Pain begins by the activation of specific nerves that are called A delta and C fibers. The A delta are fast nerve fibers and carry information for fast changes, like pulling your hand back from a hot burner. The C fibers are slower and carry information to prevent further injury of an area. The pain that comes after the burn that feels like the deep throbbing/burning pain.
Pain is considered to be chronic if it has been present for longer than three months. The type of pain may vary greatly and may be felt as bone pain, nerve pain or muscle pain. The sensation of pain may also vary. For instance, pain may be aching, burning, stabbing or tingling, sharp or dull, and well-defined or vague. The intensity may range from mild to severe.
What causes chronic pain?
Chronic pain may be caused by many different sources. It may start from diseases, injuries or stresses to many different structures including bones, muscles, ligaments, joints, nerves or the spinal cord. The affected structure will send a signal through nerve endings, up the spinal cord and into the brain where it registers as pain. Many different theories try to explain chronic pain. The exact mechanism is not completely understood. In general, it is believed that the nerve pathways that carry the pain signals from the nerve endings through the spinal cord and to the brain may become sensitized. Sensitization of these pathways may increase the perceived pain out of proportion to the source of the pain. Stimuli that ordinarily are not perceived as painful, such as light touch, can be amplified or changed by these sensitized pathways and experienced as pain. Sometimes, even after the original injury or disease process has healed, sensitized pathways continue to send signals to the brain.
Stress and Pain
Anxiety and stress can actually increase your perception of pain and reduce your pain coping skills.
It is important to remember that there is a dynamic relationship between your state of mind (eg, stress level) and your physical condition (eg, pain). Pain can cause stress, which causes more pain, which causes more stress, and so on. The more chronic this vicious cycle becomes, the more likely your emotional distress will increase. This cycle can be very difficult to break.
Emotional suffering can lead to loss of sleep, inability to work as well as feeling irritable and helpless about what can be done. You may feel desperate and attempt to relieve the pain at any cost including the use of invasive medical procedures.
Chemical and physical changes in the brain
The constant stress, anxiety and pain have a major impact on the chemical released in the brain and the actual structure and size of the brain. The area of the brain that receives and processes most of the pain and emotional information is the frontal cortex. Because of all this information there is a change in the chemicals in this area that lead to a more emotional state and can lead into depression. With acute pain, the pain is reduced and these chemical changes return to their normal state. With chronic pain, the pain is constant and these chemical changes become the normal state for your body, thus there is a greater tendency to develop depression and emotional changes. There are also changes in the size of the frontal cortex with chronic pain. Research has shown that the size of the frontal cortex decrease with chronic pain. Research has also shown that this change in size is reversible.
The executive functions of the frontal lobes involve the ability to recognize future consequences resulting from current actions, to choose between good and bad actions (or better and best), override and suppress unacceptable social responses, and determine similarities and differences between things or events. Therefore, it is involved in higher mental functions.
The frontal lobes also play an important part in retaining longer term memories which are not task-based. These are often memories associated with emotions derived from input from the brain’s limbic system. The frontal lobe modifies those emotions to generally fit socially acceptable norms.
The chemical and physical changes to the frontal lobes can lead to a variety of results: Mental flexibility and spontaneity are impaired, but IQ is not reduced, talking may increase or decrease dramatically, perceptions regarding risk taking and rule abiding are impaired, socialization can diminish or increase, orbital frontal lobe changes can result in peculiar sexual habits, dorsolateral frontal lobe damage reduces sexual interest, creativity is diminished or increased as well as problem solving skills, distraction occurs more frequently, loss of smell and/or taste.
Fortunately, there are a number of psychological therapies that have been successfully used in the management of pain and anxiety. These include stress management, relaxation training, biofeedback, hypnosis and cognitive-behavioral therapy (a method to reduce feelings of doom and helplessness). There are also medications available to help with sleep problems, anxiety and depression. Such comprehensive pain management programs, when integrated with your medical care, have proven to be quite successful. Your health care provider can refer you to a psychological management program if it is appropriate. Participation in such a program does not mean the pain is “all in your head” – it is meant to teach you methods to cope with and control the pain. Remember, pain is a complex experience that includes a close interaction of physical and psychological factors! But together, you and your health care providers can help you manage and overcome your pain.
Knowyourback.org from the North American Spine Society.
Information from the American Psychological Association.