Neuropathic pain, in contrast to the nocioceptive variety, is chronic pain in which the nerve fibers themselves have become damaged or dysfunctional. As a result, the fibers send incorrect signals that are perceived as pain. Neuropathic pain usually follows a tissue injury, and you might feel it as either pins and needles, a burning sensation or an electrical shock.
Neuropathic pain can occur when nerves that usually respond to an injury become active for no reason -- that is, they "fire" but are not responding to anything specific. This can happen anywhere in the nervous system, which is generally divided by area into peripheral and central systems. With neuropathic pain, the function of the nerves becomes compromised and nerve activity increases. Left unchecked, this activity causes other nerves to become ultra-sensitive, leading to altered responses to felt sensations, such as allodynia.
Sometimes symptoms of neuropathic pain do not correspond to a change in anatomy or lesion. At this point the doctor, especially one unskilled in pain management, may tell you "it’s all in your head." But in reality, there are some types of neuropathic pain that are the result of disruption of function, rather than a problem detectable with an MRI, CT scan or other diagnostic imaging technique.
Neuropathic pain may last for a very long time and cause the sufferer to constantly be looking for something to relieve it. In general, this type of pain does not respond very well to painkillers. If your pain persists, your doctor may suggest invasive pain management procedures or back surgery.
Sources:
Gould, H., MD, Phd. Understanding Pain: What It Is, Why It Happens, and How It's Managed. AAN Press. 2007. St. Paul, MN.
Guyton, A., MD, Hall, J., MD. Textbok of Medical Physiology. 11th ed. Elsevier Saunders. 2006. Philadelphia.
Hanline, B., MD. Back Pain Understood: A Cutting-Edge Approach to Healing Your Back. Medicus Press. 2007.
