Understanding how pain works is essential for your recovery

What do you think of when you hear the word pain?

According to the International Association for the Study of Pain, pain is defined as ‘an unpleasant sensory or emotional experience associated with actual or potential tissue damage’.

While unpleasant, pain is necessary for our well-being and survival, as it is how we detect harmful stimuli within our ever-changing environments - allowing us to react and adapt.

Pain can become unhelpful (i.e. pathological) when it no longer serves as an acute warning system and instead becomes chronic and debilitating.

This is what leads many people to seek help to resolve pain.

The mechanisms of pain and how the body responds to them

To understand the different solutions available to manage or resolve pain, it’s helpful to first understand the mechanisms by which pain is communicated.

These mechanisms can be categorised as nociceptive, neuropathic and dysfunctional.

Pain generation is a complex experience involving the brain, spinal cord and all the nerves that extend from there to innervate our body (peripheral nerves).

Nociceptive pain

Nociceptors are sensory receptors that are activated by harmful stimuli that damage or threaten the body’s integrity.

Nociceptive pain is experienced at the site of injury - these pain receptors detect mechanical, thermal or chemical stimuli at an abnormal level.

The chemicals that activate pain receptors are typically those produced by damaged tissue and can remain present for the entirety of a healing process.

Following the detection of such stimuli, a signal is sent along a peripheral nerve toward the spinal cord.

Within the spinal cord, chemical messengers (neurotransmitters) are released. These activate other nerves that pass signals to the brain.

Within the brain, the message is distributed to brain centres that deal with sensation, thinking and emotion.

Although this mechanism can contribute to chronic pain, it is rarely the sole contributor. This type of pain (nociceptive) tends to resolve with tissue healing and responds well to anti-inflammatories.

Nociceptive pain tends to have a distinct mechanical pattern, i.e. pain with specific movements or postures.

A good example of nociceptive pain would be the pain you experience with an ankle sprain both at the time of injury and with certain movements afterwards.

Neuropathic pain

Another mechanism of pain - which doesn’t involve translating a harmful stimulus into an electrical message - is known as neuropathic pain or nerve pain.

Neuropathic pain is what we experience when there is inflammation, irritation or compression of neural tissue (ie. the pain messaging pathways).

Pain may be accompanied by numbness or weakness in the same region and is often described as burning, shooting, aching or electric shock sensation.

The pain may be referred to surrounding tissues and therefore the source may be elusive and is less likely to respond to conventional analgesics such as anti-inflammatories.

An example of neuropathic pain is referred pain down the leg that commonly accompanies a disc herniation.

Dysfunctional pain

Dysfunctional or centralised pain is characterised by a disturbance in pain processing within the central nervous system (CNS).

This type of pain commences following an initial injury, which causes the nervous system to maintain a state of high reactivity.

Gradually the threshold for what causes pain is lowered, resulting in pain amplification.

Alterations of the pain pathway lead to hypersensitivity, hyperalgesia (exaggerated pain to painful stimuli) and allodynia (pain response to non-painful stimuli).

In dysfunctional pain, a relatively innocuous pain sensation such as a light bump or certain movements will be interpreted as severe pain by the brain. Even the sensation of touch, as with a light massage, will elicit pain.

This type of pain presents in patients with chronic, often widespread pain conditions like fibromyalgia, where there is no noxious stimulus, no detectable inflammation and no structural damage to the nervous system or any other tissue.

Why understanding your type of pain is important

It’s important to recognise that not all pain is the result of damage done to our body (nociceptive) but can be the result of impacts to our pain messaging pathways (neuropathic), or alterations to the function of our pain messaging (dysfunctional).

Understanding your type of pain is essential as this will have significant implications for the type of treatment - particularly the use of medications - as each of these pain mechanisms can be resolved through different medications and treatment choices.

Secondly, the timeframe and severity of the pain can greatly differ with each different type of pain, yet all may be triggered by seemingly similar sets of circumstances i.e. something you did at the gym, worked really long days for a period of time, slept in an uncomfortable bed.

So next time you receive an injury, take a moment to really think about the pain and the level of discomfort.

If your pain becomes too much to handle, or there is no change in your pain over several days, it’s important to see a professional to assess your type of pain/injury and the best methods for treatment.

This will prevent long-term issues and prevent the pain becoming chronic and debilitating as time goes on.