BONE & JOINT DISORDERS (ARTHRITIS)
ANKYLOSING SPONDYLITIS – INVESTIGATIONS
Laboratory investigations include :
- Blood test
- ESR (erythrocyte sedimentation rate) is usually raised due to infection.
- C-reactive protein is usually raised due to inflammation
- Serology test
- For rheumatoid factor & anti nuclear antibody : Both the tests are negative in Ankylosing spondylitis.
- HLA-B27 gene : This is positive in 90% of cases of Ankylosing spondylitis.
- X-Ray shows
- Signs of sacroilitis (inflammation of hip joint) in lower part of joints with irregularity and marginal sclerosis, finally progressing to fusion.
- Squaring of vertebras in lumbar spine ( due to fusion of anterior and lateral ligaments, syndesmophytes formation, erosion and sclerosis of anterior corners of vertebra)giving an appearance of ‘bamboo spine’ or ‘rail road track’.
- Signs of osteoporosis may be seen in later stages.
- ECG, Lung function test and Renal function test : In case of involvement of heart, lung or kidney respectively.