Ankylosing Spondylitis
A chronic, inflammatory condition that typically begins in the sacroiliac region and extends up the spine.
Demographics
Age at onset: 15-35 years
Sex: male to female ratio of 10:1
Prevalence: 0.15% of male population
Clinical Presentation
• Morning stiffness, especially in the spine
• Bilateral sacroiliac tenderness
• Limited lumbar spine mobility
• Decreased chest expansion
• Occasionally, peripheral, large joint involvement
• Systemic effects in severe cases include fatigue, anorexia, weight loss, cardiovascular and pulmonary manifestations
• “question mark” deformity or “bamboo spine” in later stages characterized by increased thoracic kyphosis and decreased lumbar lordosis
Differential Diagnosis
Criteria for diagnosis include:
• Low back pain for at least 3 months; improved with exercises but not relieved with rest
• Limited lumbar spine mobility
• Decreased chest expansion below normal values for age and sex
• Bilateral sacroiliac tenderness, minimal or greater
• Unilateral sacroiliac tenderness, moderate or greater
• Lab tests: elevated sedimentation rate, absent rheumatoid factor, presence of HLA B27 antigen
• Imaging: vertebral bodies may become demineralized, calcification of the annulus fibrosus and spinal ligaments, fixed kyphosis
Clinical Bottom Line: Treat and Refer
References:
Please refer to the "Ankylosing Spondylitis" section of the reference list.
Demographics
Age at onset: 15-35 years
Sex: male to female ratio of 10:1
Prevalence: 0.15% of male population
Clinical Presentation
• Morning stiffness, especially in the spine
• Bilateral sacroiliac tenderness
• Limited lumbar spine mobility
• Decreased chest expansion
• Occasionally, peripheral, large joint involvement
• Systemic effects in severe cases include fatigue, anorexia, weight loss, cardiovascular and pulmonary manifestations
• “question mark” deformity or “bamboo spine” in later stages characterized by increased thoracic kyphosis and decreased lumbar lordosis
Differential Diagnosis
Criteria for diagnosis include:
• Low back pain for at least 3 months; improved with exercises but not relieved with rest
• Limited lumbar spine mobility
• Decreased chest expansion below normal values for age and sex
• Bilateral sacroiliac tenderness, minimal or greater
• Unilateral sacroiliac tenderness, moderate or greater
• Lab tests: elevated sedimentation rate, absent rheumatoid factor, presence of HLA B27 antigen
• Imaging: vertebral bodies may become demineralized, calcification of the annulus fibrosus and spinal ligaments, fixed kyphosis
Clinical Bottom Line: Treat and Refer
References:
Please refer to the "Ankylosing Spondylitis" section of the reference list.