Compiled by our Masters trained Physiotherapist Chris Smith. To book an appointment with Chris, or read his Meet the Team profile CLICK HERE.
Today we're going to talk about pain! Although most of us don't like the sensation, pain plays a vital role in protecting us and is necessary for our survival. Pain is a universal human experience and is defined as "An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage" (IASP). But what can the type of pain tell us? Can it help us to identify which tissues are causing the pain and can it guide how we target treatment? Well yes and no, it can certainly give us some clues, hence why physiotherapists spend time in your initial assessment asking so much about pain.
Before we start, pain is a complex topic and the world's leading researchers are still learning more every year. Most tissues in the human body including ligament, muscle, tendon, bone, and nerve all have the ability to produce pain. The 3 main stimuli that produce pain are mechanical, thermal and chemical. For example when you overstretch and roll your ankle (mechanical stimuli), when you burn your hand (thermal) stimuli.
When a tissue is damaged, such as when a ligament is strained, sensory pain receptors (nocioreceptors) in that tissue start a process and send signals into your central nervous system, where it travels up your spinal cord to your brain. Here the decision is made how much of a pain experience to produce in the injured tissue based on many factors such as past experience, beliefs etc. This process is called nocioception.
This is usually a good thing as a pain response prompts us to change our behaviour and allows for rest and recuperation of damaged tissue.
Broadly speaking pain can be classified into nociceptive pain, neuropathic pain and other pain, such as visceral pain from organs.
This is the term for pain arising from various kinds of injury in the tissues, reported to the brain by the nervous system. This is the most common type of pain most people are most aware of - anything from stubbing your toe, straining your back or burning your hand.
This can be split further into mechanical and inflammatory pain. These types of pain can present differently and the characteristics can help in differentiating the painful tissues. For example low back pain that is present with a certain movement, but absent otherwise indicates that the low back tissues are responsible for the pain. Also, knee pain which is present only when loading the joint during walking may lead a clinician to diagnose a joint based condition such as osteoarthritis.
However, pain that is more constant in nature may have an inflammatory component. This is quite normal following a tissue injury as there is a natural inflammatory process in order to promote tissue healing. However, when constant pain starts without a tissue injury it may be that an inflammatory condition is primarily responsible for the pain. Examples of this would be rheumatoid arthritis or gout.
This arises from damage to the actual nervous system itself. This could be the nerves that supply the skin/muscles (peripheral nerves) or the central nervous system (brain/spinal cord). The most common examples of this are pinching or compression of spinal nerves by a disc prolapse in the spine or hitting your funny bone. Disease of the brain from stroke and multiple sclerosis can give central neuropathic pain. It's often stabbing, electrical, or burning, but nearly any quality of pain is possible making it sometimes difficult to differentiate from nociceptive pain. The presence of sensory changes such as pins and needles/numbness/tingling and weakness can differentiate this type of pain.
We are often asked if pain descriptors (such as sharp, dull, aching) can guide us to the source of the tissue damage. Research has shown this can be quite difficult and unreliable in humans, especially with nociceptive pain and the classic "feels like a pinched nerve" could just as likely be produced from a disc, ligament of joint. There are some cues as mentioned above for neuropathic pain which can be useful in guiding diagnosis. However, using the subjective pain information in addition to assessment findings is essential to making a more accurate diagnosis.
Most often the pain signal reduces in intensity as the tissues heal (often 6-12 weeks), however sometimes as the tissues heal the pain signal still stays heightened (in 25% of people). Pain that does not settle in 3-12 is termed chronic or persistent pain, and this is likely due to the nervous system response remaining heightened after tissue healing has occurred. This is termed central (nervous system) sensitisation and can be thought of as the volume on an amplifier being turned up too high. Or like a sensitive car alarm going off with a strong gust of wind. The gust of wind is not dangerous anymore, but the car alarm (brain) is too sensitive. Physiotherapists and healthcare professionals can use techniques to reduce the sensitivity of the nervous system and help with this persistent pain.
The good news is whether your pain is acute or persistent it is possible to get it under control. Speaking to a health professional and having an assessment will allow a physiotherapist to understand more about the drivers of your particular pain and situation. This will enable a personalised management plan to be produced to target your pain. So if you're in pain right now make an appointment to come and see myself or one of our team who are experts in pain management.