Chronic Pain Syndrome
What is chronic pain?
Pain normally subsides in, what is viewed as the normal healing time, a question of three to six months as tissues heal after an injury or illness. However, this is not always the case, and pain can continue even after the healing process is complete. Whenever pain continues after the normally expected period, this is referred to as chronic pain.
Chronic pain more often than not, is complex as it involves the nerves and nervous systems, also the central nervous system, i.e. the brain and spinal cord. With chronic pain the nerves continue to fire and signal the pain experience. Thus, chronic pain is a neurological condition in its own right, because of the changes in the nervous system unrelated to the original diagnosis or injury. If not managed well, chronic pain can be intense, ongoing, and debilitating, resulting in various degrees of disability.
Chronic pain more often than not, is complex as it involves the nerves and nervous systems, also the central nervous system, i.e. the brain and spinal cord. With chronic pain the nerves continue to fire and signal the pain experience. Thus, chronic pain is a neurological condition in its own right, because of the changes in the nervous system unrelated to the original diagnosis or injury. If not managed well, chronic pain can be intense, ongoing, and debilitating, resulting in various degrees of disability.
The chronic pain experience
Although everybody has different experiences of pain, the mechanisms at work in the body are similar for all.
Our Nervous System
Our nervous system consists of basically two types of nerves: sensory and motor.
In a nutshell, sensory nerves are generally responsible for communicating to the brain what is happening in the body. Motor nerves communicate to the body the appropriate action to take, i.e. the activation of our muscles, as well as the release of certain chemicals in the body. As the brain is interpreting these signals, taking action accordingly, most of this happens at a sub-conscious level, without our conscious awareness. Some research indicates that for a stress signal to flow from the Thalamus to the Amygdala (the stress centre in our brain), can take as little as one hundred millionth of a second! Thus the brain is already in a fight or flight mode long before we become aware of any threat that exists.
Our nerve cells are long and can reach from the most extreme part of the body to the spine. The nerves cells connect to other nerve cells via what is referred to as synaptical gaps, most of which are in the brain, but also in the spinal chord. For the signal to continue travelling to the brain, this is dependent upon the balance of chemicals at these synaptical gaps. As such, two types of nerve chemicals exist: excitatory, which result in the continuance of the signal to the brain, or inhibitory, which suppress the intensity of the signal. More excitatory chemicals are released to enable the brain to capture as much information as possible from the injury site to assess the damage. More inhibitory chemicals are released to suppress the intensity of the signal to ensure the completion of the task and a position of safety has been reached.
Looking at the pain experience, the brain is continually interpreting signals from the body, mostly on a sub-conscious level. Whenever the brain considers signals from a particular part of the body as unusual, it will send excitatory chemicals in order to obtain more information as to what is happening in that specific area in the body. E.g., if the brain receives signals it considers as unusual from our finger after cutting it with a knife, the brain will register pain, and the normal reaction is to pull away and taking some soothing action, e.g. sucking the finger or grabbing it with the other hand.
Thus it is the brain's interpretation of the incoming signals when pain should be experienced or not.
Our nervous system consists of basically two types of nerves: sensory and motor.
In a nutshell, sensory nerves are generally responsible for communicating to the brain what is happening in the body. Motor nerves communicate to the body the appropriate action to take, i.e. the activation of our muscles, as well as the release of certain chemicals in the body. As the brain is interpreting these signals, taking action accordingly, most of this happens at a sub-conscious level, without our conscious awareness. Some research indicates that for a stress signal to flow from the Thalamus to the Amygdala (the stress centre in our brain), can take as little as one hundred millionth of a second! Thus the brain is already in a fight or flight mode long before we become aware of any threat that exists.
Our nerve cells are long and can reach from the most extreme part of the body to the spine. The nerves cells connect to other nerve cells via what is referred to as synaptical gaps, most of which are in the brain, but also in the spinal chord. For the signal to continue travelling to the brain, this is dependent upon the balance of chemicals at these synaptical gaps. As such, two types of nerve chemicals exist: excitatory, which result in the continuance of the signal to the brain, or inhibitory, which suppress the intensity of the signal. More excitatory chemicals are released to enable the brain to capture as much information as possible from the injury site to assess the damage. More inhibitory chemicals are released to suppress the intensity of the signal to ensure the completion of the task and a position of safety has been reached.
Looking at the pain experience, the brain is continually interpreting signals from the body, mostly on a sub-conscious level. Whenever the brain considers signals from a particular part of the body as unusual, it will send excitatory chemicals in order to obtain more information as to what is happening in that specific area in the body. E.g., if the brain receives signals it considers as unusual from our finger after cutting it with a knife, the brain will register pain, and the normal reaction is to pull away and taking some soothing action, e.g. sucking the finger or grabbing it with the other hand.
Thus it is the brain's interpretation of the incoming signals when pain should be experienced or not.
The role of other systems and chemicals
The sympathetic/parasympathetic nervous system, the endocrine system and immune systems also have an influence on the experience of pain. These systems help to keep the body in balance. When the body is put under stress, causing an imbalance in the system, the amygdala activates the stress response system, resulting in increased production of corticotrophin releasing factor (CRF) by the hypothalamus, adrenocorticotrophin hormone (ACTH) by the pituitary gland, which jumps the brain-blood barrier, resulting in the release of noradrenalin, adrenalin, and cortisol. This compromises cortical blood flow as well as communication to frontal systems like the prefrontal cortex in the brain, increased blood flow to the rest of the brain and muscles, releasing energy for the muscles, increased heart rate and breathing, dilation of the pupils, and the suppression of the immune, digestive and reproductive systems. I.e., the body going into 'fight or flight' mode, ready for taking action.
The greater the amount of these excitatory chemicals that are released, the greater the pain experience. Also the longer the this state of 'fight or fight' continues, the more likely that changes will start to occur in the synaptical gaps and within the brain, which reduce the ability of inhibitory chemicals to work effectively, resulting in an increased pain awareness and a lowered pain tolerance. Thus, as the sensory system is changing, the brain is now more likely to consider any incoming signal - even normal sensations - from the vicinity of the initial injury or illness as dangerous and a threat. The longer these signals continue the more ingrained they become.
The sympathetic/parasympathetic nervous system, the endocrine system and immune systems also have an influence on the experience of pain. These systems help to keep the body in balance. When the body is put under stress, causing an imbalance in the system, the amygdala activates the stress response system, resulting in increased production of corticotrophin releasing factor (CRF) by the hypothalamus, adrenocorticotrophin hormone (ACTH) by the pituitary gland, which jumps the brain-blood barrier, resulting in the release of noradrenalin, adrenalin, and cortisol. This compromises cortical blood flow as well as communication to frontal systems like the prefrontal cortex in the brain, increased blood flow to the rest of the brain and muscles, releasing energy for the muscles, increased heart rate and breathing, dilation of the pupils, and the suppression of the immune, digestive and reproductive systems. I.e., the body going into 'fight or flight' mode, ready for taking action.
The greater the amount of these excitatory chemicals that are released, the greater the pain experience. Also the longer the this state of 'fight or fight' continues, the more likely that changes will start to occur in the synaptical gaps and within the brain, which reduce the ability of inhibitory chemicals to work effectively, resulting in an increased pain awareness and a lowered pain tolerance. Thus, as the sensory system is changing, the brain is now more likely to consider any incoming signal - even normal sensations - from the vicinity of the initial injury or illness as dangerous and a threat. The longer these signals continue the more ingrained they become.
Source: Australian Pain Management Association