Recent research has helped to shed more light on the changes that occur in your body with chronic pain.
What is Normal ‘Protective’ Pain?
Normally pain is good. It informs you about potential or actual damage to your body’s tissues. Nociceptor nerve cells in the tissues of your body, react to strong stimuli such as pressure, heat, cold or chemicals.
These nociceptors send a message to the spinal cord, which then forward another message up to the brain. Your brain then processes these messages and produces a coordinated response to escape whatever is causing the tissue damage.
What is ‘Pathological’ Pain?
Research has shown that changes occur in your body at all levels of pain processing. These changes include:
Changes at the Injury Site
At the site of the injury, your peripheral nerve becomes much more easily excitable. This means that it takes far less of a stimulus to cause it to fire off. In some cases, even a gentle brush against the skin is enough to fire off the pain pathway.
Unfortunately, it is not just the damaged nerves that become more excitable, but also the neighbouring nerves, which means even further amplification of the nerve messages. Some nerves can also start firing off spontaneously, which means that they do not need a stimulus to fire off.
Changes in your Spinal Cord
In the dorsal horn of the spinal cord, changes occur in some of the cells that receive the nociceptor messages. These changes lead to greater sensitivity to the spontaneous nociceptor messages mentioned previously. Changes can also occur in some cells that leads to a ‘memory’ developing between two cells, which leads to an amplified response in the neighbouring cell.
Changes in your Brain
Usually, your brain can decrease the level of pain you experience by releasing natural opioid hormones. When you suffer chronic pain, changes occur in the midbrain which actually increases the nociceptive messages. This means you’ll perceive even more pain.
Chronic pain messages stimulate parts of the brain involved in emotion, fear and feelings. This may help explain why conditions such as depression, sleep disorders and pain catastrophising are linked with chronic pain.
We also know that chronic pain leads to atrophy or ‘shrinking’ of parts of the cortex and midbrain. Brain-stimulating activities may help to limit this ageing.
Do You Need More Information about Chronic Pain?
If you need more information about your pain or how to best manage your chronic pain, please consult the advice of your physiotherapist. Your physiotherapist is highly trained at helping you to understand and reverse the changes that occur with chronic pain.
What is Pain?
Pain is the built-in alarm that informs you something is wrong!
Pain is your body’s way of sending a warning to your brain. Your spinal cord and nerves provide the pathway for messages to travel to and from your brain and the other parts of your body. Pain travels along these nerve pathways as electrical signals to your brain for interpretation.
Receptor nerve cells in and beneath your skin sense heat, cold, light, touch, pressure, and pain. You have thousands of these receptor cells. Most cells sense pain. When there is an injury to your body, these tiny cells send messages along nerves into your spinal cord and then up to your brain.
In general, pain receptors are classified according to their location.
Receptors that respond to injury or noxious stimuli are termed nociceptors and are sensitive to thermal (heat), electrical, mechanical, chemical and painful stimuli. Each nociceptor is connected to a nerve that transmits an electrical impulse along its length towards the spinal cord and then, ultimately, your brain.
It is your brain that informs you whether or not you are experiencing pain. Plus, your pain can plays tricks – especially when you suffer chronic pain.
Pain messages travel slower than other nerve stimulation.
Nerves can also be categorised according to their diameter (width) and whether a myelin sheath is present.
Three types of nerves are concerned with the transmission of pain:
A-beta fibres, which have a large diameter and are myelinated
A-delta fibres, which has a small diameter and also have myelinated sheaths.
C fibres have small diameters, are non-myelinated (slowing their conduction rate), and are generally involved in the transmission of dull, aching sensations.
Nerves with large diameters conduct impulses faster than those with a small diameter. The presence of a myelin sheath also speeds up the nerve conduction rate.
One method of easing your pain is to provide your nervous system with high speed “good feelings”, such as rubbing your injured area. This is the same principle that a tens machine (pain-relieving machine) utilises to provide pain relief.