The Concept of Central Sensitization

Fibromyalgia presents itself as [hyperalgesia], or an increased response to a stimulus that is normally painful. In other words, if I press deeply into any one of these tender points and aggressively manipulate the tissues, I would expect a painful response. What is unusual in fibromyalgia is that these tender points are much more pronounced and respond to even minimal amounts of pressure. In other words, there is a decreased threshold to pain with simple "bumps" and movements resulting in a painful response. The Copenhagen Fibromyalgia Symposium defined fibromyalgia as a patient that must have at least 11 of 18 specified tender points. They must be present in all four quadrants of the body and when the patient has met this criteria, they have "fibromyalgia". However, two types of hyperalgesia have been described. Primary hyperalgesia develops in an area where injury to tissues has occurred and secondary hyperalgesia may be found in undamaged tissue. Both of these clearly respond differently to both mechanical and thermal stimuli. This is one of the reasons you will find that I disagree many times with the classic definitions and diagnosis. Science evolves our understanding of the interrelationships of the Fibro 5.

Muscle pain receptors are also sensitized extensively by chemicals released around them that activate pain mechanisms. Many practitioners believe that decreased blood flow and lack of oxygen increase the pain in these muscle tissues. It is possible that these chemicals are released due to this decreased blood flow and [hypoxia] but very little evidence supports this.

As this web page develops, the concept of central sensitization will be widely explored. The greatest promise of finding help for those suffering from fibromyalgia is identifying the sustaining mechanisms that continue the unrelenting pain. Tender points might be useful in helping us diagnose fibromyalgia but tender points are present in those that do not have the disease. Also of note, common symptoms of the Fibro 5 cannot be diminished. For instance, chronic fatigue, sleep interruption, depravation, and depression (to name a few) overlap physical findings and are common in the Fibro 5. The process of central sensitization explains much of this phenomena.

Myofascial Pain Syndrome is described as a regional pain syndrome with specific zones of deep pain defined as a "trigger point". Trevell and Simons (1983) describe their interpretation of trigger points in great detail. We will critically explore this work by Trevell and Simons and relate it to recent scientific understanding of histiologic, biochemical and electro-physiologic mechanisms that might explain these "trigger points".

Better understanding of fibromyalgia and Myofascial Pain Syndrome is extraordinarily important for the "The Fibro 5" to better convey their symptoms to friends, family and caregivers.