Why Pain is Stubborn

A summary  of a recent talk by  a neurophysiologist (Mike Patterson PhD)  helps explain what happens in chronic pain.
This was given at an October 2007 conference at the University of Wisconsin.

1. Changes in nerve endings themselves.  Nerves that used to be just mechanical (ie., pressure or position sense, telling us what position our body parts are in) become pain transmitting nerve endings instead.  This means that just holding an arm up or our body in a certain position will stimulate pain fibers.

2. Changes in muscles.   When ligaments and tendons are abnormal, muscles that are connected become sources of pain too.  Measuring painful spots in muscle reveals  elevation of many of the pain transmitters or substances know to associate with more pain such as bradykinin, serotonin, substance P, CGRP, TNFalpha, interleukins 1b, 6 and 8.

3.  Spinal cord changes.  These changes are like a football team that loses half its defensive line and cannot protect itself from pain.  With chronic pain over time the "defensive" neves that block pain just drop out.  This means that pain that is not normally severe can be severe because it is not dampened down by these pain blocking nerve fibers.  Mild pain can stimulate nerves in the spinal cord that transmit bad pain to the brain.   Note that this pain is bad, so it is absolutely real, but it can be caused without a dangerous or severe cause.  Note also that taking chronic narcotics appears to also decrease the number and effectiveness of pain blocking cells in the spinal cord. 

4.   Brain changes.  Areas in the brain that process pain can become active on their own, causing the brain to appreciate pain long after the source of pain has been improved.

5.  Nerve changes from taking narcotics.  This is called opiate induced hyperalgesia. Wikipedia has a summary of this. This issue is quite important and explains why those already on regular narcotics do not do as well.

 

Why do I mention all this?
(1) To explain why chronic pain responds with more difficulty.
(2) To indicate why just living with chronic pain and postponing treatment for long periods should be avoided as possible.

A great deal of research is going on about these unfavorable changes but this is a very complex area.
The reader should take hope:  this research is vital to achieve true cure in the most difficult cases of pain.
It is important to know that pain control is not a simple as just finding weak ligaments and tendons and strengthening them.

Important Note:
It is now increasingly thought that stubborn pain is due to nerves being
compressed as they penetrate through linings in our body called fascia.
Please see this handout for more information.