Physiological Mechanisms of Chronic Pain

The causes and treatment of chronic pain are worthy of continued research. This is largely due to the wide variety of contributing factors, in both the individual and in the external factors that come to bear upon that individual. Treatment methods may then be appropriately selected based on each individual case.

 

Treatment approaches vary widely, and it is difficult to weigh the relative costs and effectiveness of various treatments due to the fact that it is hard to accurately assess and quantify pain. One is forced to rely on the subjective reports of the patients. Nevertheless, some general conclusions can be drawn. Regardless of the inital injury, there are physiological processes common to almost all chronic pain.

 

It is worth studying reflex arcs and their role in chronic pain. Fundamentally, reflex arcs can be understood as a normal, healthy responses to injury that carry the potential to cause problems over time.

 

The healthy functioning of reflex arcs may be understood by the example of burning one's hands while picking up a hot coffee mug. In this example, several things occur. Upon touching the hot cup, nerves transmit pain signals to the spine, the hand jerks away, local blood flow and sensitivity increases, and adrenaline is released into the bloodstream.

 

 This set of reflex responses can have an undesirable effect. Constant, low-grade pain causes persistent firing of pain signals, causing tight muscles, locally increased sensitivity and circulation, and the accompanying low-grade release of adrenaline. Many of us are familiar with this effect as the result of too much strenuous exercise. In most cases, we only take a short while to heal.

 

In the case of chronic pain, this normally healthy set of responses blossoms into what may be termed a vicious pathological reflex arc. In this condition, the tight muscles, locally increased sensitivity and blood flow, and low-grade release of adrenaline advance to the point where they themselves cause pain. This triggers a cascade of pain responses which doesn't readily resolve itself.

 

The question then becomes: how can this cycle be broken? If responded to early enough in the process, positive results can be realized through correction of the causal factors. Later on, direct intervention may be required.