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Ankylosing Spondylitis N005
In this section
Current RMA Instruments
|Reasonable Hypothesis SOP||39 of 2021|
|Balance of Probabilities SOP||40 of 2021|
Changes from previous Instruments
- ICD-9-CM Codes: 720.0
- ICD-10-AM Codes: M45
This is an uncommon, chronic, progressive, systemic, inflammatory condition which mainly affects the spine (spondylitis) and sacroiliac joints and causes chronic back pain. There can also be manifestations outside the spine, see note below.
Confirming the diagnosis
The diagnosis is based on a combination of clinical findings, laboratory results and imaging. The diagnosis is often difficult to establish and specialist opinion will be needed. Testing will typically include HLA-B27 (a genetic marker) testing and plain X-rays or MRI of involved joints. There is no one single finding that will confirm the diagnosis.
The appropriate medical specialist is a rheumatologist.
Additional diagnoses covered by SOP
- Axial spondyloarthritis
- Marie-Strumpell disease
- Von Bechterew’s disease
Additional diagnoses which may be covered (further information required)
- HLA B27 spondyloarthropathy
- Inflammatory sacroilitis
- Sero-negative spondyloarthropathy
Conditions excluded from SOP
- Osteoarthritis or spondylosis* of spine
- Spondyloarthropathy – due to reactive arthritis*, psoriatic arthritis* or inflammatory bowel disease*
- Rheumatoid arthritis of the spine*
* another SOP applies
Onset is typically insidious and before the age of 45 (peak is between 20 and 30 years). The most common presentation is with chronic dull pain in the lower back or buttock.
The only SOP worsening factor is for inability to obtain appropriate clinical management. There is no curative treatment but there are medications that can slow or stop the progress of the disease. The clinical course is variable.
Note: Other manifestations of ankylosing spondylitis
This systemic disease may have other manifestations:
- Inflammation in other joints:
- hip and shoulder
- peripheral joints
- costovertebral, chostochondral, sternoclavicular joints
- Enthesitis - inflammation of some tendon-bone insertions
- Dactylitis - inflammation and swelling of fingers
- Eye changes – anterior uveitis
- Cardiac problems – aortic regurgitation; conduction abnormalities
- Pulmonary changes – apical pulmonary fibrosis
There may also be complications arising from the spinal pathology such as: spinal stenosis with radiculopathy and myelopathy; localised osteoporosis; and spinal compression fractures.