All of us have experienced pain at some time in our lives - all of us except for those rare unfortunate people who were born with the inability to feel pain.
Pain is the most common reason people seek medical attention; about 80 per cent of doctor visits are primarily because of some pain problem. The International Association for the Study of Pain defines pain 'as an unpleasant sensory and emotional experience arising from actual or potential tissue damage or described in terms of such damage'. This definition makes it clear that pain is more than just a chemical or electrical signal. Pain can include diverse unpleasant sensations such as aching, tightness, burning and numbness.
Pain also have adverse effects on the body beyond the perception of pain. The physical effects of pain can include:
Fatigue is an important consequence of pain. This was documented in a recent review of 23 reports about the association between pain and fatigue, which found overwhelmingly that they are related and suggested that there may be a cause and effect relationship.
Unrelieved pain also has adverse psychological effects. It causes anxiety, depression, fear, stress, loss of enjoyment of life, and difficulty relating to other people. It can increase marital conflict, reduce sexual desire, and cause feelings of anger and resentment.
Pain is generally thought of being as either acute or chronic. Acute pain results from some trauma to the body - an injury, an operation, or an illness. It usually resolves when the underlying injury has healed or the cause has been treated. Although it is uncomfortable, acute pain serves a useful function: It signals that there is something wrong and motivates the person to get help. Because of the pain caused by an inflamed appendix, most people manage to undergo surgery before the appendix bursts, which constitutes a much more serious surgical problem. Because a heart attack usually causes severe chest pain, an increasing number of people with coronary heart disease are hospitalised early enough to benefit from procedures the prevent further damage to the heart. Acute pain IS beneficial.
Acute pain usually has a clear cause. The same is true for postoperative pain. Doctors are much less reluctant to treat pain whose origin is well understood; but even now postoperative pain is often undertreated. A random sample of 250 adults who had undergone surgery were recently surveyed about their pain experience. Approximately 80 per cent of the patients experienced acute pain after surgery; of these; 86 per cent has moderate, severe or extreme pain, with more patients experiencing pain after being discharged. Experiencing postoperative pain was the most common concern of patients. The study concluded that many patients continue to experience intense pain after surgery.
About 9 per cent of the US population suffers from consistent moderate to severe chronic pain. Several surveys in Europe show that about 18 per cent of people have chronic pain, and the prevalence increases with age. Chronic pain is not just acute pain that lasts longer than a week or a month. It differs from acute pain in several respects. it has become clear that acute and chronic pain are processed differently in the brain. The severity and extent of chronic pain may be out of proportion to the original injury and may continue long past the period in which the damaged tissue has healed. Chronic pain is pain that has outlived its usefulness and is no longer beneficial.
Acute and chronic pain have different treatment goals. The primary goals of acute pain treatment are to diagnose the source and remove it. With chronic pain, the main goals are to minimise the pain and maximise the person's functioning. Diagnosis, of course, a first step, but frequently the source is either already clearly understood (for example, multiple unsuccessful back operations or oesteoarthritis of the knee) or else very poorly understood and unlikely to be better understood (for example fibromyalgia or chronic pelvic pain). In either case, the pain persists and must be treated in its own right. With chronic pain, however, treatment goals must be realistic. Complete relief of the pain is rare. A more realistic goal is to decrease the level of pain to a tolerable level that allows the person to focus on everyday activities. Returning to work is clearly a desirable goal, but in fact, only about 50 per cent of patients who undergo comprehensive multidisciplinary pain rehabilitation are able to return to work.