Health & Medical Neurological Conditions

Fibromyalgia: New Diagnostic Criteria

´╗┐Fibromyalgia: New Diagnostic Criteria

Hello, my name is Dr. Charles Argoff and I'm Professor of Neurology at Albany Medical College and Director of the Comprehensive Pain Program at Albany Medical Center in Albany, New York. Today, what I'd like to do is to introduce you to a 3-part series on fibromyalgia. This is a very common, chronic painful condition that affects between 1 and 6 million people in this country, depending on the surveys that you look at, and it is also seen worldwide.

In the first part of this presentation, I would like to focus on just what do we know, and how do we classify fibromyalgia? The current diagnostic criteria that the American College of Rheumatology (ACR) put forth over a decade ago include several main features. One, this is a chronic widespread, painful condition; pain is affecting many areas of the body, and it is associated with the demonstration of 11 out of 18 defined areas of the body, above and below the waist and on both sides of the body -- what are called tender points, no pun intended. Many people confuse tender point with trigger points. A trigger point is a term used in the evaluation of myofascial pain, which is a localized area of abnormality, not to be further discussed right now. A tender point is any area where palpation with 4 kg/cm of pressure or less is perceived as painful to the individual.

Ten or 15 years ago throughout the country, rheumatologists got together and examined patients in a very standardized fashion. These 18 tender points, again, above and below the waist and on both sides of the body, were highlighted as the areas that were most specific and sensitive when making the diagnosis of fibromyalgia. These criteria are being revised, and the reason that they're being revised is that for all of us who take care of patients with fibromyalgia we know that fibromyalgia syndrome or fibromyalgia is about more than just pain; it also includes fatigue, sleep disturbances, cognitive disturbances, and other comorbidities, and so the newer ACR criteria for diagnosis will include some of these non-pain-related features in helping to make the diagnosis. This will be [discussed] at another time.

The other point I'd like to make is that although we don't know what fibromyalgia is, that is not the same as saying that we don't know anything about fibromyalgia. This is very disturbing to me because people often confuse "not knowing something completely" with "not knowing anything." What have emerged are increasing amounts of data suggesting and pointing to the fact that fibromyalgia is clearly associated with a constant process known as central sensitization, and what this means in plain language is an augmented response to sensory processing through what we believe to be are primarily centrally enhanced features. So that, for example, a normally non-painful stimulus is augmented by the central nervous system to be experienced by the person with fibromyalgia as painful and that is the definition of a tender point. Normally, 4 kg/cm in a control (a person without fibromyalgia) does not cause pain. I use an algometer -- a pressure algometer -- when I examine patients with fibromyalgia to document this, but if you don't have this tool available in your practice, 4 kg/cm pressure is about the pressure you need to put on your thumb in order to blanch the skin at the top of your thumb. Use that as an example.

In other blogs, I will comment further on some of the scientific studies that emphasize the role of the central nervous system, but one thing that you should keep in mind: people with fibromyalgia, based on numerous studies, truly experience pain at a lower pain threshold. This point was confirmed during a functional MRI [magnetic resonance imaging] study done by Rich Graceley at the NIH [National Institutes of Health], who demonstrated that patients with fibromyalgia, blinded to what that they were experiencing, identified a stimulus as painful compared with controls. Each group had metabolic activity in very similar areas of the brain that are known to be associated with pain processing, and in fact more areas of the brain lit up, metabolically, in fibromyalgia patients. The importance of this is that even though a patient with fibromyalgia on average experienced pain at a much lower threshold than a control, that experience at a lower threshold still resulted in metabolic activity in areas of that person's brain that are associated with pain processing. That's a very important point to consider.

Thank you for listening, and I'm Dr. Charles Argoff.

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