My work is full of unexplained pain.
A woman spends three days in the hospital with severe abdominal pain, but is cleared of every possible ominous medical cause … and then comes to see me!
A man gets a ride in an ambulance with severe chest and left shoulder and arm pain, but doctors cannot find anything wrong with him … and then he comes to see me!
A woman writes to me and asks:
I’ve been to every medical specialist you can imagine. They can’t find anything wrong with me. The psychiatrist says it’s not in my head, and the rheumatologist says it’s not in my body. But something is causing my pain. It’s not an infection or a fracture or a cancer. It’s not a sprain or a pinched nerve or a little man with a knife. What else is there? What else is left?
What else indeed! When commonly known causes of pain have been eliminated, what next? What else causes pain? How else can pain start, change, worsen? This article summarizes nine not-so-obvious ways to hurt: nine pain phenomena that might help you to understand pain that has defied diagnosis or explanation so far.
One of the principle qualities of pain is that it demands an explanation.
Plainwater, by Anne Carson
Muscle knots — myofascial “trigger points” — are a factor in most of the world’s aches and pains. Their biology is still mostly mysterious: conventional wisdom says they are tiny spasms, but they might also be a more pure neurological problem. Regardless, they can cause strong pain that often spreads in confusing patterns, and they grow like weeds around other painful problems and injuries, making them quite interesting and tricky. Although they are well known to many specialists and researchers, most doctors and therapists know little about them, so misdiagnosis is epidemic. See Save Yourself from Trigger Points & Myofascial Pain Syndrome.
Molecules like prostaglandin E2 and serotonin make pain receptors “louder,” sending more pain messages to the brain. This is called “sensitization.” There are complex physiological circumstances in which these molecules become more prevalent than they should, perhaps in a specific area, or even systemically. This is not a specific diagnosis. No doctor will ever tell you “you’ve got sensitization.” But it is an important basic concept to help you understand why you might hurt mysteriously.No doctor will ever tell you “you’ve got sensitization,” but it is an important basic concept.
Sometimes, the brain intensifies pain as a consequence of stress, anxiety, and fear. This is not “all in your head” pain, but “aggravated by your head” pain. Like an ulcer, there is a real physical problem — but it just happens to be unusually sensitive to your emotional state. Sometimes, the brain’s interpretation of a situation becomes a major part of the issue. Like picking at a scab, the brain can become excessively focussed on a pain problem. For more information, see Pain is an Opinion.
Complex regional pain syndrome is a terrible disease which causes extreme pain, usually in a limb, due to massive and poorly understood dysfunction of the nervous system. The severity and general nastiness of this condition cannot be understated. I include it here not because CRPS is a possible diagnosis for less severe pain, but because — like many extreme phenomenon — it tells us something about how the body works … or doesn’t work. It tells us that some pain is definitely caused by “malfunction” of the nervous system. Not a nerve pinch or lesion, but nerve failure. Many times in my career I have become quite convinced that a patient was suffering from some lesser form of CRPS, a neurological dysfunction severe enough to cause extreme misery, yet not bad enough to be diagnosed as true CRPS.CRPS tells us something about how the body works … or doesn’t work.
Ordinary muscle tension itself can cause a surprising amount of pain. A leg or foot cramp is a common and extreme example, where no one has any doubt of the cause of pain. But imagine a muscle spasm much less strong, but lasting for days and days — or years! Although superficially a simple concept, there are actually several physiological mechanisms by which muscle can become shortened and painful for a long time, and it is not well understood. Muscle can even be spasmed from birth for unknown reasons, as in torticollis (wry neck). And if your muscles are spasmed for long enough, they will actually “freeze” like that: essentially scarred into place, a phenomenon called “contracture” which is difficult and sometimes impossible to treat.
Anything that hurts inside the body — anything under the skin — is difficult for the body to locate. This is partly because we literally just don’t have enough nerve endings for it, and partly because the nervous system isn’t perfect and signals literally get “crossed.” The practical result of this is that internal pain with any cause may be felt somewhere completely different. Despite the fact that this phenomenon is well known, it still results in an amazing amount of medical barking up the wrong tree. Referred pain isn’t exactly a “cause” of pain, but it belongs in this list because it’s an important concept that can help to explain many pain problems that otherwise don’t make sense. For instance, both of the examples at the beginning of this article were cases where referred pain fooled doctors — in both cases, the pain was caused by a trigger point in a nearby muscle, not by vital organs. The doctors simply looked in the wrong place!Referred pain results in an amazing amount of medical barking up the wrong tree.
Here’s a simple experiment: assume an distinctly awkward posture, and within minutes you will probably experience severe pain. Why? You haven’t ripped or torn anything. But we are wired to avoid this situation, because every cell in our body depends on nearly constant movement to survive. And so the nervous system takes it very seriously whenever tissues feels “stuck.” The exact mechanism of pain is probably nerve endings that detect tension on cartilage, ligaments and tendons. Continuous tension on these structures may be interpreted by the nervous system as a serious threat. But here’s the kicker: you can induce this reaction quickly with an obviously awkward posture … or you could do it slowly and insidiously with surprisingly subtle poor posture, muscle imbalances, joint dysfunctions, or anything that deprives tissue of full movement. When a joint feels “stuck,” for instance, and there is no obvious way (and sometimes no anatomical way) of moving to get “unstuck,” the sensation can escalate to a screaming itch-you-can’t-scratch. This is probably one of the main causes of neck cricks, and scads of other miscellaneous aches and pains. Unfortunately, postural correction is a challenging and sketchy business.
On January 7, 2008, the U.S. Food and Drug Administration alerted health care professionals and consumers to the unusual severe side effects of a popular class of drugs for osteoporosis and Paget’s disease, the bisphosphonate (Wikipedia). They can cause “severe and sometimes incapacitating bone, joint, and/or muscle pain” which “may occur within days, months, or years” after first taking the medication. This medication has almost certainly explained some otherwise inexplicable pain in some of my patients over the years! Alendronate and risedronate are the two most popular bisphosphonates, and they are usually prescribed for osteoporosis or for a bone-deforming condition called Paget’s disease. If you are 40+ and grappling with a mysterious pain problem, check your medicine cabinet for bisphosphonates in particular, but of course any other medication that could cause pain as a side effect.
This almost counts as a drug side-effect, but it’s an important enough phenomenon in its own right that it deserves to be included here. When you take a lot of analgesics — pain-killers — it’s possible to pre-empt the production of your body’s own pain-fighting molecules. Endorphin production, for instance, will drop. This can have disastrous consequences when you stop taking the drugs, resulting in worse pain than ever. This is part of the phenomenon of the well-known serious withdrawal symptoms from some drugs; it is a less well-known problem with over-the-counter pain-killers. Although this phenomenon isn’t particularly mysterious or difficult to identify, it does show us something important about how pain works: we aren’t entirely without our own defenses, and those defenses can actually be undermined by artificial help. And there are scenarios where analgesic rebound may be difficult to detect. Given how extremely common analgesic usage is, it’s likely that people with recurrent headaches may suffering primarily from bouts of rebound pain, occurring in the occasional gaps between erratic but generally intensive self-prescribing of pain killers. I have a good story about a terrible withdrawal-induced headache: see my headache tutorial.
And of course all of these phenomenon can and regular do get mixed up together in unholy combinations, most of them having the capacity to cause or complicate any of the others. It certainly keeps my job interesting.