Ankylosing Spondylitis

Ankylosing spondylitis is a chronic, autoimmune inflammatory arthritis predominately affecting the axial skeleton, including the spine and sacroiliac (SI) joints. Ankylosing spondylitis is a type of seronegative spondyloarthropathy, which is a group of disorders characterized by negative labs (seronegative), inflammatory back pain, and enthesitis (pain and tenderness where ligaments and tendons connect to the bone). Vertebrae of the spine may fuse over time leading to decreased range of motion and a stooped posture.

• Alternating buttock pain
• Back pain for greater than 3 months
• Fatigue
• Gradual onset
• Greater than 30 minutes of morning stiffness
• Improvement with exercise/activity
• Pain worst during the second half of the night and into the morning
• Typical onset before age 45

• Ankylosing Spondylitis (AS), also known as radiographic ankylosing spondylitis (axSpA), with hallmark radiographic findings including sacroiliitis and fusion of the spine.
• Non-radiographic axial spondyloarthritis (nr-axSpA) is characterized by typical clinical features without structural damage present on x-ray.

• Joints
  • Peripheral joints: approximately 1/3 of AS patients will develop joint symptoms outside of the axial skeleton, especially prevalent in the knees, hips, and ankles. Presentation is usually asymmetric.
  • Enthesitis: inflammation at ligament or tendon insertions. Most commonly affect the Achilles tendon (ankle) and plantar fascia (feet).
  • Dactylitis: swelling of an entire finger or toe and commonly called “sausage digit”.
• Eyes
  • Uveitis: inflammation of the eye causing pain, redness, and occasionally vision loss.
• GI tract
  • Irritable Bowel Disease: IBD (Crohns, Ulcerative Colitis) may occur in a small portion of patients with AS. Symptoms include diarrhea and abdominal pain.
• Cardiovascular system: chronic inflammation increases the overall risk for heart attack and stroke
• Lungs:
  • Structural: fusion of the spine and stooped posture may lead to obstructive sleep apnea and shortness of breath from restricted movement.
  • Inflammation: chronic inflammation may lead to pulmonary conditions like interstitial lung disease.

• Labs:
  • HLA-B27: approximately 70-90% of AS patients will test positive for this antigen. It is a disease marker and indicates likelihood of developing the disease.
  • CRP & ESR: both tests are indicators of systemic inflammation and are used to both diagnose and monitor disease.
• Diagnostic Imaging:
  • X-ray and MRI are recommended as first-line imaging for diagnosis. Key findings include erosions, flowing syndesmophytes, ankylosis, and sclerosis.

• Physical Therapy
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Biologic medications
  • TNF inhibitors
  • IL-17 inhibitors
  • JAK inhibitors

• Adequate sleep
• Regular exercise
  • Physical inactivity is associated with worse outcomes
• Smoking cessation
  • Tobacco use is strongly associated with increased disease activity
• Stress management