"Quit being such a pain in the butt." "He broke my heart." "Ouch... that was a bit harsh, don't you think?"
All of these statements bring to mind some form of pain, though not usually the form we tend to associate with the word 'pain'. After reading an article the other day (I'll get to that in a bit), I began thinking about what exactly pain is. Obviously, when you do some sort of damage to yourself, and it hurts, it's called pain. Hospital patients are told to rate their pain on a scale from 1 to 10, 1 being no pain, and 10 being the worst pain you've ever felt (though, my dad says a 10 would mean that you aren't sane enough to say a ten, because it hurts so badly.
But what about other forms of pain? Emotional and mental pain? Referred pain? Sympathetic pains? How do we determine if those are real?
Furthermore, for people who can't tell us that they're in pain, or even animals who can't tell us, how can we tell? Is it the anguish on their faces? Their blood chemistry? What?
Well, let's start with the basics. Pain is a mechanism your body has to tell you you're hurt in some way. It is part of the innate immune system, right alone with your skin and your macrophages. So, when you fall and hit your knee, it's gonna hurt.
Why? Because there are some nice little nerve endings in your body that send signals to your brain telling you so. Which brings us to referred pain. Many of these nerve endings share endings with other parts of the body. For example, your heart shares the same nerve for pain as your left arm. Sometimes, your brain mistakes the end it's coming from, and interprets it the other way. So, when your heart is experiencing pain (say... during a heart attack), you don't feel it in your chest, but rather along your left arm.
According to the article I read, though, pain involves a lot more than that. Pain stimulates the release of a whole bunch of hormones, in an attempt to get you out of the situation that is causing you pain. Among other things, cortisol and adrenaline are released. When the response is extreme enough, it could kill you from shock. This is, of course, why we administer anesthesia to patients undergoing surgery.
Up until recently, infants were not getting anesthesia, and many were dying after major surgery. Why weren't they getting anesthesia? Because doctors didn't believe they experienced pain (this of course gets into a big long discussion that I care not to right now, so we're going to focus on things after birth). Many are still iffy on the subject. Why?
Well, how do you know you're in pain? You say it hurts, right? But two people experiencing the exact same stimulus... say a pinprick to the finger... one could feel only a minor discomfort, and the other could experience a fair amount of pain.
So we look to the hormones, right? But those specific hormones are stress hormones, so they can be produced by the body under physical or emotional stress. Lifting heavy boxes all day could potentially release these hormones, if you are not used to doing so. Does it hurt? Maybe, maybe not. Additionally, as the article points out, these hormones are elevated in brain dead patients as well during organ harvesting. Do we think they can feel pain as well?
Which brings me to another point. Emotional stress can lead to physical pain. Ever study for finals or exams so much that you literally get sick to your stomach? Ever had tension headaches? Ever been depressed? Each of these has an emotional event (or series of events) at its foundation, and yet causes physical pain. (Similarly, physical pain can lead to emotional stress.)
So, what is pain? It's obvious that it's some subjective value. Two people could not experience the same level of pain with a specific stimulus. Does this mean infants, who have the capability, but perhaps not the experience, to process pain, might not feel it? At which point does pain develop, and what is required, anatomically, to process it?
This question obviously has far reaching implications. To those who cried in outrage of Terry Shiavo, you can see the implications... starving a person to death isn't very humane if they can feel it. Of course, since euthanasia is currently banned in the US, where would that leave us? Do children with a damaged cortex still feel pain? The questions can go on and on...
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