Just Curious About Pain Tolerance

Shoreline

Hi Vik, I have spent years reading about chronic pain, how it's different from acute pain, the biochemical responses involved but I really haven't run across any major studies comparing one persons ability to handle pain better than others.

Basically to summarize one study, they used a large gage needle and inserted it into the trigeminal nerve and ran electric current through the needle to produce what most people would consider severe pain. Then people were asked to rate their level of pain and the results were that everyone basically interprets pain differently, some people rated pain at a 5 and some rated the pain at a 10, the worst pain they can imagine, and every other number in between. There was no consensus on how painful this was, other than yes it did hurt.

I believe the reason you have such a large variation in the population is that rating pain is completely subjective. How could the worst pain you can imagine be the worst pain I can imagine if you haven’t experienced the levels of pain I have? So you’re looking for a definitive answer on a subjective rating system.

What do you want to base your findings on. What the patient says, what their physiologic responses are, such as BP and pulse, vomiting, or even attitude or mood of the patient when observed.

For example I was waiting to be checked out and sitting in the hall after an apt where I desperately needed an adjustment in my IT pump after a change from morphine to Dilaudid. There are charts to convert a dose of morphine to a dose of Dilaudid but even the charts vary. They are simply guides to safely get you in the ballpark and then adjustment must be done to obtain equal relief from a different opiate.

So I'm sitting there hoping the increase just made will start to make a difference in about 10 hours. MY BP was 158/96 10 minutes earlier and I rated my pain as a 7, I felt like puking and couldn't stand without my legs shaking and had sweat dripping from my nose. A nurse takes a patient back to be seen and asks this patient how is her pain today. She said it had been awful the past few days, but right now it was a 9 on a scale from 1-10, 10 being the worst pain you can imagine. She seemed cheerful, didn't appear to be in any distress at all but rated it one step below where in my mind most people wold be on the way to the ER or passing out.

I wanted to ask the patient if she believed if her pain had been any worse, she wouldn't have been able to make the apt and would be on her way to the hopital by ambulance sobbing. She certainly didn't appear to be in that kind of distress, she was well kept, clear headed and would apear fine to anyone that observed her. But who am I to say this is almost the worst pain she has ever experienced or could possibly imagine. A 9 to me means I can't catch my breath, My BP and pulse are through the roof and I'm sweating profusely. Obviously my 9 produces a different reaction than her 9 on the standard Irandal scale of rating your pain from 1-10.

I've had 3 back surgeries and prior to each surgery I had been in more pain than I had ever experienced, but I never rated my pain a 10 because I was sure a gun shot to the knee cap or thigh or having my arm ripped off by a piece of farm equipment would likely be more painful than the level of pain I was experiencing. After the first surgery I did well for about 8 months. I had discontinued opiates and was back at work when I reinjured my back. This time the diagnostic findings were much worse than the prior injury requiring more invasive surgery.

At that point I was experiencing more pain than I had ever experienced, but I could still imagine being in worse pain. That surgery completely failed, the fusion failed to grow, the hardware snapped and I was forced to discontinue meds 8 weeks post op and went through 3 years of pain management of every kind except opiates.

They didn't want to turn me into an addict and each doc I saw had the answer as to how to manage pain and used the same technique on every patient they saw. It wasn't until vertebrae shifted and crushed enough nerves to the point of loosing bowel and bladder control that they went back in to replace the broken hardware, revise the fusion and straighten out my spine. That surgery went from a simple 3 level fusion to a 6 level fusion. I woke with more pain than I had ever experienced. It left me bed ridden for 9 months until a doctor finally used enough opiates and other meds that allowed me to stand in the shower without support.

I'm disabled and had a heart attack after 2 years of living like that at the age of 36 with a cholesterol level of 108. The heart attack was the only pain I would call a 10. Looking back, it was extremely painful but that could have been heightened by the fear of death.

The pain I had experienced prior to my first surgery that I rated as a 9 at the time would now be a 4 on my revised pain scale. With each surgery, unimaginable pain became reality and I had to reset my subjective pain scale accordingly.

You can study, GABBA, Glutamate, NK-1, NMDA receptors, Substance P , and Every other neurotransmitter, calcium channel activity and chemical reaction that occurs but won't be able to explain why one person would call a root canal the worst pain they can imagine and why another would rate it a 3 on their pain scale.

Certainly there are psychological factors, Expectations of pain relief, Pain that has been experienced and pain that you can imagine.

For example, when the do a trial for an Intrathecal pump, they are looking to reduce a patient’s pain by 50%. That's considered a success and reason to go ahead with the implant when pain can't be managed orally or the side effects are too bothersome. 50% relief will allow some people to go back to work and lead a fairly normal life. 50% to someone else may mean they are now able to shower without help and spend 20 minutes on their feet before the pain goes through the roof and sweat starts dripping from their nose.

Your trying to quantify a subjective feeling which can't be done. I've passed over 30 kidney stones, which would send most people to the ER doubled over and puking. Since the last failed back surgery I would call a kidney stone a minor inconvenience that didn't require medical attn. Unless I began to feel it was obstructing my kidney which has happened a half a dozen times.. It's not that I'm claiming to handle pain better than someone else, but compared to what I have experienced, certain things just aren't going to rate high if you asked me to rate that level of pain with a number.

AS far as the psychology aspects of pain management and what they can offer, is mostly coping mechanisms like self hypnosis, guided imagery or biofeedback and simply learning to except the changes in yur life. I learned them all long before OxyContin was even on the market. I am able to relax during extreme periods of pain, it requires laying down, lessening my level of awareness or consciousness which allows me to catch my breath, slow my breathing, raise my skin temperature as much as 10 degrees, and actually fall asleep within 15 minutes. However once up and walking around again, with all the normal stimuli in life, including the pain of standing, I'm not able to maintain that level of altered consciousness or awareness.

There really isn't an absolute answer for what your asking, why do some people interpret stimuli as excruciating and some as a minor annoyance? Personally I don't think the answer is in the biochemistry but in the experience of the individual. I'm sure there are lots of psych theories but it's a giant leap from theory to the actual pain experience that nobody contemplating the psychology of the pain wants to actually experience themselves. Slammng your hand in the car door to measure glutimate levels is one thing, leaving it crushed in that same door for 5 years is completely different.

Good luck with your research, if you have any other questions I would be happy to share my POV.
Take care, Dave

BTW, there is more to chronic pain than a simple increase in glutamate. There are huge differences between the bio and neuro chemistry of acute pain and chronic pain and the way it's interpreted. Not to mention the psychological fatigue from living with chronic pain. This article explains it well.
http://www.hosppract.com/issues/2000/07/brook.htm