When it comes to managing chronic pain, have physicians been looking in the wrong places? Physical findings in peripheral tissues rarely match up with patients’ reports of pain, or vice versa. Yet, clinicians typically examine only the area where the patient reports the pain, rather than looking at the whole body and considering that the patient’s perception of persistent pain may have a more central origin, according to pain expert Dr. Daniel J. Clauw.
“There is no chronic pain state where degree of damage or inflammation in the periphery correlates well with level of pain. Yet, the diagnostic algorithms or paradigms that everyone uses for treating chronic pain still assume that all pain is nociceptive. What we see in the peripheral tissues is not necessarily what our patients are experiencing,” Dr. Clauw said at last week at a 2-day scientific workshop on pain and musculoskeletal disorders, sponsored by the University of Michigan and held on the Bethesda, Md., campus of the National Institutes of Health.
That narrow focus has led many medical professionals to assume that when there is a disparity between peripheral findings and pain, the pain must be caused primarily by psychological factors. A prime example is fibromyalgia, still a somewhat controversial diagnosis. But as the first chronic pain syndrome identified as NOT being caused by peripheral inflammation or damage, fibromyalgia is “a metaphor for the centrality of chronic pain,” Dr. Clauw said.
So what should clinicians do differently? First, look beyond the immediate area the patient is complaining about. Has the patient had pain in other parts of the body? Experience frequent headaches? Have irritable bowel? Previous chronic neck pain, and now pain in the hip? “To me as a pain researcher, this is a blinking neon light that the person has a problem with pain processing. It may be that the particular symptom they’re coming in with is due to increased volume control setting rather than a pathologic problem in that part of the body,” Dr. Clauw told me.
And treatment? Ensuring adequate exercise and sleep and reducing stress are important yet underemphasized. Cognitive behavior therapy also has been shown to help. Pharmacologic therapy that acts centrally, rather than peripherally, may also be effective. The antidepressant duloxetine (Cymbalta), for example, is a serotonin/norepinephrine reuptake inhibitor that has been recently approved to treat osteoarthritis of the hip and low back pain, in addition to fibromyalgia and diabetic peripheral nerve pain.
A major challenge, Dr. Clauw believes, might be in getting clinicians to change their approach to pain. “It takes a long time for people trained in one way of thinking to think differently. This isn’t just a new drug or a new device. It’s a major paradigm shift.”
-Miriam E. Tucker (@MiriamETucker on Twitter)