Ankylosing Spondylitis

Axial Spondyloarthopathy
1. Any Spondyloarthropathy that invoves the spine
Ankylosing Spondylitis
1. Radiographically positive cases of Axial Spondyloarthopathy

Axial Spondyloarthropathy is the most common Spondyloarthropathy subtype
Strong Association with HLA-B27
1. HLA-B27 positive in up to 95% of AS cases
2. Only 2% of HLA-B27 develop Ankylosing Spondylitis
3. Populations with higher IncidenceHLA-B27 positive
  1. Native Americans
  2. Asian populations (except Japanese)
  3. European and United States Caucasian
Men more often affected by ration of 3:1
Onset between Puberty and age 40-45 years
Low Prevalence Groups
1. South American Indians
2. Japanese
3. African-Americans

Back pain
1. Starts with dull low back radiating to gluteal area
2. Progresses up spine to ultimately involve neck
Onset before age 40-45 years (may occur as early as 13)
Insidious onset
Duration longer than 3 months
Pain worse in the morning
Morning stiffness lasts longer than 30 minutes
Pain decreases with Exercise or activity
Pain provoked by prolonged inactivity or lying down
Pain accompanied with constitutional Symptoms
1. Anorexia
2. Malaise
3. Low grade fever

Monoarticular Arthritis or Oligoarticular Arthritis
Asymmetric and nonerosive Arthritis
Common joint involvement
1. Inflammatory low back (esp. Sacroiliitis)
  1. Onset at the sacroiliac joint (typically bilateral)
  2. Progresses to involve the lumbar and Cervical Spine
2. Large joints:
  1. Shoulders
  2. Hips (Hip Flexion contractures with rigid gait)
  3. Peripheral joint involvement more common in women
    1. Women have less axial skeleton involvement
Costosternal Pleuritic Chest Pain
Heel Pain
1. Achilles tendon insertion at Calcaneus
2. Plantar fascia insertion at Calcaneus

Acute Anterior Uveitis (Nongranulomatous)
1. Occurs in 20-40% of Ankylosing Spondylitis
Microscopic Colitis (often asymptomatic)
1. Occurs in 25-40% of Ankylosing Spondylitis
Cardiac involvement rare
1. Aortic Insufficiency
2. Aortitis
3. Conduction defects
4. Arrhythmias
Pulmonary Involvement
1. Restrictive Lung Disease
  1. Restricted costovertebral mobility
2. Apical lobe fibrosis
Neurologic Involvement
1. Spine Fractures or dislocations
2. Cauda Equina Syndrome
3. Atlantoaxial subluxation

Observation of back
1. Lumbar lordosis flattened
2. Thoracic kyphosis exaggerated
3. Cervical Spine hyperextended
Tests for Sacroiliac Joint Inflammation
1. Gaenslen's Test
2. Patrick's Test
Tests for reduced range of motion loss at Lumbar Spine
1. Schober's Test (low efficacy)
2. Decreased lateral bending and lumbar extension
Other findings
1. Peripheral Arthritis (esp. lower extremities) in 50% of Axial Spondyloarthropathy patients
2. Enthesitis
  1. Achilles tendon
  2. Plantar fascia
  3. Chest wall

Anteroposterior Pelvis XRay
1. Usually sufficient as only XRay confirmation
2. Reveals bilateral and symmetric Sacroiliitis
  1. Sclerosis may be present (usually not in children)
  2. Later findings include erosions or SI joint fusion
Spine XRay other findings
1. Initial
  1. Bony sclerosis appears as squaring of Vertebrae
2. Next
  1. Osteitis of Vertebral margins
3. Late
  1. Annulus fibrosus ossifies
  2. Syndesmophytes between Vertebrae and intervertebral discs
    1. Classic "Bamboo" spine (<10%) appearance
    2. Progresses up spine
Special XRay views
1. Ferguson's View (specialized sacroiliac view)
Other studies with limited indications
1. Bone Scan
2. CT or MRI spine
  1. Consider SI MRI when clinical suspicion high, but non-diagnostic XRay

HLA-B27 Assay
1. Nonspecific: Present in 6% of U.S patients (up to 10% of Caucasians)
2. Not recommended for routine testing
  1. However, present in 85-90% of Axial Spondyloarthropathy
Acute phase reactants
1. General
  1. Increased in up to 70% of Ankylosing Spondylitis (30-50% in some studies)
  2. Not correlated with disease activity or severity
2. Markers
  1. C-Reactive Protein (CRP)
  2. Erythrocyte Sedimentation Rate (ESR)

First Line: NSAIDS
1. Ibuprofen
2. Naproxen
Second-Line: Tumor-Necrosis Inhibitors (TNF Inhibitors)
Second-Line: Miscellaneous
1. Anti-Interleukin-17 Inhibitors (e.g. Secukinumab)
2. Janus Kinase Inhibitors
Other agents that may be considered in refractory cases (mixed efficacy)
1. Sulfasalazine 2-4g/day divided doses
  1. Effective peripheral Arthritis
  2. Less effective for axial skeleton symptoms
2. Methotrexate
  1. Effective for peripheral but not axial Arthritis
3. Pamidronate (Aredia) IV
4. Local Corticosteroids injection
  1. For persistent synovitis and enthesopathy
Medications to avoid
1. Avoid long term Systemic Corticosteroids
  1. Not generally effective in Ankylosing Spondylitis
2. Avoid gold and Penicillamine