One of the most irritating aspects of any injury is the accompanying inflammation and swelling that occurs. From a sprained and swollen ankle to a painful bump on the arm after an insect bite, inflamed tissue is one of the most common occurrences in any injury. Although everyone experiences inflammation at one point or another, few people really understand what is going on with their body when a certain part is swollen and tender, and why the pain can be so bad after such an injury.
In fact, the pain that comes along with an injury can be more agonizing than the injury itself. A simple twist or too much rounding of the back can cause the muscles to feel painful for days or weeks. The inflammation itself is a response to the tissue damage, whether it is from trauma related to pressure, temperature, or chemical reactions in the body. But one of the reactions that occur along with inflammation is an increased sensitization of the nerves and neurons in the area of the injury. The pain sensors also become more highly activated with tissue damage.
In the short term, though, inflammation is good for the body after tissue damage has occurred. The swelling and tenderness are signs of increased circulation and blood flow to the injured area. Without this increase in circulation, it could take much longer to heal from an injury, if full healing would be possible at all. Thus, the body’s inflammatory response right after tissue damage that lasts for days or weeks is an attempt to protect the body part that has sustained the damage.
All of the tissues of the body can become inflamed and swell up due to increased circulation. And all of the tissues of the body can heal. We all know that cuts and scrapes on the skin will heal after a period of bleeding and scabbing. Torn muscles and sprained tendons heal in a matter of weeks or months after the initial swelling. Even ligaments can heal, even though they may take much longer — months or even years in some instances. And everyone knows someone who has had a broken bone that has been splinted, set, and healed after being immobilized for some time.
Changes to the nervous system after an injury, however, may be longer lasting, even permanent. In some cases, the body may become more highly sensitive after sustaining damage, as the brain and nerves scan the injured area for more signs of danger, even long after the injury has healed. In some unfortunately circumstances, these changes to the nerves and brain may lead to chronic pain syndromes. This indicates that the nervous system is sending pain messages to certain tissues in an attempt to protect against future damage, regardless of whether or not the tissues are actually in danger.
Thus, inflammation is a natural response to injury and tissue damage, and without it, we would have a very difficult time recovering from hurting ourselves. Additional changes to the area that has been hurt include increased sensitization of the nerves in the area, as the brain tries to protect us against further harm. But when these changes become permanent and the nerves keep sending pain messages to already healed tissue, chronic pain can develop as a result of the increasingly sensitized nervous system.