Persistent Pain: why won't it stop?
Updated: Jul 20
Last week we discussed low back pain - the most common physical ailment, worldwide. We began to brush the surface of the key questions of why does it occur, and what can we do about it. This week, we tackle a tricky one - why does it persist?
Persistent (or chronic) pain refers to any pain or discomfort that has been present for longer than 3 months, even if you only notice it intermittently.
It can range from a mild annoyance that you just can't seem to shake to a something totally debilitating that dominates your thoughts and energy. In any case, there are a few different reasons why pain persists.
We've already spoken extensively to the role of psychological and social factors in the perpetuation of pain, so we'll leave that one alone for now. Today, let's dive into a key neurological factor that contributes - Central Sensitisation.
Sounds pretty complex, right?
To be honest, it is pretty complex. I'm not going to lie to you. But give me a chance before you hit the eject button. I'll try to simmer it down to just the necessary ingredients so that it's a bit easier to digest. Let's go.
Central Sensitisation - your body's alarm system
To understand Central Sensitisation we first need a short refresher on pain itself. In a nutshell, pain looks something like the following:
Some form of stimulus (impact, heat, chemicals, etc.) comes in contact with your body
The sensory receptors (nociceptors) in your skin that tell your brain "this feels bad!" send danger signals up your spinal cord to your brain.
Your brain does its thing and determines whether pain is necessary, based on the information that it received, your beliefs, your mindset, and your past experiences.
If the amount of danger that your brain concludes exceeds a certain threshold - which is something that changes and is different for each individual - then voilà, we have pain.
Image taken from: http://neurowiki2014.wikidot.com/group:pain
Now, it's the threshold part of this that we want to touch on. Let's say we have a sliding sale from 0 (being nothing at all) and 10 (being maximum stimulation), and the threshold for us to experience pain sits somewhere along this scale.
In normal times, my threshold may sit at a 7/10 - where 7 reflects a certain volume or intensity of stimulation (e.g. movement, heat, cold, etc.).
But how does this relate to persistent pain?
Well, as we experience pain for an extended period, the sensitivity of those nociceptors - the ones that scream "bad!" to our brain, can increase significantly. This is what we refer to as central sensitisation.
Central sensitisation results in a hypersensitivity to things that are not typically painful
As the sensitivity of the system increases, we end up requiring less and less stimulus for our brain to produce pain. This hyperactivity lowers the threshold of what the brain needs to produce pain, which can result in pain persisting even after the initial injury has healed.
For example, with my hypothetical low back pain, I may have initially only experienced pain when I lifted something heavy - exceeding my threshold of 7/10. But now, after experiencing persistent pain for several months, the sensitivity of my system has increased dramatically and now I experience pain just by simply bending over - my threshold has reduced to, let's say, 2/10.
Think of it like a home alarm system. When the system is operating normally (7/10), it will alert you when intruders enter the house, but won't go off when a small mouse crawls through the kitchen. As the system becomes more sensitive (2/10), that small mouse starts to set the alarm off, even though it is not a danger to the house.
The brain senses danger so it decides to produce pain, but that does not mean that we are doing any damage.
In fact, in most cases it's quite the opposite. Moving your body in a controlled, thoughtful, and progressive way, is the best long-term remedy for an oversensitive system.
So there you have it. A bit of a brief overview of why pain can persist for long periods, even after the original injury has healed.
I won't get into a detailed treatment plan here and now. If this has resonated with you and you feel compelled to dig a little deeper, please feel free to shoot through an email.