Identifying Ankylosing Spondyloarthritis
Allan Gibofsky, MD: With regard to ankylosing spondylitis, this is primarily a disease of young men. The diagnosis is made, sadly in many instances, later than it could be because of the fact that the pain that people are experiencing is often attributed to other factors. The pain is attributed to sports activities. The pain is attributed to helping your buddy move his apartment. The pain may be attributed to too much recreational dancing on a Saturday night, or series of Saturday nights, as well as other activities that may follow from them. But what that means is that since young men are relatively reluctant to seek medical attention for lower back pain, the back pain progresses. And not until someone may remark “You’re walking funny” or “You look a little bit shorter than you used to be” do we make the diagnosis. Often, we may see associated features, such as an enthesopathy, even in patients with ankylosing spondylitis. The x-ray that’s taken may reveal what’s referred to as the “bamboo spine appearance,” where there is fusion of the spine over the discs to look like bamboo. In addition, there may be what’s called “bridging syndesmophytes,” meaning that there are spicules of bone extending upward from the lower spinal process, downward from the upper spinal process, until they meet and form a bridge. And these tend to be characteristic in ankylosing spondylitis.
Another feature in the evaluation of a young man or woman with ankylosing spondylitis is the genetic marker HLA-B27, which is prevalent in these individuals. The prevalence is a function of their racial background, but virtually all races have shown an increase of HLA-B27 in patients with ankylosing spondylitis. In addition, we will do a panel of serologies (or they may have been done as part of an arthritis panel by the referring physician) and we find that the rheumatoid factor is negative, once again confirming that we are dealing with a seronegative spondyloarthropathy of which ankylosing spondylitis may be the cause.
The presentation of pain is variable. Some patients complain of pain at night with improvement upon walking around. Some patients complain of pain during the day with relief at night. So, while there are guides as to pain patterns for ankylosing spondylitis that can occur in the lower back and sacroiliac joints and hips, these are not uniform. We have also seen that ankylosing spondylitis, or a form of it, may actually begin in the neck and progress downward rather than the most typical form, which begins in the lower back and progresses upward. So, the physician has to be alert that not only low back pain may herald the onset of ankylosing spondylitis, but chronic and intermittent neck pain may be one of the clinical presentations of ankylosing spondylitis as well.
Again, a family history may be important. Because there is such a strong genetic predisposition, if a first-degree relative, particularly a male first-degree relative, has ankylosing spondylitis, the individual offspring or sibling with HLA-B27 is at significant increased risk, such that HLA-B27 is used as one of the classification markers in establishing the diagnosis. Patients with ankylosing spondylitis may also have eye disease and present with noninfectious inflammation of the eye—uveitis. And these, taken together, may allow for an inference of the diagnosis.
Finally, here is one of the conditions where we do have a little bit more information about genetic triggers. We know that certain bacteria that affect the gut can also result in a reactive arthritis—that is, you’re reacting to the bacterial infection and developing a form of axial disease or disease in the spine. Certain Gram-negative bacteria have been particularly implicated in the pathogenesis of what turns out to be ankylosing spondylitis in the HLA-B27—positive individual.
Transcript edited for clarity.
