Ankylosing Spondylitis (AS)

This is the primary inflammatory polyenthesitis of the spine. Inflammation in most other tissues leads to their destruction but this not the case in the spine. The opposite occurs whereby enthesitis is associated with florid tissue repair and new bone formation at entheses. When inflammation is controlled in Rheumatoid Arthritis then joint damage usually stops but in Ankylosing Spondylitis damage as determined by loss of function due to the bones knitting together may actually get worse. Key to understanding these processes is the central role of the enthesis in health and disease.

AS Overview

Ankylosing Spondylitis is associated with enthesitis at multiple sites. It is the commonest inflammatory polyenthesitis of the spine. It has a predisposition to involve entheses of the spine from the low back where it most typically starts ....

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Enthesitis at AS Onset

Although AS typically starts in the low back it can start at other sites throughout the body. This page explains why that is the case and is especially important ....

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The Sacroiliac Joint

The sacroiliac joints links the spine to the pelvis and is a major cause of back pain and especially pain in the low back. The sacroiliac joint is lined by synovium and produces lubricating synovial fluid ...

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Why did my AS start in the Sacroiliac Joint

Ankylosing spondylitis (AS) typically starts with low back pain in the sacroiliac joint. This page helps explain why ankylosing spondylitis starts in the sacroiliac joint ....

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Chest Pain in AS

The chest wall is an incredibly complex region with multiple insertion points that may become inflamed in Ankylosing Spondylitis and related disorders. The purpose of this page is to explain to both patients and doctors why chest wall enthesitis is frequently not recognised ....

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Eye Disease in AS

Acute anterior uveitis causes pain, redness and loss of vision due to inflammation in the anterior part of the eye. Acute anterior uveitis is associated with the inflammatory diseases collectively known as the seronegative spondyloarthropathies (SpA). These arthritic conditions ....

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Bone Erosion in AS

Bone erosion is a process whereby the surface of a bone (the bone cortex) is degraded or eroded and is most typically seen in the setting of inflammation. In this context specialised cells termed osteoclasts ....

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New Bone Formation in AS

New bone formation is the major cause of permanent disability in Ankylosing Spondylitis (AS). Although new bone formation occurs both in the peripheral and axial (spinal) skeleton, it is the spinal involvement that is ....

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Aortic Disease in AS

The aorta is the major blood vessel that is attached to the heart. At the root or point of attachment to the heart, there is a specialised structure called the aortic valve. The Seronegative Spondyloarthropathies and Ankylosing Spondylitis ....

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The Gut in AS

Gut inflammation typically is associated with joint pain and swelling. There is increasing evidence that the major site of involvement in the joints in the arthritis associated with Ulcerative Colitis ....

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Lung Disease in AS

Fortunately disease of the lung itself that causes significant damage that leads to shortness of breath is uncommon in Ankylosing Spondylitis (AS). The major way in which AS causes breathlessness ....

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The Hip in AS

After sacroiliac and spinal involvement the next most common joints to be afflicted in AS are the large joints including the hips. Hip disease can be difficult to recognise because the joint is located deep .....

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The Shoulder in AS

Shoulder joint involvement is a common features of AS but it does not generally cause the same degree of disability as spine or hip involvement. The medical knowledge relating .....

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The Foot and Ankle in AS

Patients with AS may experience easily recognised types of enthesitis of the foot. These most typically include Achilles Enthesitis and Plantar fasciitis. The foot and ankle are also sites of ....

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Mechanical Stress in AS

The role of movement and the forces generated by walking, running and other activities and the ability of strenuous exercise to cause tissue damage that might trigger AS is a new area of research. The role of mechanical factors ....

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Spinal Inflammation in AS

The major cause of disability in long standing Ankylosing Spondylitis (AS) is spinal inflammation that may result in subsequent new bone formation. This page explains spinal inflammation in AS that is largely linked to enthesitis ....

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Treatment of enthesitis in AS

From having no proven therapies, with the possible exception of non-steroidal anti-inflammatory drugs which are of limited value, the treatment of the spinal polyenthesitis and associated osteitis (bone inflammation) ....

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Flipping Buttock Pain

A major feature of Ankylosing Spondylitis (AS) is deep seated buttock pain that flips from side to side. Frustratingly, when the doctors examine a patient with such pain, there may be nothing to find .....

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Mechanical Model of AS

This page explains the mechanical model for Ankylosing Spondylitis and the related Spondyloarthropathies. This scientific theory was published at the turn of the millennium and is explained here in terminology for the non-expert ....

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Injury and Occupation in AS

Ankylosing Spondylitis (AS) localises to sites of high mechanical stressing at entheses and the bone adjacent to fibrocartilage at sites including the sacroiliac joint. Research in man into enthesitis and animal model data increasingly supports ....

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