New light is being shed on the type of pain that has no obvious cause, prompting hope for thousands.

Words: Dr Roderick Mulgan

Pain is a nuisance. It’s not nice to have, but we get why it’s there. Your hand is not improved by contact with an element on the stove, so nature has equipped you to quickly know when that happens and to withdraw without even thinking about it. If we weren’t prompted to act by something objectionable, we would not respond so efficiently. Hence pain — nature’s blunt but effective mechanism for keeping us away from things that aren’t good for us. You don’t like it, but that is the point.

Pain is a constant feature of interactions between doctors and their customers. It probably prompted the first suggestion, back in prehistory, that it would be helpful to have people who could immobilise a broken limb or lance a boil. Physicians have been with us ever since. Scientists know in detail how it all works, with nerve endings sending messages up to bits of the brain that interpret them as noxious and tell that to the owner. It, therefore, seems surprising there is much more to discover about pain. But in 2016, experts admitted that a whole category of pain had been lying under everyone’s noses — overlooked, misclassified, and frequently blamed on imagination and weak will.

The classic concept of pain is two-pronged. It can arise from trauma to tissue, which triggers a message via a nerve. This is “nociceptive” pain and our usual experience of pain day to day. It can also be a malfunction of the nerve itself, like carpal tunnel syndrome (where a nerve in the wrist gets compressed), nerve damage that arises in diabetes, and oddities like phantom pain in an amputated limb. Pain from malfunctioning nerves is called “neuropathic”.

Until recently, everyone thought that was broadly it. Lots of details, of course, but if something hurt, it was one of those two explanations. Either something is attacking you, or a nerve ending is getting triggered off its own bat. Take your pick, but step outside those conceptual spheres, and you are on your own — at least until recently.

In 2016, a seminal paper proposed the term “nociplastic” to account for “a large group of patients without a valid pathophysiological descriptor for their experience of pain”. It was a ground-shifting moment. The term means pain when nothing is malfunctioning. The tissues and organs are normal, but so are the nerve endings. Nothing is out of order. Nothing to see here. Just that it hurts. For years, literature bandied terms like “functional pain” and “somatic symptom disorder” for such symptoms, which were academic ways of saying it was all in the patient’s head.

Even now, many in the medical world haven’t heard of nociplastic pain (neither has the spell check on my computer), and medical workers on the frontline continue to offer psychological explanations, useless pills and professionally controlled exasperation when they encounter it.

The experience of nociplastic pain is not new, but the acceptance and classification are. There are many examples of pain without pathology, like fibromyalgia, i.e., a condition of widespread muscular discomfort and tenderness that lacks an identifiable cause. It is within living memory (20 years or so) that doctors debated whether fibromyalgia was merely a psychological phenomenon. Likewise, irritable bowel, pelvic pain, tension headache and some forms of backache. Do all the tests you like, there is nothing to see but the symptoms.

Sometimes, a territory like a foot or an arm aches or burns for months all by itself. The phenomenon is called complex regional pain syndrome, a phrase which, if you read it twice, simply means the patient says it hurts, and we don’t know why.

Nociplastic pain is usually spread over an area, not a pinpoint. It is commonly severe, even debilitating. Sufferers have long histories of consulting doctors, getting multiple drugs, and not making progress.

They are often fatigued, depressed and have trouble sleeping. These are all factors, incidentally, which have long fed the impression that these people have psychological conditions, not medical ones. Up to a billion people could be affected.

With new understanding comes new approaches. Leaders in the field encourage doctors not to prescribe conventional painkillers for these symptoms. Painkillers tamp down inflammation and block nerve signals, which is useless when inflammation and nerve signals aren’t in play.

These drugs have a comprehensive portfolio of toxic effects, including stomach ulcers, drowsiness and addiction, which are problematic at the best of times and more so when they don’t work. In the same manner, doctors should be cautious about sticking in needles with steroids and undertaking surgery. These things have their place when there is a cause to treat, not when there isn’t.

The most crucial insight is to stop looking for all-encompassing fixes. The issue is as much about living a meaningful life with the symptom as it is about banishing it. Something as simple as having your doctor believe you have been shown to make chronic pain more bearable. The same positive vibe arises from groups for meeting people with similar experiences and learning some of the science behind the symptoms. Cognitive behavioural therapy, a talking therapy where a therapist helps analyse thinking patterns, can give relief.

A more esoteric approach is being trialled with the psychedelic psilocybin, which is the hallucinogenic in magic mushrooms. I wrote about its spooky brain effects in a recent column (NZ Life & Leisure, September/October) — single doses curing depression, for instance — and it crops up here, too. Various trials are underway to see what it can do for exotic pain without a cause. Perhaps something we don’t understand will prove ideal for treating something we don’t understand. Time will tell.

Primum non nocere — first, do no harm — is the motto physicians inherited from the Greeks, where wise heads in Classical times recognised that doctors’ techniques could injure as easily as cure. We aren’t that much further on. There is much medicine can do, but getting the target right matters as much as it ever did. Far too often, patients with nociplastic pain have wound up frustrated, demoralised and injured by their treatments.

With a change of focus, when the doctor seminars and the spellcheckers catch up, people in this category might be destined for a new era of enlightened management and vindication.

FOOTNOTES

1. Bułdyś K, Górnicki T, Kałka D, et al (2023). What Do We Know about Nociplastic Pain? Healthcare, 11(12).
2. Kosek E, Cohen M, Baron R, et al. Do We Need A Third Mechanistic Descriptor For Chronic Pain States? Pain. 2016 Jul;157(7):1382-1386.
3. Some Forms of Chronic Pain Are Particularly Mysterious. The Economist, 30 August 2023.
4. Some Forms of Chronic Pain Are Particularly Mysterious. The Economist, 30 August 2023.

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