There is no specific test to diagnose ankylosing spondylitis, but imaging by X-ray and MRI may show evidence of inflammation of the sacroiliac joint between the sacrum (the triangular bone at the lowest part of the back) and the ilium (the bone felt on the upper part of the hip). Some symptoms may include:
Inflammatory back pain (gradual in onset, lasting over three months, with stiffness and pain that is worse in the morning and improved with movement)
Reduced mobility of the spine
Is linked with morning stiffness that usually
lasts for more than one hour
Improves with exercise
Your doctor will want to know whether you have any family
members who have ankylosing spondylitis or a related joint disease. Many people
with ankylosing spondylitis have a family member with the same condition. He or
she may also ask whether you have had ongoing diarrhea, abdominal (belly) pain,
multiple infections of the
cervix (in women) or
urethra (more common in men),
psoriasis, or inflammation of the eye chamber (uveitis). These could be clues to having a condition
other than ankylosing spondylitis.
You will have a physical exam
to see how stiff your back is and whether you can expand your chest normally.
Your doctor will also look for tender areas, especially over the points of the
spine, the pelvis, the areas where your ribs join your breastbone, and your
heels. You may experience chest pain and stiffness with ankylosing
Tests related to ankylosing spondylitis
X-rays of the
spine and pelvis to check for bone changes (bony erosions, fusion, or
calcification of the spine and
sacroiliac joints). Certain changes in the sacroiliac
joint confirm the diagnosis of ankylosing spondylitis. But those changes can
take several years to develop enough to show on X-ray.
CT scan are more sensitive than X-ray. If no changes
to the sacroiliac joints show on the X-ray but your doctor still suspects
ankylosing spondylitis, an MRI or CT scan may allow an earlier diagnosis.
Ultrasound is being studied as a way to diagnose
ankylosing spondylitis earlier.
genetic test, which may be done
to determine the presence of a
gene (HLA-B27) that is often linked with
ankylosing spondylitis. Many people who have the HLA-B27 gene will not develop
ankylosing spondylitis, so having this test will not confirm whether you have
the condition. But the test results can be helpful if your symptoms and
physical exam have not clearly pointed to a diagnosis.