The Physiology of Stress Illness (1)

Stress Illness consists of medically unexplained physical symptoms that improve in response to diagnosis and treatment of psychosocial stresses.  Since these symptoms are not imaginary, they are undoubtedly associated with one or more underlying abnormalities in physiology.  These are poorly understood but a recent article* reviews the latest research as it applies to fibromyalgia (FM) with likely relevance to many forms of Stress Illness.

Studies have revealed that people with FM experience pain differently.  Their peripheral nerves are more sensitive to pain, their brain images during pain are different and they report pain in response to milder stimuli than people without FM.  Here are some research results that support and elaborate on these statements, presented with minimal jargon.

1. As a stimulus (pressure on the thumb) was gradually increased from barely noticeable to painful, pain centers in the brain became active in FM patients sooner (ie with less pressure) than in healthy people.

2. When thumb pressure was set at a level that was painful for FM patients but not painful for healthy people, areas of the brain that block pain signals were active in the healthy people but not active in FM patients.  That is why the healthy people did not experience the pressure as pain.

3. Even when in no pain, the pain centers in the brain in FM patients were more active than the same centers in healthy people.

4. A normal phenomenon is that after an initial pain, subsequent pain in the same location feels worse.  This pain amplification, which results from activity in the spinal cord, is exaggerated in FM patients compared to healthy people.

More to come in the next post on this subject.

* Abeles et al.  The Pathophysiology of Fibromyalgia. Ann Intern Med. 2007; 146:726-734.

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