Ankylosing Spondylitis
Ankylosing spondylitis (AS) is a form of arthritis that affects the spine and sacroiliac joints. It is characterised by chronic (long-term) inflammation, causing pain and stiffness in the back. In severe cases, the affected joints may become fused causing the whole spine to become curved and inflexible.
In most cases AS is a mild condition but can be severe and debilitating. It is most likely to develop between the ages of 13 and 35 years, but can develop at any age. It affects men approximately three times more often than women.
AS may also be known as rheumatoid spondylitis, Marie-Strumpell Disease and Von Bechterew-Strumpell Syndrome.
AS belongs to a group of inflammatory arthritic conditions of the spine called spondyloarthropathies. Unlike most other types of arthritis where the inside of the joint is inflamed, the spondyloarthropathies involve inflammation on the outside of the joint where the ligaments, joint capsule and tendons attach to bone (enthesis). In AS there is inflammation of the enthesis around the spinal joints.
Early symptoms of AS include mild back pain and stiffness. These may be most noticeable in the early morning and tend to wear off during the day and with activity. The pain may start as a mild ache in the buttocks and may radiate to the back of the thighs or down the legs.
Symptoms tend to develop gradually over a period of weeks or months but can sometimes develop rapidly.
AS can affect any part of the spine and may progress to the ribcage, causing chest pain, limiting chest expansion, and making breathing difficult.
AS is a systemic condition, meaning it can have an impact on the whole body.
Systemic symptoms can include:
- Fatigue
- Mild fever
- Loss of appetite (with resulting weight loss)
- Night sweats
- In rare cases AS can be associated with problems in other parts of the body, including:
- Damage to the valves in the heart.
- Thickening and scarring of the lobes of the lungs (lobular fibrosis)
- Inflammation in the gastrointestinal tract eg: colitis.
- Inflammation of the iris in the eye, in approximately 25% of patients.
- Very rarely, kidney failure, and heart block
AS is characterised by periods in which symptoms are absent and periods in which symptoms are problematic (in other words, remissions and relapses).
The exact cause of AS is unclear. It is thought to be an autoimmune disease - where the body’s own immune system attacks the body’s tissues causing inflammation and tissue damage.
Genetic (inherited) factors appear to influence development of AS. Approximately 90% of people diagnosed with AS have a gene called HLA-B27. However only about 10 – 15% of people with the gene will go on to develop AS. Approximately one in five individuals with AS also has a relative with the condition.
There is some evidence that exposure to a certain intestinal bacteria stimulates an abnormal immune reaction, which results in the development of AS. Environmental factors may also play a role.
Early diagnosis of AS is important if fusion of the joints and permanent stiffening of the spine are to be avoided. It can be difficult to diagnose in the early stages as symptoms may be attributed to more common causes of back pain.
A doctor will evaluate the following when diagnosing the condition:
- A full medical history, including any family history of AS
- Discussion of current symptoms including a history of back pain
- The age of the patient when the pain started
- Physical assessment
- X-rays – which may show signs of inflammation of the joints in the spine
- Blood tests – which may show the presence of the HLA-B27gene and a raised ESR (erythrocyte sedimentation rate) and a reactive protein which indicates inflammation
When a diagnosis of AS is confirmed, patients may be referred to a rheumatologist - who specialises in treating arthritis, and/or an orthopaedic surgeon - who specialises in surgically correcting joint or bone disorders.
While AS cannot be cured, treatment aims to minimise the symptoms and prevent long term complications such as fusion of the joints.
Essentially the goals of treatment are to:
- Reduce inflammation
- Reduce pain
- Maintain mobility
To achieve these goals a combination of treatments is usually recommended. These include:
Medications
Medications used in the treatment of AS include non steroidal anti-inflammatory drugs (NSAIDs) which work by treating pain and inflammation. These are vital in the treatment of AS and are usually very effective. Larger doses than normal are often required in the treatment of AS. Side effects of older types of NSAIDs include damage or irritation of the stomach lining.
Corticosteroids may also be used to reduce inflammation. They are most useful when injected directly into an inflamed joint..
Exercise
Exercise is vital in the management of AS — especially exercise that maintains movement of the spinal joints and strengthens the muscles in the back and neck. Swimming is often recommended as it exercises all of these joints and muscles. A physiotherapist can recommend an appropriate exercise regime. Individuals with AS also need to have periods of rest and avoid exhaustion.
Posture
Maintaining correct posture is vital for people with AS. Keeping the spine straight plays an important role in preventing complications. Using a firm mattress without pillows can help maintain correct posture when sleeping
Surgery
Severe disability and deformity are unusual in AS but in cases where pain is extreme and deformities are disabling, surgery may be appropriate. Commonly this involves hip joint replacements. However surgery to help straighten the spine may be required if curvature of the spine is severe.
Alternative therapies
Some people find therapies such as homeopathy, acupuncture and naturopathy are helpful in managing the symptoms of AS.
Not smoking, maintaining a healthy body weight and having a healthy balanced diet are also important factors in managing the condition.
Ankylosing spondylitis cannot be prevented but in most cases an independent life can be maintained. Research is continuing to try to understand the development of the disease so that in time a cure may be possible.
For further information and support please contact your GP or practice nurse, or contact Arthritis New Zealand:
Arthritis New Zealand
PO Box 10-020
Wellington
Ph: (04) 472 1427
Fax: (04) 472 7066
Website:
www.arthritis.org.nz
For branch offices please refer to the local telephone directory or the Arthritis New Zealand website.
Arthritis Foundation of New Zealand (2000) Ankylosing spondylitis (Pamphlet) Wellington: Arthritis Foundation of New Zealand (Inc)
Barone, J. (2006) Ankylosing Spondylitis. The Gale Encyclopedia of Medicine. Third Edition. Jacqueline L. Longe, Editor. Farmington Mills, MI. Thompson Gale.
Gill, M. (ed.) (2000) HLA-B27 antigen (human leucocyte antigen B27). In Gill, M. A handbook for the interpretation of laboratory tests (3rd ed.) (p213) Auckland: Diagnostic Medlab Ltd.
Hoi, A and Littlejohn, G (2002) Management of Ankylosing Spondylitis. New Ethicals Journal, July, p49
Schiller, A.L. & Teitelbaum, S.L. (1999) Bones and joints. In E. Rubin & J.L. Farber (eds.) Pathology (3rd ed.) (pp1336 – 1413) Philadelphia: Lippencott-Raven Publishers
Wellington Regional Rheumatolgy Unit (Date unknown) Ankylosing spondylitis Wellington: New Zealand Rheumatology Association.
Last Reviewed – 13/08/07