What is ankylosing spondylitis?

Ankylosing spondylitis is a form of inflammatory arthritis. It affects the joints of the spine, in particular the sacroiliac joint at the bottom of the spine. Ankylosing spondylitis causes the swelling of the ligaments, discs and joints between the vertebrae of the spine. Symptoms include pain and stiffness in the lower back and over time, fusion of the vertebrae can occur.

discs

Intervertebral discs - layers of cartilaginous material that act as cushions between the vertebrae and the joints in the spine, enabling the spine to bend and twist.

Ligaments

Short, flexible fibrous tissue that connects the bones and cartilage of joints.

Sacroiliac joint

The joint that connects the spine to the pelvis.

Vertebrae

The bones that make up the spinal column.

Spine

The bony structure that comprises the individual vertebrae that enclose and protect the spinal cord and nerves located in the middle.

Inflammatory arthritis

A group of conditions in which the body's immune system mistakenly attacks the joints. It can also affect other tissues and organs.

Causes

The specific cause of ankylosing spondylitis is unknown, although genetic factors appear to play a role. The presence of a specific gene that produces the antigen HLA-B27, is found in nine out of 10 people with ankylosing spondylitis, although there are people with the gene that do not develop the condition. [1] It is therefore thought that other factors are involved in triggering ankylosing spondylitis.

Ankylosing spondylitis can begin to develop from the age of 15 years and generally affects young adults before the age of 35 years. The condition begins with inflammation of the sacroiliac joint and facet joint. Over time, bony growths can begin to form and cause fusion of vertebrae, causing limited movement and pain in the lower back.

Ankylosing spondylitis causes the swelling of the ligaments, discs and joints between the vertebrae of the spine.  

Antigen

A substance or particle that is recognised as foreign by the immune system, stimulating an immune response.

discs

Intervertebral discs - layers of cartilaginous material that act as cushions between the vertebrae and the joints in the spine, enabling the spine to bend and twist.

Facet joint

Small joints that are located between and behind each vertebrae in the spine.

Gene

A unit of inheritance (heredity) of a living organism. A segment of genetic material, typically DNA, that specifies the structure of a protein or related molecules. Genes are passed on to offspring so that traits are inherited, making you who you are and what you look like.

Genetic

Related to genes, the body's units of inheritance or origin.

HLA-B27

A type of antigen associated with particular inflammatory diseases.

Inflammation

A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.

Ligaments

Short, flexible fibrous tissue that connects the bones and cartilage of joints.

Sacroiliac joint

The joint that connects the spine to the pelvis.

Vertebrae

The bones that make up the spinal column.

Spine

The bony structure that comprises the individual vertebrae that enclose and protect the spinal cord and nerves located in the middle.

1. Golder, V. (2013) Ankylosing spondylitis: an update. Australian Family Physician 42:780-784. Accessed 16 October 16 2014, from

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Risk factors

Risk factors associated with developing the condition include:

  • Having the HLA-B27-causing gene increases the susceptibility of developing ankylosing spondylitis;
  • Family history of the condition increases the risk of passing on the HLA-B27-causing gene, and;
  • Being male - it is three times more common in men than women. [1]

Gene

A unit of inheritance (heredity) of a living organism. A segment of genetic material, typically DNA, that specifies the structure of a protein or related molecules. Genes are passed on to offspring so that traits are inherited, making you who you are and what you look like.

HLA-B27

A type of antigen associated with particular inflammatory diseases.

1. Golder, V. (2013) Ankylosing spondylitis: an update. Australian Family Physician 42:780-784. Accessed 16 October 16 2014, from

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Signs and symptoms

The signs and symptoms of ankylosing spondylitis include:

  • Lower back pain that gradually appears over time, is worse after rest and improves after exercise;
  • Stiffness that worsens in the morning;
  • Buttock, hip or shoulder pain;
  • Limited mobility of the spine;
  • Head-forward posture or neck pain;
  • Pain in ligaments and tendons that are attached to the spine, for example, the back of the heel, and;
  • Eye pain, light sensitivity or blurred vision.

The signs and symptoms can improve, worsen, or stop entirely at irregular intervals.

Ligaments

Short, flexible fibrous tissue that connects the bones and cartilage of joints.

Tendons

Dense bands of connective tissue that attach muscles to bones.

Spine

The bony structure that comprises the individual vertebrae that enclose and protect the spinal cord and nerves located in the middle.

1. Golder, V. (2013) Ankylosing spondylitis: an update. Australian Family Physician 42:780-784. Accessed 16 October 16 2014, from

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Methods for diagnosis

Identifying ankylosing spondylitis early is important in preventing any damage to the spine. In many cases there can be a delay of 5-7 years from the time symptoms first appear to when the condition is diagnosed. [1] In addition to reviewing the medical history, diagnosis of ankylosing spondylitis can be determined by the following tests:

Blood tests

During a blood test, blood can be drawn using a needle or by a finger prick. Your blood can then be analysed to help diagnose and monitor a wide range of health conditions.

Computerised tomography

A scan that uses X-rays to create a 3D image of the body. This can detect abnormalities more effectively than a simple X-ray can.

Gene

A unit of inheritance (heredity) of a living organism. A segment of genetic material, typically DNA, that specifies the structure of a protein or related molecules. Genes are passed on to offspring so that traits are inherited, making you who you are and what you look like.

Genetic

Related to genes, the body's units of inheritance or origin.

HLA-B27

A type of antigen associated with particular inflammatory diseases.

Inflammation

A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.

Magnetic resonance imaging

A type of imaging that uses a magnetic field and low-energy radio waves, instead of X-rays, to obtain images of organs.

X-ray

A scan that uses ionising radiation beams to create an image of the body’s internal structures.

Spine

The bony structure that comprises the individual vertebrae that enclose and protect the spinal cord and nerves located in the middle.

1. Golder, V. (2013) Ankylosing spondylitis: an update. Australian Family Physician 42:780-784. Accessed 16 October 16 2014, from

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Types of treatment

Currently there is no cure for ankylosing spondylitis. The main goal of treatment is to maintain a good quality of life by managing the symptoms and reducing the progression of the condition. Treatments include medications, physiotherapy and surgery.

Medications

Medications used in the treatment of ankylosing spondylitis include:

  • Non-steroidal anti-inflammatory drugs (NSAIDs) to reduce inflammation and control pain and stiffness;
  • Disease-modifying antirheumatic drugs (DMARDs), which can slow the progression of the condition;
  • Tumour necrosis factor (TNF) inhibitors to control inflammation, and;
  • Corticosteroids.

Physiotherapy

Physiotherapy is also commonly used to manage ankylosing spondylitis. This can include using specific exercises to reduce the pain and increase the strength and flexibility of the muscles and tendons in the affected area. Your doctor or physiotherapist can tailor an exercise program and other therapies, such as hydrotherapy, to help improve mobility of the spine.

Surgery

In most cases, surgery is not necessary, but can be utilised if there is extreme pain or joint damage. Joints can be surgically fused or repaired, depending on the location and degree of damage to a joint.

Antirheumatic

Drugs used to treat inflammatory arthritis.

Corticosteroids

A medication that resembles the cortisol hormone produced in the brain. It is used as an anti-inflammatory medication.

Hydrotherapy

A water-based type of therapy, used for relaxation and physical rehabilitation.

Inflammation

A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.

NSAIDs

Non-steroidal anti-inflammatory drugs are commonly used to manage arthritis-related pain and inflammation and other musculoskeletal disorders. NSAIDs include aspirin and ibuprofen.

Physiotherapist

A healthcare professional trained in treating injury or disability with physical remedies, such as massage or exercise.

Tendons

Dense bands of connective tissue that attach muscles to bones.

Spine

The bony structure that comprises the individual vertebrae that enclose and protect the spinal cord and nerves located in the middle.

1. Golder, V. (2013) Ankylosing spondylitis: an update. Australian Family Physician 42:780-784. Accessed 16 October 16 2014, from

External link

Potential complications

In severe forms of ankylosing spondylitis, it is possible for sections of the spine to become fused, causing stiffness and immobility. This can cause the natural curves of the spine to straighten, forcing the body into a hunched position. The rib cage can also become stiff, which can reduce the capacity of the lungs and cause breathlessness. Osteoporosis is a common complication, which can increase the risk of sustaining a fracture.

Ankylosing spondylitis can also increase the risk of developing heart disease and uveitis, a condition involving inflammation of the eye.

Heart disease

A class of diseases that involves the dysfunction of the heart and/or the blood vessels.

Fracture

A complete or incomplete break in a bone.

Inflammation

A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.

Spine

The bony structure that comprises the individual vertebrae that enclose and protect the spinal cord and nerves located in the middle.

Uveitis

Inflammation of the uvea, the middle inner layer of the eye consisting of the iris, ciliary body and choroid.

1. Golder, V. (2013) Ankylosing spondylitis: an update. Australian Family Physician 42:780-784. Accessed 16 October 16 2014, from

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Prognosis

The prognosis can depend on how early the condition is diagnosed. In some cases, only mild symptoms are experienced at irregular intervals and full physical activity is possible. In other cases, symptoms can be more frequent and complications, including spinal fusion, can occur. Treatment with medications and physiotherapy are important, after a confirmed diagnosis, to achieve the best outcome.

1. Golder, V. (2013) Ankylosing spondylitis: an update. Australian Family Physician 42:780-784. Accessed 16 October 16 2014, from

External link

Prevention

There are no specific ways to prevent ankylosing spondylitis. It is, however, possible to slow its progression and minimise risk of developing complications through early diagnosis and timely use of specific treatments. 

1. Golder, V. (2013) Ankylosing spondylitis: an update. Australian Family Physician 42:780-784. Accessed 16 October 16 2014, from

External link