Ankylosing Spondylitis (Axial Spondyloarthritis)

Original Editor - Thomas Rodeghero, Mathieu Henrotte

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Definition/Description

Ankylosing spondylitis (SA) also called Bechterew disease is an spondyloarthritis of the spine and pelvis, associated with a progressive stiffening of it. There is a bone formation at the level of the joint capsule and cartilage. The affected joint will become stiff and sensitive. Other joints such as hips, knees, ankles and shoulders may be affected by the disease, but in the greatest number of cases, the back and neck are the most affected regions. SA is often associated with other chronic inflammatory diseases such as iritis or even Crohn’s disease . This can also be seen as signs for the diagnosis of SA.

Clinically Relevant Anatomy

Ankylosing spondylitis (AS) is a chronic, multisystem inflammatory disorder of the sacroiliac (SI) joints and the axial skeleton. The disorder is often found in association with other spondyloarthropathies, including reactive arthritis, psoriasis, juvenile chronic arthritis, ulcerative colitis, and Crohn disease.  To a lesser degree, the shoulder, hip, and tempomandibular joints may also be effected.

Regions most affected by the disease are the spine and pelvis. It causes a decreased range of motion and gives the spine a bamboo aspect. Hence the name bamboo-spine.

Epidemiology /Etiology

The etiology of AS is not fully understood at this time; however, a strong genetic link has been determined.  In addition, a direct relationship between AS and the major histocompatibility human leukocyte antigen (HLA)-B27 has also been determined.  The exact role of this antigen is unknown, but is believe to act as a receptor for an inciting antigen leading to AS.

 90% of the SA patients seem to have a deficit to this antigen, but not every one that has this deficit develops the SA disease. This is why the exact role of the B27 antigen is still to be determined in the cause of ankylosing spondylitis

The most information known about the pathological process of AS is that it effects the subchondral granulation tissue and creates small lesions, which ultimately lead to joint erosion.  In the spine this occurs at the junction of the vertebrae and the anulus fibers of the discs.  These lesions in the anulus fibers eventually undergo ossification, which leads to a 'fusion' effect of the spinal segments appearing as a 'bamboo' spine.

Characteristics/Clinical Presentation

AS is predominantly seen in males in a 3:1 ratio and the onset of symptoms generally occurs in late adolescent years to early adulthood.  Onset of symptoms past the age of 45 are uncommon.

The clinical presentation is usually an insidious onset of back pain in the area of the sacroiliac (SI) joints and gluteal regions.  Morning stiffness lasting greater than 30 minutes is a common subjective complaint, as well as waking up in the second half of the night.  Pain is usually exacerbated with rest and relieve with physical activity/exercise.  Complaints of difficulty breathing at times may also be a common complaint as AS may cause a decrease in chest expansion.

Common physical findings include:

• Forward flexed, or stooped, posture
  

• Decreased spinal segmental mobility
  

• Tenderness to palpate in the SI regions
  

• Bamboo spine
  

Differential Diagnosis

Common other disorders to consider in differentially diagnosing with AS are:

• Degenerative Disc Disease
  

• Herniated Nucleus Pulposus
  

• Fractures and/or dislocation
  

• Osteoarthritis
  

• Spinal Stenosis
  
• Spondylolisthesis, Spondylolysis, and Spondylosis

Diagnostic Procedures

The diagnosis of AS is commonly made through a combination of a thorough subjective and physical examination in combination with laboratory data and imaging studies.  Common laboratory data include the presence of the HLA-B27 antigen; however, its presence is not required for a diagnosis of AS.  In addition, high C-reactive proteins (CRP) are found in approximately 75% of people with AS.But because it occurs in 10% of the white population there is a high rate of false positives. That’s why the test should be discouraged.

As a contribution tot the physical examination standard questionnaires can be used to sketch the evolution of the disease. Available questionnaires include:

• AMOR criteria
• BASDAI index
• BASFI index
• BAS-G index
  
  

The New York criteria for diagnosing AS combines physical findings with radiograph studies.  Physical findings include limitations of lumbar spine motion in 3 planes, pain (or history of pain) at the thoraco-lumbar junction or lumbar spine, and a limitation of chest expansion to 1 inch or less measured at the 4th intercostal space.  Radiographic findings are graded on a scale of 0 to 4 where 4 is considered ankylosing.  A definitive diagnosis is considered if there is a grade 3 to 4 at bilateral SI joints on radiograph with at least 1 physical finding, or grade 3 to 4 unilaterally (or grade 2 bilaterally) with 2 physical findings present.

Outcome Measures

Certain quality of life or global rating of change outcome measures may be most appropriate in the physical therapy setting as AS often effects the patient on a more general level.  However, since AS is most associated with the spine, outcome measures such as the Oswestry Disability Index (ODI) and Neck Disability Index (NDI) may also be appropriate.  Laboratory values, such as the CRP, are used to monitor the effectiveness of medication treatments.

Examination

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Medical Management

Nonsteroidal anti-inflammatory drugs (NSAIDs) and intra - articular coriticosteroids are accepted, often-used treatments for ankylosing spondylitis. Indomethacin, naproxen and diclofenac are among those most frequently used in ankylosing spondylitis.  However, as in other rheumatic diseases, NSAIDs are valuable only to improve the symptoms of spinal inflammation. There is no evidence that long-term treatment affects the radiologic outcome or function. It is widely believed that relief from pain is associated with an improved ability to exercise daily — which, over time, supports the maintenance of function and helps to prevent the joints from stiffening.
There are no established disease-modifying antirheumatic drugs (DMARDs) for ankylosing spondylitis as there are for rheumatoid arthritis. The best investigated DMARD for the treatment of ankylosing spondylitis is sulfasalazine. In two placebo-controlled studies, efficacy for peripheral arthritis but no clear effects on axial symptoms was reported.  Sulfasalazine is thereby effective for peripheral arthritis in spondyloarthritis, but there is no clear option for the axial manifestations. Much less information is available about the efficacy of other DMARDs in ankylosing spondylitis.
Very limited data on steroid treatment for ankylosing spondylitis are available. The overall efficacy is not enormous, but there are individual patients who seem to benefit in terms of reduced pain and disease activity. A positive effect on reduced bone mineral density can also be expected.
The efficacy of bisphosphonates in metastatic bone disease is well established. There have been two positive reports from small, open studies in the treatment of ankylosing spondylitis with pamidronate. Both spinal and peripheral disease were successfully treated by this intravenously applied bisphosphonate. , which is active against osteoclasts and is occasionally used for the treatment of osteoporosis.

Physical Therapy Management

Physical therapy is an essential part in the treatment of Ankylosing Spondylitis. It aims to alleviate pain, increase spinal mobility and functional capacity, reduce morning stiffness, correct postural deformities, increase mobility and improve the psychosocial status of the patients.
The Global Postural Reeducation method has shown promising short- and long-term results. It includes specific strengthening and flexibility exercises in which the shortened muscle chains are stretched. A global and functional approach is more efficient than analytic exercises in AS patients.. Muscle chains are constituted by gravitational muscles (erector spine muscles, piriformis muscle, scalene muscles, suboccipital muscles), which work synergistic with them. The analytic stretching of any individual gravitational muscle would be inefficient if not associated with a stretching of the whole muscle chain.
The GPR method obtains a greater improvement with a group physical therapy program than with home exercises. This can be explained by the mutual encouragement, reciprocal motivation, and exchange of experience in group therapy.

Since decrease in chest expansion is secondary to ankylosis in AS, there is a pulmonary involvement. This may even further decrease the low psychological status and quality of life in AS patient.. By using these exercises the chest expansion can increase, leading to better functional capacities.
-twice the normal rate of inspiration through the nose and expiration through the mouth
-normal expiration through nose and normal expiration through mouth
-respiration through the chest and abdomen
-deep breathing and then expiration through the mouth slowly
-resistance exercises for inspiratory pulmonary muscles

Self and manual mobilization improves chest expansion, posture and spinal mobility.. Both active angular and passive mobility exercises can be used in the physiological directions of the joints in the spinal column and the chest wall in flexion, extension, lateral flexion and rotation and in different starting positions (lying face down, sideways, on the back and in a sitting position). Passive mobility exercises consist of general, angular movements and specific, translatory movements.

In addition to conventional exercises (flexibility exercises for cervical, thoracic and lumbar spine, stretching exercises for the major muscle groups (erector spine, shoulder muscles, hip flexors, hamstrings and quadriceps stretch) and respiratory exercises (pursed-lip breathing, expiratory abdomen augmentation, and synchronization of thoracic and abdominal movement)) aerobic exercises such as swimming and walking are recommended. Research has shown a significant increase in chest expansion thanks to swimming exercises in chest expansion and a significant increase in pVO2 and six minute walk test in patients practicing swimming and/or walking aerobic exercises..
Aerobic exercises lead to a bigger chest expansion and therefore a better functional capacity. It also decreases the chance of respiratory failure.

Spa therapy has shown a significant positive effect on the pain, stiffness, well-being and functioning of AS-patients.. These effects are significant on short-term as well as on long-term. It is very expensive though, and the optimal length of therapy would be 4 weeks which is for many patients too long (family at home, working, etc).

Key Evidence

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Resources

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*WebMD

Clinical Bottom Line

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Recent Related Research (from Pubmed)

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References

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