Chronic Pain and Central Sensitization
One definition of pain is described as “a localized or generalized unpleasant bodily sensation or complex of sensations that cause mild to severe physical discomfort and emotional distress and typically results from bodily disorder (such as injury or disease) ” (1). Furthermore, pain can be classified in many different ways, one of which is to describe the duration of the symptoms. Acute pain is a type of pain that is present for less than 3 months and often times can last much less than that. Sub-acute pain is pain that has been present for at least 6 weeks but less than 3 months. Chronic pain is a type of pain that is present for over 3 months, sometimes extending far beyond that time frame (2). In addition, it is important to note that there are influences beyond physical stimuli or sensations that can relate to an individual's pain perception.
As healthcare systems have evolved, there is an important proposed model that is known as the biopsychosocial model. This model of understanding human health considers “biological, psychological, and social factors and their complex interactions in understanding health, illness, and health care delivery” (3). In relation to pain, this can suggest that factors outside of physical or biological elements have some role in the creation of pain perception or pain response. This can include things such as chronic stress, mental health or socioeconomic status as factors that might affect someone’s pain levels, pain perception, and symptom irritability.
Therefore, when examining the topic of chronic pain, symptoms can go much deeper than what we can see on the surface. Sometimes chronic pain can progress and develop to the point where actual changes occur on an anatomic level. In general, our pain perception (Nociception) relates to a noxious stimulus, an input that creates a pain response which is usually in line with the intensity, damage, or threat of harm caused by the stimulus (4). Usually, the painful sensation will resolve over time and will often fade away after the stimulus is removed and the body recovers. However, Nociception is “a protective process that helps prevent injury by generating both a reflex withdrawal from the stimulus and as a sensation so unpleasant that it results in complex behavioral strategies to avoid further contact” (4) with the stimulus. This sensitization to these pain-provoking stimuli can progress and eventually lead to a chronic pain syndrome noted as central sensitization.
Central sensitization relates to “changes in the central nervous system to the generation of abnormal pain sensitivity” that can include pain that “arises spontaneously, can be elicited by normally innocuous stimuli (allodynia), is exaggerated and prolonged in response to noxious stimuli (hyperalgesia), and spreads beyond the site of injury (secondary hyperalgesia) (4). In other words, if someone has central sensitization as a primary driver for their pain perception, they may experience pain that is higher in intensity, affects more areas than usual, and might show up in other areas of the body outside the site of injury, harm or pain. Additionally, central sensitization relates to an “abnormal state of responsiveness” (4) of the central nervous system meaning stimuli that are not typically painful might be interpreted as pain by the body.
Given this information, it might seem daunting to tackle treatment of this condition. However, physical therapy can serve as part of a comprehensive individualized program along with other members of the healthcare team. Physical therapy strategies for patients with central sensitization can include many of the following techniques (5).
In sum, pain can look different for many people, and sometimes this pain goes beyond musculoskeletal issues, instead being driven by the nervous system. Physical therapy management can be an important component of comprehensive care for patients suffering from chronic pain that may be debilitating
Citations
As healthcare systems have evolved, there is an important proposed model that is known as the biopsychosocial model. This model of understanding human health considers “biological, psychological, and social factors and their complex interactions in understanding health, illness, and health care delivery” (3). In relation to pain, this can suggest that factors outside of physical or biological elements have some role in the creation of pain perception or pain response. This can include things such as chronic stress, mental health or socioeconomic status as factors that might affect someone’s pain levels, pain perception, and symptom irritability.
Therefore, when examining the topic of chronic pain, symptoms can go much deeper than what we can see on the surface. Sometimes chronic pain can progress and develop to the point where actual changes occur on an anatomic level. In general, our pain perception (Nociception) relates to a noxious stimulus, an input that creates a pain response which is usually in line with the intensity, damage, or threat of harm caused by the stimulus (4). Usually, the painful sensation will resolve over time and will often fade away after the stimulus is removed and the body recovers. However, Nociception is “a protective process that helps prevent injury by generating both a reflex withdrawal from the stimulus and as a sensation so unpleasant that it results in complex behavioral strategies to avoid further contact” (4) with the stimulus. This sensitization to these pain-provoking stimuli can progress and eventually lead to a chronic pain syndrome noted as central sensitization.
Central sensitization relates to “changes in the central nervous system to the generation of abnormal pain sensitivity” that can include pain that “arises spontaneously, can be elicited by normally innocuous stimuli (allodynia), is exaggerated and prolonged in response to noxious stimuli (hyperalgesia), and spreads beyond the site of injury (secondary hyperalgesia) (4). In other words, if someone has central sensitization as a primary driver for their pain perception, they may experience pain that is higher in intensity, affects more areas than usual, and might show up in other areas of the body outside the site of injury, harm or pain. Additionally, central sensitization relates to an “abnormal state of responsiveness” (4) of the central nervous system meaning stimuli that are not typically painful might be interpreted as pain by the body.
Given this information, it might seem daunting to tackle treatment of this condition. However, physical therapy can serve as part of a comprehensive individualized program along with other members of the healthcare team. Physical therapy strategies for patients with central sensitization can include many of the following techniques (5).
- Central treatment approach working to retrain the brain and working on top-down mechanisms for the entire body as opposed to focusing on the painful area alone
- Education regarding pain science to correct pain beliefs, decrease rumination, decrease catastrophizing and work on coping strategies
- Intervention including graded activity, graded exercise and graded exposure to stimuli that were previously causing pain
- Education regarding sleep management, stress management and lifestyle factors that affect pain perception
- Individualized 1 on 1 care with a licensed physical therapist trained in pain neuroscience
In sum, pain can look different for many people, and sometimes this pain goes beyond musculoskeletal issues, instead being driven by the nervous system. Physical therapy management can be an important component of comprehensive care for patients suffering from chronic pain that may be debilitating
Citations
- https://www.merriam-webster.com/dictionary/pain
- https://link.springer.com/referenceworkentry/10.1007/978-3-642-28753-4_75#:~:text=Chronic%20pain%20is%20pain%20that,1997).
- https://www.urmc.rochester.edu/medialibraries/urmcmedia/education/md/documents/biopsychosocial-model-approach.pdf
- https://www.jpain.org/article/S1526-5900(09)00609-9/fulltext
- https://www.jospt.org/doi/10.2519/jospt.2016.0612