Pain is the body's response to injury and inflammation. There are nerve cells called pain receptors that are located all over the body, including the internal organs. Paradoxically, the brain itself has no comparable pain receptors, which is why neurosurgeons can perform a procedure called [awake craniotomy] to perform [brain mapping] procedures. [web link] Pain can be a very simple problem, such as that arising from a nerve being compressed as it exits the spinal cord. “Neuropathic” or “central” pain, on the other hand, refers to discomfort that arises in the nervous system, but at no specific location. This type of pain is sometimes described as diffuse or burning, although sensations such as cold, numbness, or “pins and needles” fall in this category. An example of neuropathic pain is diabetic neuropathy, which causes numbness and tingling in the hands and feet. In mood disorders such as depression, the perception of pain is sometimes heightened; this is referred to as “somatization,” emotional distress that is expressed as a physical symptom.
Pain can be treated with over-the-counter (OTC) acetaminophen (Tylenol) and nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Motrin) or naproxen (Aleve); or prescription medications such as indomethacin (Indocin) or celecoxib (Celebrex). Narcotic medications for pain include acetaminophen with codeine (Tylenol-3) or oxycodone (OxyContin). Narcotics carry the disadvantage of being habit-forming, requiring increased dosages over time to treat the same amount of pain. Joint pain can sometimes be relieved by periodic injections of steroidal drugs.
Some types of pain, such as that resulting from injuries, osteoarthritis, or muscular spasms, can be relieved by targeted physical therapy. Regular exercise can both relieve pain and improve the stress often associated with pain. Meditation, stress reduction, and biofeedback techniques that increase physical awareness can also be quite helpful in moderating the body's response to pain.
For persistent pain that is not relieved by drugs, a nerve block can be used to prevent the irritated nerve from communicating pain back to the spinal cord and brain. A nerve block is an injection that contains a numbing drug such as lidocaine, and is delivered directly to the site that is causing pain, such as a vertebral disc. While not a permanent solution, this procedure can often bring about relief for weeks or months. In cases of chronic pain, which is often associated with other medical problems, a pacemaker-like device can be implanted in the brain to interrupt the “pain circuit” with continuous electrical signals. This procedure is called [deep brain stimulation] (DBS).