From the Guidelines
Ankylosing spondylitis (AS) presents with characteristic clinical features that typically begin in early adulthood, including inflammatory back pain, sacroiliac joint inflammation, and a strong association with HLA-B27, as reported in the most recent study 1. The hallmark symptom of AS is inflammatory back pain, which manifests as persistent low back pain and stiffness that worsens with rest and improves with activity. This pain often awakens patients in the early morning hours and is accompanied by prolonged morning stiffness lasting more than 30 minutes. AS commonly affects the sacroiliac joints first, causing buttock pain that may alternate sides, before progressing up the spine. Some key features of AS include:
- Inflammatory back pain
- Sacroiliac joint inflammation
- Enthesitis (inflammation at tendon insertions)
- Peripheral arthritis, typically asymmetric and affecting lower limbs
- Extra-articular manifestations, such as anterior uveitis, cardiovascular complications, and pulmonary involvement As the disease advances, patients develop reduced spinal mobility and characteristic postural changes, including flattening of the lumbar spine, exaggerated thoracic kyphosis, and forward stooping posture (bamboo spine). The disease has a strong association with HLA-B27, and symptoms typically begin between ages 15-45, with males affected more frequently and severely than females, as noted in 1 and 1. However, the most recent and highest quality study 1 provides the most accurate and up-to-date information on the clinical features of AS, which is essential for diagnosis and treatment. In terms of diagnosis, imaging plays a critical role, with MRI being a key diagnostic tool, as highlighted in 1. Overall, the clinical features of AS are complex and multifaceted, requiring a comprehensive approach to diagnosis and treatment, as emphasized in 1.
From the Research
Clinical Features of Ankylosing Spondylitis (AS)
The clinical features of Ankylosing Spondylitis (AS) include:
- Chronic low back pain that typically starts before the age of 40 years 2
- Lower back, hip, and joint pain with stiffness that is worse in the morning and with inactivity 2
- Back pain and stiffness with rest, especially in the morning, which improves with exercise 3
- Pain radiating into the buttocks which may be unilateral or alternate, particularly in the early stages 3
- Large joint synovitis and features of entheseal involvement 3
- Fusion of sacroiliac joints and ankylosis of the vertebrae with the iconic "bamboo spine" on imaging 2
- Joint fusion or ankylosis, which is the sequela of either undiagnosed or untreated AS 2
- Complete fusion of the ankle joint, hindfoot, and midfoot, also known as "boot sign" 2
- Spinal pain and stiffness, which can lead to progressive thoracolumbar kyphotic deformity 4
- Degenerative vertebral lesions, known as Andersson lesions, which can cause significant mechanical pain 4