Ankylosing spondylitis

Ankylosing spondylitis (AS) is a type of inflammatory arthritis in which there is a long-term inflammation of the joints of the spine

Primary Area Effected by Ankylosing Spondylitis

Ankylosing spondylitis is a form of ongoing joint inflammation (chronic inflammatory arthritis) that primarily affects the spine.

Ankylosing spondylitis lumbar spine

Cause

No one knows the cause of ankylosing spondylitis. Studies show, however, that both genes and things in our environment may lead to the development of the disease.

Risk factors

• Anyone can get ankylosing spondylitis; however, certain factors may increase your risk for developing the disease, such as:

• Family history and genetics. If you have a family history of ankylosing spondylitis, you are more likely to develop the disease.

• Age. Most people develop symptoms of ankylosing spondylitis before age 45.  

• Sex. Men are more likely to have ankylosing spondylitis than women.

• Other conditions. People who have Crohn’s disease, ulcerative colitis, or psoriasis may be more likely to develop the disease.

Signs and symptoms

Illustration depicting ankylosing spondylitis

AS is characterized by back pain and stiffness that typically appear in adolescence or early adulthood. Over time, back movement gradually becomes limited as the bones of the spine (vertebrae) fuse together. This progressive bony fusion is called ankylosis.

Progressive disease

• As the disease progresses, loss of spinal mobility and chest expansion, with a limitation of anterior flexion, lateral flexion, and extension of the lumbar spine, are seen. Systemic features are common, with weight loss, fever, or fatigue often present.
• Pain is often severe at rest but may improve with physical activity, but inflammation and pain to varying degrees may recur regardless of rest and movement.

Other joint and systemic involvement

• Arthritis in the hips and shoulders may also occur. When the condition presents before the age of 18, it is more likely to cause pain and swelling of large lower limb joints, such as the knees.
• About 40% of people with AS will also experience inflammation of the anterior chamber of the eye
• Inflammation of the prostate occurs with increased frequency in men.
• Cardiovascular involvement may include inflammation of the aorta, aortic valve insufficiency or disturbances of the heart's electrical conduction system.
• Lung involvement is characterized by progressive fibrosis of the upper portion of the lung.

Pathophysiology

The ankylosis process

• Ankylosing spondylitis (AS) is a systemic rheumatic disease, meaning it affects the entire body.
• Approximately 90% of people with AS express the HLA-B27 genotype, meaning there is a strong genetic association.
• 1–2% of individuals with the HLA-B27 genotype develop the disease.

HLA-B27 association

The association of AS with HLA-B27 suggests the condition involves CD8 T cells, which interact with HLA-B.

Bamboo spine

"Bamboo spine" develops when the outer fibers of the fibrous ring (anulus fibrosus disci intervertebralis) of the intervertebral discs ossify, which results in the formation of marginal syndesmophytes between adjoining vertebrae.

Bechterew-Kyphose

Diagnosis

34-year-old male with AS. Inflammatory lesions of the anterior chest wall are shown (curved arrows). Inflammatory changes are seen in the lower thoracic spine and L1 (arrows).

Schober's test

The Schober's test is a useful clinical measure of flexion of the lumbar spine performed during the physical examination.

Treatment

There is no cure for AS, although treatments and medications can reduce symptoms and pain.

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  Ankylosing spondylitis

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  Ankylosing spondylitis

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  Bone Density Test

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  Ankylosing spondylitis

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  Costovertebral Ankylosis

Medication

• The mainstay of therapy in all seronegative spondyloarthropathies are anti-inflammatory drugs, which include NSAIDs such as ibuprofen, phenylbutazone, diclofenac, indomethacin, naproxen and COX-2 inhibitors, which reduce inflammation and pain.

Medications used to treat the progression of the disease include the following:

• Disease-modifying antirheumatic drugs (DMARDs) such as sulfasalazine can be used in people with peripheral arthritis. For axial involvement, evidence does not support sulfasalazine.
• Tumor necrosis factor-alpha (TNFα) blockers (antagonists), such as the biologics etanercept, infliximab, golimumab and adalimumab, have shown good short-term effectiveness in the form of profound and sustained reduction in all clinical and laboratory measures of disease activity.
• Anti-interleukin-6 inhibitors such as tocilizumab, currently approved for the treatment of rheumatoid arthritis
• Interleukin-17A inhibitor secukinumab is an option for the treatment of active ankylosing spondylitis that has responded inadequately to (TNFα) blockers.

Surgery

In severe cases of AS, surgery can be an option in the form of joint replacements, particularly in the knees and hips. Surgical correction is also possible for those with severe flexion deformities (severe downward curvature) of the spine, particularly in the neck, although this procedure is considered very risky. In addition, AS can have some manifestations which make anesthesia more complex. Changes in the upper airway can lead to difficulties in intubating the airway, spinal and epidural anesthesia may be difficult owing to calcification of ligaments, and a small number of people have aortic insufficiency. The stiffness of the thoracic ribs results in ventilation being mainly diaphragm-driven, so there may also be a decrease in pulmonary function.

Physical therapy

Though physical therapy remedies have been scarcely documented, some therapeutic exercises are used to help manage lower back, neck, knee, and shoulder pain.

• Low intensity aerobic exercise
• Transcutaneous electrical nerve stimulation (TENS)
• Thermotherapy
• Proprioceptive neuromuscular facilitation (PNF)
• Exercise programs, either at home or supervised
• Hydrotherapy
• Group exercises eg Pilates

Other names

• Bechterew disease
• Marie-Struempell disease
• spondylarthritis ankylopoietica
• spondylitis ankylopoietica
• spondylitis, ankylosing
• spondyloarthritis ankylopoietica

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