Like ankylosing spondylitis, the symptoms of AA amyloidosis can be hard to pin down. They can include numbness in the hands and feet, swelling in the legs or ankles, feeling full easily, or weight loss.

If you have been diagnosed with ankylosing spondylitis and you experience new symptoms or your symptoms get worse, make an appointment with your doctor. In many cases, there are medications or other treatment options to help manage your symptoms.

See Ankylosing Spondylitis Treatment

Learn more:

Ankylosing Spondylitis Physical Therapy and Exercise

Interview: Helgi Olafson, Triathlete with Ankylosing Spondylitis

Stephanie Burke is the CEO, Co-Founder, and Editor-in-Chief of Veritas Health. She and her brother, Dr. Peter F. Ullrich, started Spine-health in 1999 with the vision of providing people with high-quality health information online.