We used to equate the intensity of our pain with the intensity of damage to our tissues. Now we know this is not true. We can have severe pain and no injury. We can have significant injury and feel minimal pain.
Input from the body goes thru the spinal cord to the brain à multiple parts of the brain meet to determine if you are safe or if there is perceived threat à if meeting determines there is threat then you feel pain. (if no threat – no pain)
This input can be internal or external. Examples include:
· Pressure or touch
· Changes in stress hormone levels
· Immune reaction to a cold or acute illness
Acute pain has the same sequence listed above. Input from body à meeting in the brain to determine if there is risk for injury or harm à you feel a proportionate intensity of pain based upon potential for injury. Even with acute pain, our emotions, memories, and thoughts about pain all play a role in what we experience. But with acute pain there are not the changes in the nervous system (i.e. upregulation and increased sensitivity to internal and external input) that are present with chronic pain. In theory, acute pain will last an appropriate duration and intensity as the tissues heal. Fractures will take longer to heal and be more painful than say a small sprain.
Studies show that 1 in 4 people will experience pain that lasts beyond the expected healing time for the injured tissues. This is related to an increased sensitivity to internal and external inputs. Scientists have not been able to identify what causes this to happen but it has been determined that stress levels, coping mechanisms, sleep quality, nutrition, movement / exercise, increased flight or fight system activation all play a role in the ongoing sensitivity of the nervous system and therefore ongoing chronic pain symptoms.
I mentioned this sensitive nervous system. Sensitive can be a challenging word to hear. Upregulated, elevated, increased response to changes are other ways to describe what happens to the nervous system. Think of it like an alarm on your home. You want that alarm to go off if a thief is trying to get into your home (we want to feel pain to warn us that something may harm us). But we do not want that alarm going off when the wind is blowing a leaf at the end of the drive way (we don’t want to feel pain if there is not an eminent potential for injury or harm).
There is no blood work or diagnostic test to determine if this is happening to you. We know based upon your story and your clinical presentation. If you used to be able to do more in your daily routine but now you are significantly limited due to pain and fatigue, this indicates you are dealing with increased sensitivity of the nervous system. Other indications include: increased sensitivity to light touch, the weight of a blanket on your legs or other pressure which is not causing any harm. Potentially if you are on certain medications, such as Gabapentin, we know that your doctor is trying to calm your nervous system down.
Chronic illnesses or degenerative changes that are associated with pain overlap with these concepts as well. If you have arthritis or Fibromyalgia for example, you may experience chronic pain. If so, the elevated nervous system or sensitive alarm system is the same as if you had a specific injury that healed but is still painful. The nervous system responds to internal and external changes at a greater intensity including cold weather, stress, weather changes, and immune responses.
I am just sharing the tip of the ice berg of the changes that happen in the nervous system when someone is experiencing chronic pain. But hopefully this at least gives you a better understanding of how pain works and an introduction into what happens with chronic pain. Next time we will review some ways to help with chronic pain management.