PERSISTENT PAIN: When things go wrong
Welcome to the second article in the UNDERSTANDING PAIN series.
If you missed the first article outlining the science of pain, you can read it here.
In today’s article, I will outline exactly what becomes dysfunctional in the different parts of the body and nervous system when pain becomes chronic and persistent.
In a healthy pain response, all of the elements that make up your pain experience will reverse and return to normal over time, in line with the healing of the injured tissue. But sometimes, things don’t behave as they should and pain persists.
There is no simple answer for why this occurs and there are often a number of different factors, each unique to the individual case.
Regardless of the reasons, the fact of the matter is that your danger alert system has malfunctioned. Whilst in a normal scenario the level of pain will diminish as the injury heals, with chronic pain the level of pain you experience remains the same or even worsens over time, even if the injured area is healing normally.
When pain becomes chronic, the pain you feel is no longer an accurate representation of danger or damage in your body.
There are detectors in your body that monitor pressure, temperature and chemical changes. In order for these to send a danger message to the spinal cord, the stimulus has to be strong enough. For example, if you touch your skin lightly right now, you won’t feel pain because the pressure isn’t strong enough to activate the danger detectors. But if you pinch yourself hard or place a boiling hot object on the skin, this activates the detectors, which will send a message to the spinal cord.
When pain becomes persistent, these sensors begin to change the way they work. They start sending danger messages to the spinal cord even if the stimulus isn’t dangerous, such as light pressure or a tiny change in temperature. And instead of just sending one message, they send lots and much faster. Think of it like opening the floodgate – you now have detectors that are oversensitive and sending false danger messages.
The spinal cord
Your spinal cord needs to become excited enough before it will alert the brain to danger. In states of persistent or chronic pain, the spinal cord becomes overexcited, a bit like an untrained puppy. Danger messages that the spinal cord would normally ignore coming from the detectors seem like a big deal and it rushes off to inform the brain. In fact, it multiplies the danger messages and makes them even bigger.
You now have oversensitive detectors and an overexcited spinal cord that are both alerting your brain about danger that either doesn’t exist or is over-exaggerated.
When pain persists, your brain begins to change to get better at protecting you. The word neuroplasticity describes how your brain is ‘plastic’ in the way it can adapt and change. There are several ways in which your brain adapts to become more protective.
When your danger system is working normally, your brain can accurately identify the area of potential harm in the body. With chronic pain, your brain map for sensation begins to smudge and the outline of the painful body part begins to expand. To you, this may feel like the pain is spreading and covering a larger area. In reality, this is just the brain trying to be clever and protect more ground.
Another way that your brain changes with pain is by becoming really efficient at activating the areas and chemicals associated with the sensation of pain. The longer you feel pain, the more effective your brain becomes at producing the experience. It’s like anything – the more you practice, the better you get.
Other body systems
Because your brain has interpreted that there is danger and has produced a pain response, it now calls on the other body systems to enter ‘fight-or-flight’ mode. Your sympathetic nervous system is very effective in helping you escape from danger and prepares your body for action, such as increasing your heart rate and breathing. It also gives less attention to things like digestion, sexual function and your immune system when you are in imminent danger. Whilst a short blast of fight or flight can be good, in chronic or persistent pain you often remain in this heightened nervous state for long periods. The result of this can be anxiety and panic, restlessness, sexual dysfunction, problems with digestion, chronic fatigue, a weak immune system and higher levels of alertness to pain.
Hopefully you can now appreciate how pain can persist, even after an injury has healed!
Article 3 will demonstrate an example of a positive vs a dysfunctional pain response in 2 different people.
In the final article I will outline the best strategies for overcoming chronic pain.
Stay tuned :)