Another topic I want to squeeze in before the year ends: Boot Nail Guy, practically a mascot for “pain science.” This fellow has been rather hotly debated by the pain dorks on social media since the early summer, so I’m a bit late to the party. But many readers will be hearing about this for the first time; part of my job is to report (and translate) what the pain dorks are debating. So what’s this all about?
The legend of Boot Nail Guy:
A builder aged 29 came to the accident and emergency department having jumped down on to a 15 cm nail. As the smallest movement of the nail was painful he was sedated with fentanyl and midazolam. The nail was then pulled out from below. When his boot was removed a miraculous cure appeared to have taken place. Despite entering proximal to the steel toecap the nail had penetrated between the toes: the foot was entirely uninjured.
JP Fisher, senior house officer, DT Hassan, senior registrar, N O’Connor, registrar, accident and emergency department, Leicester Royal Infirmary
Stories like this — tales of pain with little or no injury — seem to show that a pain experience can be powerfully modified by the mind, if not conjured up out of almost nothing. If we can be spooked into agony, that seems like an important data point.
But what stories are there? Boot Nail Guy is the best known extreme example of pain-without-injury. It was reported in the British Medical Journal in 1995. Originally rather obscure, it has been widely cited for many years since being popularized as an example of how pain is “an output of the mind,” which is a major modern hypothesis about how pain works: namely that the brain processes all incoming sensory data as well as all kinds of high-level context, and only then generates an experience of pain. If true, the main implication is that pain is modulated by the brain.
“Boot Nail Guy” has been the best well-known demonstration of that idea. But is best example good enough?
Can a nail between the toes actually fool someone into thinking they’ve been impaled? Image courtesy of Andrew Dixon, Radiopedia case 36688. Nail Photoshopped into the image for dramatic effect.
First things first: is the Boot Nail Guy citation cromulent?
There is at least a somewhat credible source (see Fisher). If you are determined, you can verify the citation with a free trial membership for BMJ.com. But here’s the thing: there is just not much to verify! It’s not a scientific paper. It is not even a formal case study. It is barely more than a photo with a caption! It was just a sidebar in the full text of the “Minerva” column (a compilation of snippets of interest).
Despite the lack of detailed documentation, there is not much reason to doubt the gist of the story. Boot Nail Guy probably did have an unpleasant trip to the hospital, and yet was not actually seriously injured.
But without detailed documentation, there are many reasons to doubt that the story is exactly what it seems to be, or that it actually constitutes compelling evidence of pain-without injury, let alone pain-without-nociception (“nociception”: nerve impulses generated by potential tissue threats).
What really happened? The range of possibilities
It is quite possible that the incident did not play out just as described, and even likely that meaningful details were omitted. Did Boot Nail Guy really need sedation, for instance? Was he actually in terrible pain? Or was he just extremely anxious? And who wouldn’t be in that situation?
Was he actually “entirely” uninjured? Or could he have been just sightly injured, damage so minor that the story ignored it? A “seed” of nociception from minor trauma is quite different than none at all.
Can someone even mistake a nail between the toes for being impaled through the forefoot? It seems like it should have been obvious that the injury was probably less serious than that — based on the position of the nail alone. This might be more of a story about an oddly intense emotional reaction than warped perception. It seems plausible to me that the gist of the story is not so much perfectly uninjured person experiences terrible pain, and more like slightly injured person is really freaked out until proven safe.
Does any of this support the claim of pain-without-nociception?
Obviously this slightly formal anecdote is not compelling evidence of pain without any injury/nociception at all. I do think it can give some modest support to that idea; it can be a possible example of a sensory experience that was probably powerfully exaggerated by the mind — though I think we must still remain open to the possibility that it was more an experience of panic rather than pain. Indeed, it raises the interesting question of how to even tell the difference! If someone says they are in pain, contradicting them is not really possible (or compassionate), any more so than telling someone they are not really in love.
If we accept that the Boot Nail Guy legend is real and more or less accurate, then it probably is a good example of a classic nocebo — the opposite of a placebo. Instead of relief from belief, it’s grief from belief.
But there’s a reason it gets cited so much: it may be a legit example, but it is also the only widely known or cited example of allegedly fear-powered pain.
Where are the other pain-without-injury stories?
Beets are the most common source of “blood” in the stool & urine. Photo by Evan-Amos.
I know of an anecdote from a professional, about a man who was rescued from agony by learning that his bright red poop was caused not by internal bleeding but… beets! Where did all the “agony” come from? Certainly not the beets. It may be hard to distinguish between agony and panic, which is partly the point. This is actually a common example of nocebo in medicine: people eat beets, think there’s blood in the toilet, and call 911. Funny if it’s not you! They don’t all have pain, but some do. (The story is told in Marni Jackon’s superb book, Pain: The science and culture of why we hurt.)
If there are other weird tales of great pain with no apparent cause, they are hard to find.
It makes sense that they would be both rare and/or under-reported. It probably takes a bit of a perfect storm for a person to truly believe that they are badly injured… and yet turn out to be uninjured. And fewer still would be clear enough to justify a formal case report. Such incidents would be more of a medical novelty with no significance — interesting to pain science wonks, but probably not most doctors.
But they may be the tip of an iceberg of more ordinary cases of pain out of proportion to the injury, which would definitely be under-reported: “injury seemed a lot more painful for the patient than I would have expected” is probably so common that it’s barely worth a story at a dinner party … let alone a formal case report.
The phantom phantom (← not a typo)
Although there is no one specific legend like Boot Nail Guy, phantom limbs have also often been recruited as a major example of brain-generated pain, in the absence not just of a problem with tissue, but the absence of the tissue itself! If a limb doesn’t exist, the argument goes, then obviously the pain cannot be coming from it! Checkmate?
But there’s another good explanation: we know that the signalling is coming from the stump, from the ends of the severed nerves. Those signals are then misinterpreted by the brain, leading to the perception that it’s a missing arm that’s hurting. From the brain’s perspective, those signals came from the same place that arm signals come from, ergo arm. (See Ilfeld; this information is not new, but that study was particularly good.)
So that is all very interesting neurology, but it is also not really an very good example of “pain is an output of the brain,” inventing a sensation out of nothing, and we should all probably stop using it that way. But it is still a good example of how the brain can generate an painful experience that isn’t just what it feels like.
This is a modified excerpt from PainScience.com’s main article about the nature of pain: Pain is Weird.