If I turn my head quickly I get an electrical zap in my neck. When I was a teenager I had a lymph node removed and during the procedure a nerve was damaged. Because nerve regrowth is likened to fingernail growth it took twenty years for the area under my chin to get feeling back. It was always kind of cold and numb. It felt rubbery when I touched it and If anyone else touched my neck I would jerk away as it felt tingly and weird. Nerve pain is described as a constant burning, tingling, electrical, stabbing, or pins and needles. It can present as abnormal sensitivity to temperature and noxious stimulation. Even though I don’t live with nerve pain, I do understand people’s descriptions when they say things like: “it feels like my foot’s not there but then it’s twice as large as it should be.” I had that too - but on my neck.
Here’s a picture showing the neuropathic pain pathway. It shows different mechanisms that can trigger nerve pain and how medication might be used accordingly. As if it was that simple.
The different points show:
Pain sensitivity in the damaged area due to increased activation of inflammatory mediators leading to increased sensitivity and excitability in the nerves.
Direct insult to nerves producing cell death or compromising the transmission of sensory information.
A change in gene expression in the spinal cord triggered by Inflammatory messengers that makes neurons more excitable and so transmit more pain messages.
A structural rewiring in the spinal cord can result in the loss of calming neurons (inhibitory interneurons) and a promotion for touch sensors into pain detectors.
Descending Facilitation means that there is a down regulation of calming (inhibitory) neurotransmitters (norepinephrine and serotonin) while at the same time there is increased excitability and reduced firing thresholds of the pain messengers.
The pain neuro-matrix up regulates. The areas of the brain that generate, amplify and interpret sensory information as pain do this more readily than usual.
There may be a genetic predisposition for nerve pain. People have been found to have markers that predict positive or negative susceptibility to nerve pain.
While I’m here I’ll include a neat picture of the ways that your nerve pain may have been diagnosed with this Diagnosis for neuropathic pain flow chart
Now I need to show you some less fun images. This table from this text book shows the wide range of treatment options that are used to treat nerve pain.
The problem is, none of these treatments work terribly well - as shown in this image of success rates of common neuropathic pain treatments from here
This table shows that of the six most common treatments “do not improve” was represented in higher numbers than “improves with treatment” for each option.
And, when we look at this table outlining the benefits and harms of neuropathic pain treatments, we see that of the common treatments used, only four of them can be considered to be more beneficial than harmful. Of these four the NNT (number of patients that need to be treated in order to have an impact on one person) ranged from seven to ten people and the adverse events of dizziness and somnolence applied to the top three options.
Taken together, these tables reflect how difficult treatment for neuropathic pain is.
What to do then? Well, there are gentler approaches that you can try. I've listed them below.
Menthol Cream
menthol is a natural compound derived from mint oils. It produces a cooling or tingling sensation when applied to the skin. It activates cold receptors (called TRPM8) in the spinal cord so that the nerves pass on cooling messages instead of pain signals. It may also desensitise nerve endings in the skin, reducing their sensitivity to pain signals. Deep heat and tiger balm both have menthol in them.
Lidocaine patches
Lidocaine is a local anaesthetic that is applied to the skin as a plaster. It inhibits both the generation and conduction of nerve impulses. It stabilises nerve membranes and reduces spontaneous firing of pain messages in damaged nerves. Talk to your doctor if this is an approach you’d like to try.
Capsaicin Patches
Capsaicin interferes with the transmission of pain signals from the nerves to the brain. This is called “defunctionalisation of nociceptor fibres.” It does this through two main processes. First it turns the switch off at the junction where pain messages should be passed on; and it dials down the activity of sensory nerve endings involved in the perception of pain and temperature. Capsaicin patches can be purchased online or prescribed by a doctor.
TENS
TENS stands for Transcutaneous (through the skin) Electrical Nerve Stimulation. TENS machines are thought to stimulate sensory nerves with electrical currents that override or interfere with pain signals, reducing the perception of pain. They need to be used for an hour a day for at least a week. They are non invasive and (relatively) cheap so are worth a try.
Nutrition
Lots of studies show reductions in neuropathic pain with vitamin and mineral supplementation. The anti inflammatory diet of no processed foods, no sugar, no grains is used successfully for people with MS. Here is a TEDx talk that explains why we need to feed our mitochondria for nerve health. Good nutrition is one pillar of good health along with sleep, exercise and stress reduction. Living healthily is good for the nervous system and also reduces inflammation - two elements that help to reduce pain.
Graded Motor Imagery
GMI Focuses around retraining the mental map we have of the body. It starts with looking at pictures of your affected body part and discriminating left and right. Here’s a picture from the recognise app to show what I’m talking about
From here you work towards visualising your affected body part moving without pain. If walking across a room causes you pain, you would first visualise getting up from a chair, then once the brain has been taught that this action shouldn’t be causing pain, the imagery can move onto visualising walking a few steps; progressively continuing until you have visualised yourself reaching the other side of the room.
This book here explains this process in greater detail
Sometimes Mirror training is used as a way to change the image that the mind has of the body. You hide the affected limb in a box with a mirror or with a large mirror and move the unaffected limb. The reflection of the unaffected limb moving easily tricks the brain into thinking movement has occurred without pain.
Coping Imagery training
Asking a person to imagine tasting a lemon has been shown to increase salivation; visualising physical activity increases heart rate; and imagery of white blood cells attacking germs has been shown to produce immune system change . Pain coping imagery is the generation of an image that overrides the image you hold of your pain. If your hand feels like it is on fire you might visualise it being submerged in cool water. It is hypothesised that coping imagery may dial down your pain through influencing evaluation and decision making pathways related to your pain.
Rewiring pathways in your central nervous system takes time. If you use any of these approaches you will need to commit to them for at least a month before you see a difference. Neuropathic pain is pretty rubbish. I hope one of these things helps.
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