There are many paths to pain that never make headlines.

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There are many paths to pain that never make headlines.

34 Surprising Causes of Pain

Trying to understand pain when there is no obvious explanation

Paul Ingraham ,  updated  Sep 5, 2019

The world is full of unexplained pain, with many dozens of possible causes. By far the most important thing to understand about treating chronic pain is that it is difficult because it almost never has  one cause: it is extremely  multifactorial. It’s always a game of Whac-A-Mole with chronic pain — but some really strange moles (and well-camouflaged too).

I publish a busy website about pain, and so I get email like this more often than I change my socks:

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 cattle prod. What else is there? What else is  left?

What else indeed? When “obvious” and known causes of pain have been eliminated,  what next? What else causes pain? How else can pain start, change, worsen? This article summarizes 34 of the not-so-obvious ways to hurt, the things that might help you understand pain that has defied diagnosis or explanation so far. There are a lot more possibilities, but it’s a start, and this article hopefully focusses on the most important.

A lot of pain is unexplained

The “official” causes of all kinds of chronic pain break down into three roughly equally large categories, plus one small “other” category: 1

  

· injury (38%)

· unknown (31%)

· musculoskeletal (24%), a vague category dominated by arthritis, the rheumatic diseases, and headache

· other (7%), which is mostly cancer and abdominal pain plus “everything else” (mostly pain related to major physiological systems)

Misdiagnosis is routine, of course. Arthritis and the rheumatic diseases should probably be in their own major category, and almost everything else filed under “unknown.” Pain after injury is surprisingly murky: sure, it might have started with an injury, but two years later is that still the “cause”? It has usually transmogrified into something else, and exactly how that works is much more about the “unknown” than “injury.” Many cases of chronic pain are hard to put in just one of these categories (or they only  seem easy to place). As you browse around this article, you’ll notice that most causes of pain are hard to categorize.

Table of Contents

Basic mechanisms, processes, and concepts (potentially relevant to many injuries or illnesses, and a lot of these overlap partially or even completely):

· Sensitization (somatic and visceral)

· Chronic pain does not work like acute pain

· Psychological amplification

· All in your head: pure psychosomatic pain

· Pain with literally no specific cause

· Muscle spasm, tension, contracture

· Referred pain

· Spatial summation

· The pain of stuckness

· A genetic defect that exaggerates all sensation

· Stupid, stupid neutrophils

· Chronic subtle inflammation and “inflammaging”

· Neuroinflammation

· Unexplained neuropathy (especially channelopathy)

· Non-obvious nerve entrapment

· Loneliness & social isolation

And some specific pathologies (things that can be diagnosed, and in some cases treated)…

· Trigger points

· Complex regional pain syndrome (CRPS)

Fibromyalgia? By definition, fibromyalgia is  unexplained chronic widespread pain. It is not in itself a “cause” of pain. Read  more about fibromyalgia .

· Myelopathy (spinal cord impingement, especially and probably intermittent)

· Claudication: the pain of impaired blood flow

· Ehlers–Danlos syndrome and the hypermobility spectrum disorders

· Nutritional deficiencies: vitamin D and magnesium

· Mitochondrial disease

· Chronic immune activation after infection

· Syphilis

· Early stages of …

· Facioscapulohumeral Muscular Dystrophy (FSHD)

· Autoimmune diseases

· Multiple sclerosis

· Lymphoma

· Drug related:

· Side effects, especially statins, bisphosphonates, fluoroquinolones, retinoids

· Opioid-induced hyperalgesia

· Analgesic rebound

· Benzodiazepene withdrawal (both erratic and chronic)

If I included every disease that causes aches and pains, this list would wrap around the Earth. I’ve narrowed it down to problems that are particularly notorious for both (a)  evading  diagnosis and (b) causing  primarily  aches and pains and other vague, non-specific symptoms (and not other symptoms that would easily lead to a diagnosis). Some of them are in a gray zone, of course.

Some more topics I’m considering for future updates to this article:

· multiple level radiculopathy (similar in spirit to subtle/intermittent myelopathy)

· painful anatomical oddities like os trignum syndrome (and there are quite a few of these actually)