There’s pain, damn pain and then there’s neuropathic pain. And who of us can tell which is worse.
The problem with pain is that we still don’t entirely understand it: its causes; our experiences of it; and often how to treat it. All we know is that, if somebody is suffering from it, it can be seriously debilitating and affect every aspect of their life.
On the surface, pain seems simple. Something happens to the body that could cause it damage, that area of the body sends a pain signal to the brain, the brain responds with a sensation we call pain to try to get us to stop doing the damaging thing. We stop. The pain fades.
So why do we experience pain even when there’s no underlying cause, such as in cases of fibromyalgia? Why do people with depression feel more pain than those without? Why do anti-depressents help with chronic pain? Why do placebos work predominately on our subjective experience of pain? And why do some people with nerve damage, such as stroke patients, experience chronic burning, tingling, pins and needles, numbness or itching in limbs that are otherwise paralysed?
The latter is called neuropathic pain and it can be very disabling for the person experiencing it. Neuropathic pain is defined as ‘pain arising as a direct consequence of a lesion or disease affecting the somatosensory system’. In laymen’s terms, either the brain or the nerves themselves have been damaged and can send a pain message to the brain unnecessarily. One good example of neuropathic pain is phantom limb syndrome, which occurs when an arm or a leg has been removed because of illness or injury. The brain still gets pain messages from the nerves that originally carried impulses from the missing limb. These nerves now misfire and cause pain.
Because there’s no actual damage to the limb, neuropathic pain can be particularly difficult to treat with standard pain medication. It’s not a case of targetting inflammation or other underlying causes of pain because there is no underlying cause for the pain other than the damaged nerves or brain. Neuropathic pain can also be progressive so the patient’s experience of it can become more severe over time.
Since the stroke, Mum has suffered from pain believed to be neuropathic along her left side: reporting a sensation of ‘pins and needles’, burning and other pain sensations. These are particularly bad in her left hand and her left leg and often interfere with her ability to do rehabilitation exercises. Mum’s neuropathic pain was the reason her FES therapy was so stressful for her and why she used to hyperbolically refer to it as ‘torture’.
For the last three months, Mum’s neuropathic pain has been treated with paracetamol, anti-depressants and Lurica, an anti-convulsent that helps to slow or block uncontrolled pain signals. Unfortunately, the combination of these drugs have not been sufficient to relieve Mum’s pain so this week SACU is trying a five-day regime of Lignocaine infusions (also known as Lidocaine): an anaesthetic. Another drug infusion used for neuropathic pain treatment is ketamine and much of the pain literature references the use of both.
Research into Lignocaine infusions has shown varied results from the infusion in the treatment of neuropathic pain with some research indicating that it is more effective than a placebo in treating neuropathic pain and other research overviews calling the evidence “sparse”. There are, unfortunately, short-term side effects (although most of these subside quickly once the treatment ends). Mum will be extremely tired and may also suffer from numbness around the mouth, dizziness, tinnitus (ringing in the ears) or slurred speech. However, a lignocaine (or lidocaine) infusion is often recommended in cases like Mum’s where almost no oral pain medication can be administered. And the treatment is considered a useful diagnostic tool for confirming a patient’s pain really is neuropathic.
We can only hope the series of infusions is not too stressful on Mum due to the side effects and that the infusions work in reducing or (dare I say it) eliminating her neuropathic pain.
My old friend Novella of course has a post on his blog that references neuropathic pain and explains it quite well. Don’t be put off by the title as there isn’t really such a thing as ‘psychogenic’ pain, as he makes clear. Pain is always “real”. By definition.
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