What is Pain?
Pain is an unpleasant complex experience that occurs in response to a potential threat to our body’s tissues. No one really wants to have pain and if you do get pain you typically want to get rid of if ASAP. What we need to remember is that pain is normal and necessary to our survival as it is our body’s alarm system. The alarm system is there to help bring our attention to potential threats and to change our behaviour to avoid the threats if necessary.
Everyone experiences pain differently. The way we experience pain depends on many factors such as the following: the severity of tissue injury, our emotional responses, previous experiences with pain, cultural experiences, the social and physical environment, our sensory inputs from receptors in our body, beliefs and knowledge about pain and our expectations about the consequences of pain.
For example: A person who is a major league soccer player that fractures their ankle will feel the pain very differently compared to a 65 year old person who is relatively sedentary because the soccer player may feel anxious about how is he going to make money if he can’t play soccer, whereas the 65 year old who generally is not very active will not have much change in their day.
How Do We Experience Pain?
When your body is injured in some way whether it be from stubbing your toe, repetitive use of you shoulder or appendicitis, the receptors and nerves in your body send this information to your brain and it is your brain that decides whether or not you feel pain. These receptors in your body are called nociceptors and they respond to thermal, chemical or mechanical changes on the tissues. For example, when you place your hand on a hot stove top the receptors in your fingers and hand sense that the temperature has changed. They then send messages to your brain about the temperature change and your brain decides if this change in temperature is a threat and if you should feel pain to make you take your hand away from the potential threat of a burn.
The signals from the nociceptors do not create pain. It is the brain decides that receives the signals from the nociceptors and other information such as your memories of pain, your beliefs about pain, your emotions at the time of the signal, your expectations and the information about the environment and uses all the information to decide whether or not there is a threat of damage and whether we should feel pain. The brain may decide that a nociception signal is not important and that we do not need to feel pain, so we ignore it. An example of this is when we are sitting in a chair the receptors in our bottom notice the change in pressure an send this signal to the brain. The brain then takes the information from the signal, and the environment and decides that sitting in the chair is not harmful so therefore we do not feel pain.
An analogy that can be helpful understand pain is to think of pain like a ship that is sailing in the ocean. The receptors are the lookouts on the ship, and they notice lights in the distance (these are the potential danger signals). The brain is the captain of the ship and makes all the decisions about how to sail.
The lookouts notice lights in the distance and tell the captain about them. The captain then considers his memories about these waters and takes in information about the environment. Maybe the captain knows these waters well and knows that these waters are safe and pirate free. He would then decide that the information was good to know but not very important, he may tell the crew members not to worry about it and they continue to sail as normal. This is like the when you sit in the chair and the brain decides that it is not a threat, so you continue sitting as normal without pain.
But if the captain is concerned by the information because he has never sailed these waters before and thinks that the lights may be pirates coming to rob the ship, he may tell the other crew members to stay on high alert. This is like when you place your hand on the hot burner and the brain creates a pain experience to make sure you are aware of the potential threat. He may even change the way he was sailing to avoid the pirates. This is like when pull your hand away from the burner because of the pain to avoid the threat of a burn.
Types of Pain
Pain can be either acute or chronic.
We tend to consider acute pain as pain that has a “mechanism of injury” such as a fall, motor vehicle accident, slamming your finger in a door etc. Acute pain typically is short lived, most times is not present past 3 months (BUT not always) and usually follows the stages of tissue healing (which are outlined in the picture below).
Chronic pain is when the pain is occurring for a longer period of time. It is often disproportionate to the stages of tissue healing and may or may not have a mechanism of injury that explains why the pain is there. Chronic pain can be very complex and is not fully understood. Chronic pain is usually pain that is present past the usual tissue healing process. Meaning that the tissues have likely healed, and no more damage is likely being done. But a reason we may still get pain is because our tissues have become more sensitized. If you think of the body as a ship again. Sometimes even through the ship has long since cleared the pirate-infested waters the captain and the crew remain hypervigilant to be sure they are safe. This means that now, even normal and helpful signals such as lighthouses, and ship horns may be perceived as threats. This can be the same as if we are in pain for a long time the entire system including the nociceptors and the brain become hypersensitive to all the information that even the normal signals that the brain usually ignores will be considered threats and you feel pain even though there is no tissue damage occurring.
Management of Pain
Management of pain can be complex because of all the factors that contribute to pain. Therefore, management of pain may have to be individualized. Pain management can include many things such as resting the area of injury, use of modalities such as ice or heat, education by a health professional about exercises, work or activity modifications, education about what to expect, healing duration as well as management strategies of stress or anxiety.