Pain management





Definition

Pain management covers a number of methods to prevent, reduce, or stop pain sensations. These include the use of medications; physical methods such as ice and physical therapy; and psychological methods.

Purpose

Pain serves as an alert to potential or actual damage to the body. The definition for damage is quite broad; pain can arise from injury as well as disease. Pain that acts as a warning is called productive pain. After the message is received and interpreted, further pain offers no real benefit. Pain can have a negative impact on a person's quality of life and impede recovery from illness or injury. Unrelieved pain can become a syndrome in its own right and cause a downward spiral in a person's health and outlook. Managing pain properly facilitates recovery, prevents additional health complications, and improves a person's quality of life.

For many years it was believed that infants do not feel pain the way older children and adults do. As of the early 2000s, however, there has been a better understanding of the problems of pain, even in infancy.

Description

Before considering pain management, a review of pain definitions and mechanisms may be useful.

What is pain?

Pain is the means by which the peripheral nervous system (PNS) warns the central nervous system (CNS) of injury or potential injury to the body. The CNS comprises the brain and spinal cord, and the PNS is composed of the nerves that stem from and lead into the CNS. PNS includes all nerves throughout the body except the brain and spinal cord.

Once the brain has received and processed the pain message and coordinated an appropriate response, pain has served its purpose. The body uses natural pain killers, called endorphins, that are meant to derail further pain messages from the same source. However, these natural pain killers may not adequately dampen a continuing pain message. Pain is generally divided into two categories: acute and chronic.

Acute and chronic pain

Nociceptive pain, or the pain that is transmitted by nociceptors, is typically called acute pain. This kind of pain is associated with injury, headaches, disease, and many other conditions. It usually resolves once the condition that caused it is resolved. However, following some disorders, pain does not resolve. Even after healing or a cure has been achieved, the brain continues to perceive pain. In this situation, the pain may be considered chronic. The time limit used to define chronic pain typically ranges from three to six months, although some healthcare professionals prefer a more flexible definition and consider pain chronic when it endures beyond a normal healing time. The pain associated with cancer , persistent and degenerative conditions, and neuropathy, or nerve damage, is included in the chronic category. Also, constant pain that lacks an identifiable physical cause, such as the majority of cases of low back pain, may be considered chronic.

It has been hypothesized that uninterrupted and unrelenting pain can induce changes in the spinal cord. As of 2004 evidence was accumulating that unrelenting pain or the complete lack of nerve signals increases the number of pain receptors in the spinal cord. Nerve cells in the spinal cord may also begin secreting pain-amplifying neurotransmitters independent of actual pain signals from the body. Other studies indicate that even newborn and premature infants who have constant pain will reach adulthood with greater sensitivity to pain and lower tolerance of stress.

Managing pain

Considering the different causes and types of pain, as well as its nature and intensity, management can require an interdisciplinary approach. The elements of this approach include treating the underlying cause of pain, pharmacological and nonpharmacological therapies, and some invasive (surgical) procedures.

Treating the cause of pain underpins the idea of managing it. Injuries are repaired, diseases are diagnosed, and certain encounters with pain can be anticipated and prevented. However, there are no guarantees of immediate relief from pain. Recovery can be impeded by pain, and quality of life can be damaged.

Pharmacological options

Pain-relieving drugs, otherwise called analgesics , include nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen , narcotics, antidepressants , anticonvulsants, and others. NSAIDs and acetaminophen are available as over-the-counter and prescription medications and are frequently the initial pharmacological treatment for pain. These drugs can also be used as adjuncts to other drug therapies, which might require a doctor's prescription.

NSAIDs include aspirin, ibuprofen (Motrin, Advil, Nuprin), naproxen sodium (Aleve), and ketoprofen (Orudis KT). These drugs are used to treat pain from inflammation and work by blocking production of pain-enhancing neurotransmitters, such as prostaglandins. Acetaminophen is also effective against pain, but it is not an anti-inflammatory drug.

NSAIDs and acetaminophen are effective for most forms of mild pain, but moderate and severe pain may require stronger medication. Narcotics handle intense pain effectively and are used for cancer pain and acute pain that does not respond to NSAIDs and acetaminophen.

Narcotics may be ineffective against some forms of chronic pain, especially since changes in the spinal cord may alter the usual pain signaling pathways. Furthermore, narcotics are usually not recommended for long-term use because the body develops a tolerance to narcotics, reducing their effectiveness over time. In such situations, pain can be managed with antidepressants and anticonvulsants, which are also only available with a doctor's prescription.

Although antidepressant drugs were developed to treat depression, it has been discovered that they are also effective in combating chronic headaches, cancer pain, and pain associated with nerve damage. Antidepressants that have been shown to have analgesic (pain reducing) properties include amitriptyline (Elavil), trazodone (Desyrel), and imipramine (Tofranil). Anticonvulsant drugs share a similar background with antidepressants. Developed to treat epilepsy, anticonvulsants were found to relieve pain as well. Drugs such as phenytoin (Dilantin) and carbamazepine (Tegretol) are prescribed to treat the pain associated with nerve damage.

Other prescription drugs are used to treat specific types of pain or specific pain syndromes. For example, corticosteroids are very effective against pain caused by inflammation and swelling, and sumatriptan (Imitrex) was developed to treat migraine headaches.

Drug administration depends on the drug type and the required dose. Some drugs are not absorbed very well from the stomach and must be injected or administered intravenously. Injections and intravenous administration may also be used when high doses are needed or if an individual is nauseous. Following surgery and other medical procedures, patients may have the option of controlling the pain medication themselves. By pressing a button, they can release a set dose of medication into an intravenous solution. This procedure has also been employed in other situations requiring pain management. Another mode of administration involves implanted catheters that deliver pain medication directly to the spinal cord. Delivering drugs in this way can reduce side effects and increase the effectiveness of the drug.

Nonpharmacological options

Pain treatment options that do not use drugs are often used as adjuncts to, rather than replacements for, drug therapy. One of the benefits of non-drug therapies is that an individual can take a more active stance against pain. Relaxation techniques, such as yoga and meditation, are used to decrease muscle tension and reduce stress. Tension and stress can also be reduced through biofeedback, in which an individual consciously attempts to modify skin temperature, muscle tension, blood pressure, and heart rate.

Participating in normal activities and exercising can also help control pain levels. Through physical therapy, an individual learns beneficial exercises for reducing stress, strengthening muscles, and staying fit. Regular exercise has been linked to production of endorphins, the body's natural pain killers.

Acupuncture involves the insertion of small needles into the skin at key points. Acupressure uses these same key points but involves applying pressure rather than inserting needles. Both of these methods may work by prompting the body to release endorphins. Applying heat or being massaged are very relaxing and help reduce stress. Transcutaneous electrical nerve stimulation (TENS) applies a small electric current to certain parts of nerves, potentially interrupt pain signals and induce the release of endorphins. To be effective, use of TENS should be medically supervised.

Invasive procedures

Three types of invasive procedures may be used to manage or treat pain: anatomic, augmentative, and ablative. These procedures involve surgery, and certain guidelines should be followed before carrying out a procedure with permanent effects. First, the cause of the pain must be clearly identified. Next, surgery should be done only if noninvasive procedures are ineffective. Third, any psychological issues should be addressed. Finally, there should be a reasonable expectation of success.

Anatomic procedures involve correcting the injury or removing the cause of pain. Relatively common anatomic procedures are decompression surgeries, such as repairing a herniated disk in the lower back or relieving the nerve compression related to carpal tunnel syndrome. Another anatomic procedure is neurolysis, also called a nerve block, which involves destroying a portion of a peripheral nerve.

Augmentative procedures include electrical stimulation or direct application of drugs to the nerves that are transmitting the pain signals. Electrical stimulation works on the same principle as TENS. In this procedure, instead of applying the current across the skin, electrodes are implanted to stimulate peripheral nerves or nerves in the spinal cord.

Ablative procedures are characterized by severing a nerve and disconnecting it from the spinal cord.

Preparation

Prior to beginning management, pain is thoroughly evaluated. Pain scales or questionnaires are used to attach an objective measure to a subjective experience. Objective measurements allow healthcare workers a better understanding of the pain being experienced by the patient. Evaluation also includes physical examinations and diagnostic tests to determine underlying causes. Some evaluations require assessments from several viewpoints, including neurology, psychiatry, psychology, and physical therapy. If pain is due to a medical procedure, management consists of anticipating the type and intensity of associated pain and managing it preemptively.

Risks

Owing to toxicity over the long term, some drugs can only be used for acute pain or as adjuncts in chronic pain management. NSAIDs have the well-known side effect of causing gastrointestinal bleeding, and long-term use of acetaminophen has been linked to kidney and liver damage. Other drugs, especially narcotics, have serious side effects, such as constipation , drowsiness, and nausea . Serious side effects can also accompany pharmacological therapies; mood swings, confusion, bone thinning, cataract formation, increased blood pressure, and other problems may discourage or prevent use of some analgesics.

Nonpharmacological therapies carry little or no risk. However, it is advised that individuals recovering from serious illness or injury consult with their healthcare providers or physical therapists before making use of adjunct therapies. Invasive procedures carry risks similar to other surgical procedures, such as infection, reaction to anesthesia, iatrogenic (injury as a result of treatment) injury, and failure.

A traditional concern about narcotics use has been the risk of promoting addiction . As narcotic use continues over time, the body becomes accustomed to the drug and adjusts normal functions to accommodate to its presence. Therefore, to elicit the same level of action, it is necessary to increase dosage over time. As dosage increases, an individual may become physically dependent on narcotic drugs .

However, physical dependence is different from psychological addiction. Physical dependence is characterized by discomfort if drug administration suddenly stops, while psychological addiction is characterized by an overpowering craving for the drug for reasons other than pain relief. Psychological addiction is a very real and necessary concern in some instances, but it should not interfere with a genuine need for narcotic pain relief. However, caution must be taken with people with a history of addictive behavior.

Parental concerns

Infants feel pain, but do not express it in the same manner as older children or young adults. Studies indicate that the majority of parents do not know how to recognize the signs of infant pain, and pediatricians fail to teach parents what to look for. Training of parents is essential in recognizing and dealing with pain in infants and young children.

In some cases, narcotic analgesics are essential for control of childhood pain. These drugs are safe when used properly and should not be withheld for fear of addiction.

Because exposure to chronic pain by children can lead to life-long changes in their pain response, parents must learn to recognize and treat pain promptly.

Over-the-counter pain relievers may be toxic. Parents must read the labeled directions carefully and follow them exactly. For liquids, it is essential to use the proper measuring devices, such as a measuring dropper or medicinal teaspoon. Household measures are not reliable.

KEY TERMS

Acute —Refers to a disease or symptom that has a sudden onset and lasts a relatively short period of time.

Central nervous system —Part of the nervous system consisting of the brain, cranial nerves, and spinal cord. The brain is the center of higher processes, such as thought and emotion and is responsible for the coordination and control of bodily activities and the interpretation of information from the senses. The cranial nerves and spinal cord link the brain to the peripheral nervous system, that is the nerves present in the rest of body.

Chronic —Refers to a disease or condition that progresses slowly but persists or recurs over time.

Iatrogenic —A condition that is caused by the diagnostic procedures or treatments administered by medical professionals. Iatrogenic conditions may be caused by any number of things including contaminated medical instruments or devices, contaminated blood or implants, or contaminated air within the medical facility.

Neuropathy —A disease or abnormality of the peripheral nerves (the nerves outside the brain and spinal cord). Major symptoms include weakness, numbness, paralysis, or pain in the affected area.

Neurotransmitter —A chemical messenger that transmits an impulse from one nerve cell to the next.

Nociceptor —A nerve cell that is capable of sensing pain and transmitting a pain signal.

Nonpharmacological —Referring to therapy that does not involve drugs.

Peripheral nervous system (PNS) —The part of the nervous system that is outside the brain and spinal cord. Sensory, motor, and autonomic nerves are included. PNS nerves link the central nervous system with sensory organs, muscles, blood vessels, and glands.

Pharmacological —Referring to therapy that relies on drugs.

Stimulus —Anything capable of eliciting a response in an organism or a part of that organism.

See also Acetaminophen ; Nonsteroidal anti-inflammatory drugs .

Resources

PERIODICALS

Byers, J. F., and K. Thornley. "Cueing into infant pain." MCN American Journal of Maternal and Child Nursing 29, no. 2 (March-April 2004): 84–89.

Stinshoff V. J., et al. "Effect of sex and gender on drug-seeking behavior during invasive medical procedures." Academy of Radiology 11, no. 4 (April 2004: 390–397.

ORGANIZATIONS

American Chronic Pain Association. PO Box 850, Rocklin, CA 95677–0850. Web site: http://members.tripod.com/~widdy/ACPA.html.

American Pain Society. 4700 West Lake Ave., Glenview, IL 60025. Web site: http://www.ampainsoc.org.

WEB SITES

"Instructions for the Infant Pain Scale." Virtual Children's Hospital, Acute Pain Management for Pediatric Patients. Available online at <www.vh.org/pediatric/provider/pediatrics/PediatricPainMgmt/infantp inscale.html> (accessed on September 28, 2004).

"Riley Infant Pain Scale Assessment Tool." Cancer Pain Management in Children. Available at http://www.childcancerpain.org/content.cfm?content=assess09 (accessed September 28, 2004).

Julia Barrett Samuel Uretsky, PharmD



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