Over 100 million people in the United States suffer from chronic pain. This pain often limits their daily function and participation in the activities they love to do. So have you ever wondered what causes pain and why it can persist for years? This all starts with a basic understanding of what causes pain.
TYPICAL PAIN RESPONSE
The majority of people, both patients and medical providers, have learned pain to be caused by an event which produces damage in the tissues of our body. This is what causes us to yell “ouch, that hurts!” This reaction is a good thing and is what keeps us alive and well. There are 3 ways you can stimulate these “pain” receptors. Mechanical (ie. a paper cut), thermal (cold or hot) and chemical (ie. inflammation). After a certain period of time, tissues heal and the pain goes away. Think about a time you gave yourself a paper cut or scrapped your knee. It hurt when it happened and was then sore to touch for a few days. Typically it is not painful to touch your hand or knee so why does it stay sore for those few days after the initial incident? This is because the body increased sensitivity to that area to prevent further damage while it healed itself. This is typically caused by inflammation; a normal and necessary process of healing. Once it felt it was healed, it turned down the “volume,” or sensitivity, in that area and returned to its normal state. You can again touch your knee without causing yourself pain. This process is demonstrated by Figure 1 below. This prevents that spot where you scrapped your knee or got the paper cut from being painful the rest of your life.
CHRONIC PAIN RESPONSE (CENTRAL SENSITIZATION)
So why does pain persist for so many? Studies in the past 20 years have revealed pain is more complicated than just an event resulting in tissue damage, telling your brain ouch that hurts. We now understand that pain is a protective mechanism which is produced by the brain. We now see pain as an output rather than an input from damaged tissues. One of those 3 receptors described earlier are stimulated, causing a danger signal to be sent to the brain. This signal is then combined with various factors (see figure 2 below) as well as past experiences to produce the common term we know as pain.
This combination of events is referred to as the pain neuromatrix. This can result in prolonged inflammation and a persistent output of pain signals from the brain. There are many mechanisms which can produce this heightened pain response which results in a term called central sensitization. This means the nervous system which was once able to tolerate a non-painful sensation such as pressure on the skin or bending over to pick up an object, becomes oversensitive to this sensation and results in these non-painful sensations to become painful. This is demonstrated by Figure 3 below.
Here at Aquacare we can provide further education in these pain mechanisms and what is causing your pain while assisting in your return to function!