How does pain work in the nervous system?
There are two elements to pain. One of them is the actual irritation of the pain fibre, and then there is the central nervous system perception of it. Acute pain is usually from a local irritation, and that's an easier thing to deal with. It responds to a whole host of narcotics and all kinds of other things. Chronic pain means that your pain has been conditioned, and even though the cause of it is no longer there, you still have pain. The best example of that, really, is phantom pain. Take an amputation of a leg; you say, "Gee, my foot is hurting me." You don't have a foot, but your brain doesn't know that. It's been conditioned. That usually does not respond to narcotics. So, it is the acute pain that you have to differentiate from a chronic pain. In one instance, the chronic pain really has to be dealt with in a different way than simply treating fibre. You have to know that there's not a continuing irritation. So for instance, if somebody has low back pain that goes on for six months, even though it's theoretically chronic pain, the cause of it is still there. This is not what we're talking about, but for instance, say you have a patient who has had something happen to them; they have pain, and they get better from that, but they still have the pain. The pathways are open, it's real pain; it's not imaginative, but the treatment becomes very much more difficult, and it is generally not something that we treat with narcotics.
