IV.

Pain Control

The body has many mechanisms that amplify or reduce pain. When cells are damaged, they release chemicals, such as bradykinins and prostaglandins. These chemicals intensify pain sensation both by making nociceptor nerve endings more sensitive and by causing inflammation around the damaged cells. Without these chemicals, nociceptors would cease transmitting pain information as soon as the source of injury was removed. Some scientists suspect that bradykinins activate nociceptors in the first place.

Other mechanisms reduce pain sensation by blocking, or inhibiting, the transmission of the pain message to the brain. To alter the pain sensation, the brain and spinal cord release specialized neurotransmitters called endorphins and enkephalins. These chemicals interfere with pain impulse transmission by occupying the nerve cell receptors required to send the impulse across the synapse. By making the pain impulse travel less efficiently, endorphins and enkephalins can significantly lessen the perception of pain. In extreme circumstances, they can even make severe injuries nearly painless. If an athlete is injured during the height of competition, or a soldier injured during combat, they may not realize they have been injured until after the stressful situation has ended. This happens because the brain produces abnormally high levels of endorphins or enkephalins in periods of intense stress or excitement.

In addition to the body’s own mechanisms, humans have devised many different ways to manipulate the body’s ability to control pain. Drugs that relieve pain, known as analgesics, usually interfere with pain impulse transmission in the nervous system. Narcotic analgesics, such as codeine, have chemical structures that are similar to the pain-blocking neurotransmitter endorphin. Other drugs that relieve pain alter the way damaged nerves transmit information. Nonsteroidal anti-inflammatory drugs, such as aspirin and ibuprofen, are analgesics that reduce pain by inhibiting the synthesis of prostaglandins, the body chemicals that intensify pain and cause inflammation.

Another way humans control pain is by injection of drugs that temporarily deaden the nerves that transmit pain signals. These drugs bring about anesthesia, a loss of sensation that renders the body completely or partially insensitive to pain, or even touch. Local anesthetics, such as procaine, deaden nerves in a particular area of the body but interfere little with other body functions. General anesthesia renders people unconscious so they do not feel pain at all. People who undergo general anesthesia also have no memory of events that occurred while they were unconscious.

Many people learn to control their pain with strategies that do not rely on drugs or surgery. Some people control the normally involuntary components of pain message transmission using a behavior modification technique called biofeedback. Acupuncture is widely used for pain relief. Many scientists now believe that this ancient medical procedure may trigger the release of endorphins and enkephalins, the body’s own pain-inhibiting neurotransmitters. Others suspect that the pain-relieving attributes of acupuncture are due, in part, to a patient’s expectation of relief. Although it is not completely understood, physicians and pain specialists have found that when a person suffering from pain expects that a particular procedure—in this case acupuncture—will make their pain subside, it actually does.

In cases where no treatment effectively relieves pain, doctors may recommend a surgical procedure in which pain-transmitting nerves in the brain or spinal cord are severed. Only a small fraction of pain sufferers need such surgical treatment. Another pain-relieving procedure involves placing electrical stimulators on the skin, nerves, spinal cord, or brain to reduce pain sensation.

Some injuries take a long time to heal, and even then, pain does not always completely subside. People suffering from this condition, known as chronic pain, may continue to experience debilitating pain for years, without having any apparent tissue damage. This may be the result of permanent damage to the nervous system. There is new evidence that the nerves in the spinal cord and brain can alter their connections after severe pain—that is, even after healing, the nervous system never returns to normal. Pain that subsides and then returns periodically, such as headaches or low back pain, also falls under the category of chronic pain. In their search for pain relief, many chronic pain sufferers become dependent on strong painkilling medicines, and they often fall into an endless cycle of pain, depression, and inactivity.

The complexity of human pain often requires a combination of pain therapies to achieve relief. Pain management specialists are usually medical doctors with specialized training in neurology, psychiatry, or surgery who have restricted their practice to the analysis and treatment of pain. Psychologists are usually important members of a pain management team. Many people are turning to alternative healthcare practitioners, such as those that specialize in acupuncture or chiropractic, for pain relief. Often, pain management specialists and practitioners of alternative pain therapies join forces in multidisciplinary pain clinics.