Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory joint disease that can gradually affect the joints and ligaments of the spine, as well as other parts of the body. Classically, the primary site of involvement is both sides of the sacroiliac (SI) joints which then ascends the spine into the thoracolumbar region, rib articulations and the cervical spine. Fusion of the bones and ossification of ligaments in the spine generally leads to the loss of the natural curvature of the spine (becoming more hunched), and its mobility – this is also usually accompanied with pain due to inflammation. While AS commonly affects the axial skeleton, it is also known to affect the appendicular skeleton in approximately one-third of patients with AS, such as the knees and hips (arthritis), and Achilles tendon (enthesitis).

Meaning: ‘Ankylosis’ means the abnormal stiffening and reduction of mobility of a joint due to fusion of the bones. ‘Spondylitis’ can be better understood as the inflammation of the vertebrae (spinal bones).

Aetiology

The specific cause to AS is still unknown at the moment, though AS has been linked with a gene known as human leukocyte antigen B27 (HLA-B27). It is thought that carrying the gene may make someone more vulnerable to developing the disease, and it may also be triggered by one or more environmental factors, but it is still unknown what these are. Thus, testing positive for this gene does not necessarily mean that one would develop AS because only 1-2% of people with the gene will develop the disease.

Risk Factors

However, AS has a strong familial tendency in which the HLA-B27 gene can be inherited from another family member. If a parent has AS and the HLA-B27 gene, then there is a 50% chance of passing the gene down to any offspring – about 5-20% of children with this gene will then go on to develop AS. Males are also more likely to develop this disease than females with a ratio of 3:1.

Presenting Symptoms

The symptoms of AS can vary from person-to-person, but they usually develop slowly, over several months or years. AS usually first starts to develop during later teenage years or early adulthood, with peak onset at 15-25 years of age. Most patients experience mild, continuous episodes of pain and stiffness with periods of remission. Symptoms to look out for:

Fatigue
Back pain and stiffness that gets better with activity or exercise but does not improve or becomes worse with inactivity or rest
Morning stiffness in the affected region that lasts for more than 30 minutes
Pain and stiffness that is worse in the morning and at night
Pain around the buttocks
Chest pain and difficulty in expanding the chest when inhaling deeply
Pain and swelling in other parts of the body

Possible Complications

In up to 40% of patients with AS, AS can also manifest in body parts which do not make up the joints (extra articular), such as the eye (ureitis) and heart. Other possible complications of AS include:

Osteoporosis
Spinal fractures (commonly at the thoracolumbar and cervicothoracic junctions, can occur minimal trauma)
Cardiovascular diseases
Chest infections
Inflammatory bowel disease
Neurological involvement
Kidney disease (rarely)

Assessment and Tests

If you have persistent symptoms of AS, you should make an appointment with your primary healthcare provider. Given that AS can present as a mechanical issue, chiropractors are trained to differentiate if a condition is mechanical or pathological in nature. This is done by taking a detailed history of your complaint before performing suitable tests during the physical examination. Further testing such as a blood test to detect the HLA-B27 gene, and imaging such as X-ray and MRI to visualise changes in the SI joints and/or spine may also be warranted.

Pain Management

Currently, there is no cure for AS. An early and timely referral to a specialist is a must to confirm the diagnosis so that treatment can begin as soon as possible. Medication may be prescribed to manage pain and inflammation. In rare cases, surgery may be required to replace a severely damaged joint, or to correct a badly bent back. Once any extra articular manifestations of the disease have been treated and/or is being accounted for, a chiropractor and/or physiotherapist can aid in the co-management of the AS patient. The aim of conservative treatment is to reduce the symptoms and possibly, slow down the progression of the disease. This is achieved by a combination of exercise therapy, and manual therapy that includes spinal manipulative therapy, myofascial therapy and mobilisation techniques. Therapeutic ultrasound, laser and interferential therapy may also be used to help with pain management.

Reference

Blausen.com staff, 2014. Medical gallery of Blausen medical 2014. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436.
McVeigh, CM., Cairns, AP., 2006. Diagnosis and management of ankylosing spondylitis. BMJ 2006; 333: 581-5.
NHS, 2019. Ankylosing spondylitis [online]. London: NHS. Available from: https://www.nhs.uk/conditions/ankylosing-spondylitis/ [Accessed August 2022].
Souza, TA., 2016. Differential diagnosis and management for the chiropractor: protocols and algorithms. 5th edition. Burlington, Massachusetts, USA: Jones and Bartlett.