Explaining Pain and Why Every Body Hurts ... Sometimes (Part 1)

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Why Do We Experience Pain?

Although pain is typically an uncomfortable and undesirable sensation, it’s also an essential element of our lives. Pain let’s us know when we should avoid something that can cause us physical harm, like touching a hot stove; it notifies us when the body is experiencing harm.

This aligns with the theory that there are pain receptors (nerve endings called nociceptors) throughout our body and when they come into contact with a stimuli (for example a sharp object, a hot surface, or chemicals found after inflammation) that can cause damage, a signal is sent through the spinal cord and to the brain, manifesting as pain. From here, a response to remove the body from harm is then sent back by the brain to the stimulated area.

Although, this may appear as an elegant solution by the brain for preventing harm, recent development in understanding the processes of pain has shown that this only scratches the surface, and that pain is a complex process that involves physical, psychological, emotional and social factors. The complexity of pain is particularly evident when dealing with chronic pain.

The Complexity and Impact of Chronic Pain

Chronic Pain is defined as pain that lasts beyond the expected recovery time (typically more than 3 months) for a certain injury, surgery or other condition. Common conditions where chronic pain is experienced include diabetes, osteperosis, migraines, and perhaps most prevalently, back pain.

Chronic pain can last from a few months to years on end, despite any injury having healed and there no longer being any physical harm being caused. 1 in 5 Australians live with chronic pain and as one of the leading causes of disability, chronic pain contributes an economic cost of $34.4 billion per annum.

Chronic pain commonly develops subsequent to untreated or poorly treated acute injuries, although the direct cause of chronic pain can be difficult to isolate, as other factors such as beliefs about pain, environmental and psychological factors all contribute. This makes pain, and the experience of pain extremely subjective, further supporting its complexity to manage.

Understanding Chronic Pain – The Mature Organism Model

Many theories have been proposed to assist in understanding pain mechanisms, although there is little doubt that there is more to be revealed in the future. A proposed model by Louis Gifford known as the Mature Organism Model (below) outlines the relationship between the brain, the body’s tissue and the external environment in eliciting a pain response.

In Gifford’s model, the brain is seen as a ‘scrutinising centre’. This means the brain assesses the ‘signal’ provided from the body’s tissue. This modulation by the brain is influenced by environmental factors, pain beliefs and past experiences. This is where fear of pain or further damage can sensitise and increase the perception of pain. After modulating the pain, the brain then decides on an action or ‘output’ which can be physiological or behavioural.

Looking at a common example in chronic back pain, the model suggests the process may begin with an irritation a joint in the lower back whereby the pain receptors in the back sense the presence of inflammatory chemicals and send the impulse to the brain via the spinal cord. The brain modulates this input and determines a response based on experiences and environmental factors, for example: one may be excessively fearful and anxious about requiring surgery for back pain, the brain then sends an output, for example, tightening the back muscles to try and protect the irritated area. This tightening can restrict range of movement and subsequently hinder participation in physical and social activities. This can quickly manifest into a vicious cycle whereby the lack of social participation can affect one's psychological state, causing them to be more anxious or depressed about their situation, further sensitising the brain's modulating process.

Managing Chronic Pain

Recent evidence suggests the best strategies for managing chronic pain that we currently have, is a multi-disciplinary approach to treatment as early as possible, using evidence-based practice as well as self-management strategies. This commonly involves management with a doctor, psychologist (or psychiatrist) and physiotherapist. Combining these professions in a tailored approach to management to identify potential contributors to chronicity, maintain physical activity and participation levels and provide education regarding strategies to maintain independence and self-manage chronic pain.

Stay tuned for our next post where we discuss the management strategies for chronic pain and the relationship between chronic pain and mental health.

If you experience muscular or joint-related pain, or if you have questions or would like to know more, do not hesitate to CONTACT US

References

1. https://pdfs.semanticscholar.org/8505/65db9ff6a04a1b370d72df85338f32b4b468.pdf

2. https://www.painaustralia.org.au/about-pain/what-is-chronic-pain

3. https://www.painaustralia.org.au/about-pain/painful-facts

4. http://painaustralia.staging3.webforcefive.com.au/static/uploads/files/painaust-factsheet2-wfdahrmggvwp.pdf

5. https://pdfs.semanticscholar.org/cc26/6f3ea81c0936d14507686fc3c87b7069c19d.pdf

6. https://www.painaustralia.org.au/static/uploads/files/national-pain-strategy-2011-exec-summary-with-stakeholders-wftfjtpbdaij.pdf

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