Inflammatory vs. Mechanical Back Pain

According to the Mayo Clinic, "Back pain is a common complaint. Most people in the United States will experience low back pain at least once during their lives. Back pain is one of the most common reasons people go to the doctor or miss work."

Back pain can have many causes but chronic lower back pain has been shown in a recent study to be associated with spondyloarthritis at a rate that is "strikingly high".

When diagnosing ankylosing spondylitis or related disease where back pain is present, it is important to distinguish the underlying cause. Specifically, is the back pain inflammatory in nature or mechanical?

A segment from Dr. Michael Weisman's Spondylitis Educational Seminar presentation given in Denver, CO in 2008 describes the differences between mechanical and inflammatory back pain. Inflammatory back pain is the variety associated with ankylosing spondylitis and other spondyloarthritides.

When determining if the back pain is inflammatory in nature and related to a disease such as ankylosing spondylitis, the following is often taken into account:

  • Onset of pain is usually under 35 years of age and is insidious
  • Pain persists for more than three months (i.e., it is chronic)
  • The back pain and stiffness worsen with immobility, especially at night and early morning
  • The back pain and stiffness tend to ease with physical activity and exercise
  • NSAIDs are very effective in relieving pain and stiffness in most patients

Note that inflammatory back pain by itself should not be used to diagnose ankylosing spondylitis. Instead it is a very important characteristic which the physician considers along with other findings such as x-ray or MRI evidence of sacroiliitis, the detection of the gene marker HLA B27, or the history of another related physical finding such as Iritis.

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