N.A.S.S Dingwall Branch Information Page

Link to full Index

ANKYLOSING SPONDYLITIS

In ankylosing spondylitis there is chronic inflammation, progressing slowly to bony ankylosis, of the joints of the spinal column and occasionally of the major limb joints.

Cause.

This is unknown. The condition is distinct from rheumatoid arthritis, although it is sometimes loosely termed 'rheumatoid spine.' There is evidence of an inheritable predisposition to the disease.

Pathology.

The disease always begins in the sacro-iliac joints, whence it usually extends upwards to involve the lumbar, thoracic, and often the cervical spine. Occasionally the hips or shoulders are also affected. The articular cartilage, synovium, and ligaments show chronic inflammatory changes and eventually they become ossified. After several years the inflammatory process becomes quiescent.

 

Larger X-ray Picture of Pelvis
(Size 170KB)

Ankylosing spondylitis (characteristic fuzziness with loss of sharp outline of both the sacroiliac joints. later, these joints undergo spontaneous bony fusion, and similar changes may creep upwards, sometimes affecting the whole of the spinal column.

 

 

Clinical features.

With few exceptions the disease is confined to men, and it nearly always begins between the ages of 18 and 30. The early symptoms are pain in the lower back and increasing stiffness. Later, the pain migrates upwards. Diffuse radiating pain down one or both lower limbs is also common. On examination the predominant finding is marked limitation of all movements in the affected area of the spine ('poker back'). When the thoracic region is involved chest expansion is markedly reduced often to less than 2.5 centimetres (normal 7.5 centimetres) from ankylosis of the costo-vertebral joints. In a few cases the hips or shoulders are affected, with pain and limitation of movement.

 

Larger X-ray Picture of Spine
(Size 98KB)

Ossification of the anterior longitudinal ligament in ankylosing spondylitis In severe cases the spinal column may become rigid throughout its length.

 

 

Radiographic examination.

In the early stages there is fuzziness of both the sacro-iliac joints, so that the joint outline is no longer clearly defined. Later, the sacro-iliac joints are completely obliterated and, if the disease progresses, the intervertebral joints in the lumbar, thoracic, and sometimes even the cervical region undergo bony ankylosis.

 

Investigations.

The erythrocyte sedimentation rate is raised while the disease is active. In 90 per cent of cases the test for HLA B27 antigen is positive.

 

Diagnosis.

Ankylosing spondylitis has to be distinguished from other causes of back pain and sciatica. The marked limitation of spinal movement, reduced chest expansion, typical radiographic features, and raised erythrocyte sedimentation rate are diagnostic.

 

Larger Picture of Man (Size 87 Kb)

Patient with Longstanding ankylosing spondylitis
complicated by rigid flexion deformity.

Larger Picture of Man (Size 62KB)

After corrective
osteotomy in the lumber region

 

Course and complications.

The disease usually ceases to progress after ten or fifteen years, leaving permanent stiffness, the extent of which varies widely from case to case. Complications include fixed flexion deformity of the spine, intercurrent respiratory infections, and iridocyclitis, which in severe cases may lead to blindness.

 

Treatment.

Treatment is rather unsatisfactory, in that no method is known by which the disease process can be halted and spinal mobility preserved. In most cases the mainstay of treatment is a non-steroid anti-inflammatory agent usually see drugs page in the first instance. Steroid drugs are inappropriate except for ophthalmic complications. There may still be an occasional place for local radiotherapy for a particularly painful area, but this treatment is used much more cautiously now than it was in the past.


Apart from these measures, treatment should be directed towards preserving function. Activity rather than rest should be enjoined. Special exercises should be practised to make the most of such movement as remains. The patient should adopt the habit of sleeping flat upon his back on a firm mattress, with only a single pillow, to prevent increasing flexion deformity of the spine. If severe flexion deformity occurs through neglect of this precaution it may be corrected by wedge osteotomy of the spine in the lumbar region.

 Link to full Index