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Ankylosing Spondylitis

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What is Ankylosing Spondylitis?

Ankylosing spondylitis (AS) is a type of chronic inflammatory arthritis primarily affecting the spine, though it can also impact other joints. It is part of a group of diseases known as spondyloarthritis. AS leads to inflammation of the spinal joints (vertebrae), which can cause pain and stiffness. Over time, this inflammation may lead to the fusion of the vertebrae, resulting in reduced flexibility in the spine. The condition can also affect other areas such as the hips, shoulders, and joints in the pelvis.
 
AS is a long-term condition that progresses slowly, and its severity can vary from person to person.

Causes of Ankylosing Spondylitis

The exact cause of ankylosing spondylitis is not fully understood, but it is believed to be a combination of genetic and environmental factors. The key factors include:

  • Genetics: The vast majority of people with AS carry a gene called HLA-B27. However, not everyone with this gene develops AS, indicating that other genetic factors may also be involved.
  • Immune System Dysfunction: AS is thought to be an autoimmune disease, where the body's immune system mistakenly attacks the joints and tissues in the spine. This leads to inflammation and, over time, damage to the affected areas.
  • Environmental Factors: Certain infections or bacteria may trigger the development of AS in people who are genetically predisposed.

Risk Factors for Ankylosing Spondylitis

Several factors may increase the risk of developing ankylosing spondylitis, including:
 
  • Age: AS typically develops in late adolescence or early adulthood, with most people diagnosed between the ages of 17 and 35.
  • Gender: AS is more common in men than in women, although women can also be affected, and their symptoms may be less severe.
  • Family History: Having a family member with AS or other forms of spondyloarthritis increases your risk.
  • Ethnicity: AS is more common in people of European descent, particularly those of Northern European or Mediterranean ancestry.
  • HLA-B27 Gene: Having the HLA-B27 gene significantly increases the risk, although many people with this gene will never develop AS.

Symptoms of Ankylosing Spondylitis

The symptoms of ankylosing spondylitis can vary widely but commonly include:
 
  • Chronic Back Pain: Pain and stiffness in the lower back and hips are the hallmark of AS. This pain often starts gradually and worsens with prolonged rest, such as after sleeping or sitting for a long time.
  • Morning Stiffness: People with AS often experience stiffness in the back, especially in the mornings, which improves with activity but may return after resting.
  • Reduced Flexibility: Over time, the spine can become less flexible, leading to difficulty bending or moving the back.
  • Pain in Other Joints: While the spine is most affected, AS can also cause pain in the hips, shoulders, knees, and sometimes even in the jaw or ribs.
  • Fatigue: Chronic inflammation and the body's response to it can lead to a feeling of tiredness and low energy.
  • Enthesitis: Inflammation where tendons and ligaments attach to bone, leading to pain in areas such as the heels, elbows, and hips.
  • Other Symptoms: Some people with AS may experience eye inflammation (uveitis), causing pain, redness, and sensitivity to light.

How is Ankylosing Spondylitis Diagnosed?

Diagnosing ankylosing spondylitis can be challenging, as its symptoms can resemble other conditions, and early symptoms may be subtle. The diagnosis typically involves:
 
  1. Medical History: Your doctor will ask about your symptoms, family history, and any history of joint pain or stiffness.
  2. Physical Exam: A thorough exam will assess your flexibility, posture, and the range of motion in your joints.
  3. Blood Tests: Blood tests may show elevated levels of inflammation (such as C-reactive protein or ESR) and can help rule out other conditions.
  4. X-rays: X-ray imaging can detect changes in the spine and pelvis, such as joint damage or the formation of new bone, which are characteristic of AS.
  5. MRI: An MRI may be used to detect early signs of inflammation, even before visible damage is seen on X-rays.
  6. HLA-B27 Test: Testing for the HLA-B27 gene can be helpful, although having the gene alone does not confirm AS, and many people with AS do not carry this gene.

Treatment for Ankylosing Spondylitis

There is no cure for ankylosing spondylitis, but there are several treatments available to manage the symptoms and slow the progression of the disease. Treatment typically includes:
 
Non-Surgical Treatments:
 
  1. Medications:
    • Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): Over-the-counter medications like ibuprofen or naproxen can help reduce pain and inflammation.
    • Disease-Modifying Antirheumatic Drugs (DMARDs): These medications, such as sulfasalazine and methotrexate, can help slow the progression of the disease and reduce joint damage.
    • Biologic Drugs: TNF inhibitors (e.g., adalimumab, etanercept) or IL-17 inhibitors (e.g., secukinumab) are newer biologic treatments that target specific components of the immune system to reduce inflammation and improve symptoms. They are often used when NSAIDs or DMARDs are ineffective.
    • Corticosteroid Injections: Injections of corticosteroids can be used to reduce inflammation in specific joints affected by AS.
  2. Physical Therapy: Regular exercises and stretches are essential in maintaining flexibility and improving posture. A physical therapist can design an exercise program tailored to your needs to strengthen muscles and keep your spine as mobile as possible.
  3. Lifestyle Modifications:
    • Posture Training: Maintaining good posture and avoiding slouching can help reduce pain and prevent further spine damage.
    • Exercise: Low-impact exercises, such as swimming, walking, or cycling, are beneficial in improving flexibility and strength without putting too much stress on the joints.
    • Pain Management: Over-the-counter pain medications, heat or cold packs, and relaxation techniques may help manage discomfort
 
Surgical Treatments:
 
Surgery is typically only considered in severe cases of AS where joint damage or spinal deformities significantly impact function. Surgical options may include:
 
  1. Joint Replacement: In cases of joint damage, particularly in the hips or knees, joint replacement surgery may be recommended.
  2. Spinal Surgery: In severe cases where the spine becomes rigid or deformities occur, surgical procedures may be needed to correct posture or fuse certain areas of the spine to relieve pain and improve function.

Prevention of Ankylosing Spondylitis

Since the exact cause of ankylosing spondylitis is not fully understood, there is no known way to prevent the disease. However, early diagnosis and treatment can help manage symptoms and prevent or delay the progression of the disease.
 
  • Regular Exercise: Staying active is key to maintaining mobility and flexibility. A physical therapist can guide you on exercises that are safe and effective for people with AS.
  • Maintain Good Posture: Paying attention to posture during daily activities can help reduce stress on the spine and other joints.
  • Early Medical Intervention: If you experience symptoms such as chronic back pain or stiffness, early consultation with a healthcare provider can help identify the condition and start treatment early.

Outlook for Ankylosing Spondylitis

Ankylosing spondylitis is a lifelong condition, but with the right treatment, people with AS can manage their symptoms and maintain a good quality of life. Early diagnosis and aggressive treatment can help reduce pain, prevent deformities, and slow the progression of the disease.
 
In some cases, the disease may lead to significant spinal fusion, making it harder to bend and move. However, with the use of medications, physical therapy, and lifestyle adjustments, many individuals with AS are able to lead active lives.
 
Regular follow-up with a healthcare provider is important to monitor the progression of the disease and adjust treatments as necessary.

Further information

Last updated19 May 2025
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