Ankylosing spondylitis
Background
- Ankylosing spondylitis (AS) is a chronic inflammatory disease of the axial skeleton with variable involvement of other joints or even nonarticular structures.
- Ankylosing spondylitis is three times more common in males than females. It is usually diagnosed in young adults between the ages of 20 and 30 years.
- Often associated with other autoimmune disorders. About 90% of people with AS express the HLA-B27 genotype.
Clinical Features
- Spinal pain, particularly in the lower back, is usually the first and most common symptom of AS.
- Begins in early adulthood (before 45 years of age)
- Has a gradual onset
- Lasts longer than three months
- Is worse after rest (for example, in the morning) but improves with activity
- Can cause morning stiffness lasting more than 30 minutes
- Fatigue
- Can also be associated with anterior uvetitis, bowel ulcers and spinal fractures are 4 times more common in patients with AS
Differential Diagnosis
Lower Back Pain
- Spine related
- Acute ligamentous injury
- Acute muscle strain
- Disk herniation (Sciatica)
- Degenerative joint disease
- Spondylolithesis
- Epidural compression syndromes
- Thoracic and lumbar fractures and dislocations
- Cancer metastasis
- Spinal stenosis
- Transverse myelitis
- Vertebral osteomyelitis
- Ankylosing spondylitis
- Spondylolisthesis
- Discitis
- Spinal Infarct
- Renal disease
- Intra-abdominal
- Abdominal aortic aneurysm
- Ulcer perforation
- Retrocecal appendicitis
- Large bowel obstruction
- Pancreatitis
- Pelvic disease
- Other
Diagnosis
- There is no direct test for AS
- ESR, CRP can be elevated but not sensitive or specific for AS
- Xray lumbar/sacroiliac: The earliest changes in the sacroiliac joints shows erosions and sclerosis.
- Progression of the erosions leads to pseudo widening of the joint space and bony ankylosis AKA "Bamboo Spine."