Pain

Pain is the body’s response to an injury or disease that results in tissue damage. Pain usually functions as a protective warning mechanism that helps to prevent further damage, although chronic (long-term) pain often seems to serve no useful function. Everyone has experienced pain, but its type and severity depend to some extent on the cause. For example, pain that results from a sports injury may be less severe than that of a similar injury caused by a violent assault. Mood and personality also affect the way we perceive pain. For example, fear or anxiety can make pain worse, while relaxation may help to relieve it to a certain extent.

The brain and spinal cord produce their own painkillers, known as endorphins, in response to pain. Endorphins, are natural chemicals that are closely related to morphine and act as highly effective pain relievers for short periods but are less effective for chronic pain.

Most forms of pain can how be controlled as a result of improvements in treatment, and it is rare for someone to have to live with persistent pain.


What are the causes?

When tissue is damaged by trauma, infection, or a problem with its blood supply, specialized nerve endings called pain receptors are stimulated. Electrical signals travel along the nerves and through the spinal cord to the brain, which interprets them as pain. While this is happening, the damaged tissues release chemicals known as prostaglandins, which cause inflammation and swelling. The prostaglandins further stimulate the pain receptors. The skin and other sensitive parts of the body, such as the tongue and the eyes, have a large number of pain receptors and are therefore very sensitive to painful stimuli. The internal organs of the body have fewer pain receptors and are insensitive to most types of injury.

What are the types?

Although each individual may describe the character or the site of pain in a different way, there are some types of pain that usually result from specific problems. For example, throbbing pain is often due to increased blood flow, either as a result of widening of the blood vessels, as may occur in migraine, or because of an increase in blood flow through injured tissues. Severe, shooting pains, such as sciatica, can be caused by pressure or irritation of the nerve at the point where it emerges from the spinal cord. Colicky pain is caused by intermittent stretching and contraction of muscles in the walls of the intestines, or in other parts of the body such as the bile ducts, which lead from the liver to the intestine.

The location if the pain usually acts as a good guide to its source. However, in some cases, overlapping nerve path-ways can result in a confused message, causing pain to be felt in a different area of the body from the site where it originates. This type of pain, known as referred pain, occurs when nerves carrying the sensation of pain merge with other nerves before they reach the brain. For example, hip problems may be felt as knee pain, while problems with a tooth may be felt as earache. Heart problems, can cause pain across the chest, into the neck, and in one or both arms. Pain due to problems in the intestines tends to be felt in the centre of the abdomen and is felt locally only when the abdominal wall is affected, as in the late stages of appendicitis.

Sudden (acute) severe pain may be associated with other symptoms, such as pale skin, sweating, nausea or vomiting, rapid pulse, and dilated pupils, and may even result in fainting. Prolonged period of severe pain that continue for weeks or months may lead to depression, loss of weight as a result of decreased appetite, and disturbed sleep.

What might be done?

If you experience severe or recurrent unexplained pain, you should see your doctor who may be able to establish the cause of pain after a physical examination. Further investigations, including blood tests and imaging tests such as ultrasound scanning, may be necessary if there is no obvious cause.

Since it is difficult to measure the severity of pain, your doctor may ask how the pain affects your sleep and your ability to cope with daily activities. You may also be asked to describe the severity of the pain on a scale of 1 to 10 for almost unbearable pain.

The most effective remedy for pain is treatment of the underlying cause, if possible. However, pain relief is also important until treatment of the cause takes effect. There are many different ways to relieve pain, including drugs and physical methods. The form of pain relief chosen depends on the cause and type of pain you experience.

Since pain, especially persistent pain, is influenced with other factors such as personality and levels of stress, treatment has to be tailored to the individual.

Drug treatment: virtually all short-lived pain and much long-term pain can be relieved by painkillers. When pain is caused by local prostaglandin release, treatment with a non-steroidal anti-inflammatory dugs such as ibuprofen often works well because these dugs limit the release of prostaglandins.

Opioid drugs, such as morphine and codeine, act directly on the part of the brain that perceives pain and are usually highly effective. Opioid drugs may be needed to relieve intense pain, such as that following surgery, and the severe pain associated with some cancers. The risk of addition to these drugs is small when they are used for short periods, and dependence is not a cause for concern when they are used in caring for a terminally ill person.

In addition to painkillers, a number of other drugs are prescribed for certain types of pain. These include local anaesthetics and drugs that affect the transmission of nerve impulses, such as anti-depressant drugs and anti-convulsant drugs. Pain that is caused by muscle tension may be relieved by small doses of anti-depressants. Anti-convulsant drugs are often used to treat pain associated with neuropathies, such as trigeminal neuralgia.

Physical treatment: a wide range of non-drug therapies is available to help to relieve pain, including gentle massage and the use of hot or cold compresses. These treatments both after blood flow through damaged tissues and stimulate other nerve endings, blocking pain.

Acupuncture is helpful for some types of helpful for some types of pain and may be used to relieve pain after operations or for persistent pain that does not respond to other types of treatment. Acupuncture is believed to work by causing the brain to release endorphins or by stimulating nerve endings near the site of the pain so that they stop sending pain messages.

If your pain is due to damaged ligaments or muscles, your doctor may offer ultrasound treatment, in which sound waves produce vibrations in the tissues and generate heat. Transcutaneous electrical nerve stimulation uses electric impulses to reduce pain by stimulating the nerves and is sometimes used for lower back pain or during labour.

What is the prognosis?

Almost all pain can be relieved to some degree, even if the underlying cause of the pain cannot be definitively treated. However, persistent pain is often more difficult to control than acute pain.

PAIN RELIFE USING TENS

Transcutaneous electrical nerve stimulation (TENS) is sometimes useful for relieving severe, persistent pain, such as back pain. In TENS, electrical impulses are relayed from an impulse generator to electrodes placed on the skin in the area of the pain. After about 30 minutes, pain may be significantly reduced. Relief may last for several hours. TENS can be used while pursuing normal activities.