Pain management - non technical article

Definition

Pain itself is defined by the International Association for the Study of Pain (IASP) as ‘‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.’’ Thus, pain management encompasses all interventions used to understand and ease pain, and if possible to alleviate the cause of the pain.

Purpose

Pain serves to alert a person to potential or actual damage to the body. The definition of damage is quite broad: pain can arise from injury as well as disease. After the message is received and interpreted, further pain can be counterproductive. Pain can have a negative impact on a person’s quality of life and impede recovery from illness or injury, thus contributing to escalating health care costs. Unrelieved pain can become a syndrome in its own right and cause a downward spiral in a person’s health and emotional outlook. Managing pain properly facilitates recovery, prevents additional health complications, and improves an individual’s quality of life.

Yet the experiencing of pain is a completely unique occurrence for each person, a complex combination of several factors other than the pain itself. It is influenced by:

• Ethnic and cultural values. In some cultures, tolerating pain is related to showing strength and endurance. In others, pain is considered punishment for misdeeds.
• Age. Many people have been taught that grownups never cry. On the other hand, in some cultures, the elderly are allowed to complain freely about pain and discomfort.
• Anxiety and stress. This factor is related to being in a strange or unfamiliar place such as a hospital, and the fear of the unknown consequences of the pain and the condition causing it, which can all combined to make pain feel more severe. For patients being treated for pain, knowing the duration of activity of an analgesic leads to anxiety about the return of pain when the drug wears off. This anxiety can make the pain more severe. In addition, patients who interpret their pain as meaning that their disease is recurring or getting worse often experience pain as more severe. Fatigue and depression. It is known that pain in itself can actually cause emotional depression.
• Fatigue from lack of sleep or the illness itself also contributes to depressed feelings.

Precautions

The perception of pain is an individual experience. Healthcare providers play an important role in understanding their patients’ pain. All too often, both physicians and nurses have been found to incorrectly assess the severity of pain. A study reported in the Journal of Advanced Nursing evaluated nurses’ perceptions of a select group of white American and Mexican-American women patients’ pain following gallbladder surgery. Objective assessments of each patient’s pain showed little difference between the perceived severities for each group. Yet, the nurses involved in the study consistently rated all patients’ pain as less than the patients reported, and with equal consistency, believed that better-educated women born in the United States were suffering more than less-educated Mexican-American women. Nurses from a northern European background were more apt to minimize the severity of pain than nurses from eastern and southern Europe or Africa. The study indicated how healthcare staff, and especially nursing staff, need to be aware of how their own background and experience contributes to how they perceive a person’s pain.

Some patient populations are particularly susceptible to inadequate pain management. These include cancer patients; children; trauma victims receiving treatment in hospital emergency departments; and the elderly in nursing homes.

Description

Before considering pain management, a review of pain definitions and mechanisms may be useful. 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. Pain is sometimes categorized by its site of origin, either cutaneous (originating in the skin, or subcutaneous tissue, such as a shaving nick or paper cut), deep somatic pain (arising from bone, ligaments and tendons, nerves, or veins and arteries), or visceral (appearing as a result of stimulation of pain receptor nerves around such organs as the brain, lungs, or stomach and intestines).

A pain message is transmitted to the CNS by special PNS nerve cells called nociceptors, which are distributed throughout the body and respond to different stimuli depending on their location. For example, nociceptors that extend from the skin are stimulated by such sensations as pressure, temperature, and chemical changes.

When a nociceptor is stimulated, neurotransmitters are released within the cell. Neurotransmitters are chemicals found within the nervous system that facilitate nerve cell communication. The nociceptor transmits its signal to nerve cells within the spinal cord, which conveys the pain message to the thalamus, a specific region in the brain.

Once the brain has received and processed the pain message and coordinated an appropriate response, pain has served its purpose. The body uses natural painkillers called endorphins to derail further pain messages from the same source. However, these natural painkillers may not adequately dampen a continuing pain message. Also, depending on how the brain has processed the pain information, certain hormones such as prostaglandins may be released. These hormones enhance the pain message and play a role in immune system responses to injury, such as inflammation. Certain neurotransmitters, especially substance P and calcitonin gene-related peptide, actively enhance the pain message at the injury site and within the spinal cord.

Pain is generally divided into two additional categories: acute and chronic. 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. Response to acute pain is made by the sympathetic nervous system (the nerves responsible for the fightor- flight response of the body). It normally resolves once the condition that precipitated it is resolved.

There are some disorders that produce pain that does not resolve following the disorder. Even after healing or a cure has been achieved, the brain continues to perceive pain. In this situation, the pain may be considered chronic. Chronic pain is within the province of the parasympathetic nervous system, and the changeover occurs as the body attempts to adapt to the pain. 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 chronic pain as pain that 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, unremitting pain that lacks an identifiable physical cause such as the majority of cases of low back pain may be considered chronic. The underlying biochemistry of chronic pain appears to be different from that of acute nociceptive pain.

It has been hypothesized that uninterrupted and unrelenting pain can induce changes in the spinal cord. In the past, severing a nerve’s connection to the CNS has treated intractable pain. However, the lack of any sensory information being relayed by that nerve can cause pain transmission in the spinal cord to go into overdrive, as evidenced by the phantom limb pain experienced by amputees. Evidence is 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. Immune chemicals, primarily cytokines, may play a prominent role in such changes.

Managing pain

Considering the different causes and types of pain, as well as its nature and intensity, management usually requires a multidisciplinary approach. The elements of this approach include treating the underlying cause of pain, pharmacological and non-pharmacological therapies, and some invasive (surgical) procedures. Treating the cause of pain underlies the basic strategy of pain management. Injuries are repaired, diseases are diagnosed, and certain encounters with pain can be anticipated and treated prophylactically (by prevention). However, there are no guarantees of immediate relief from pain. Recovery can be impeded by pain and quality of life can be damaged. Therefore, pharmacological and other therapies have developed over time to address these aspects of disease and injury.

Pharmacological options

General guidelines developed by the World Health Organization (WHO) have been developed for pain management. These guidelines operate upon the three-step ladder approach, including:

• Mild pain is alleviated with acetaminophen or a nonsteroidal anti-inflammatory drug (NSAID). NSAIDs and acetaminophen are available as overthe- counter (OTC) and prescription medications, and are frequently the initial pharmacological treatment for pain. These drugs can also be used as adjuncts to the other drug therapies that 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 painenhancing neurotransmitters. Acetaminophen is also effective against pain, but its ability to reduce inflammation is limited. NSAIDs and acetaminophen are effective for most forms of acute (sharp, but of a short duration) pain.
• Mild to moderate pain is eased with a milder opioid medication, plus acetaminophen or NSAIDs. Opioids include both drugs derived from the opium poppy, such as morphine and codeine, and synthetic drugs based on the structure of opium. This drug class includes drugs such as oxycodone, methadone, and meperidine (Demerol). They provide pain relief by binding to specific opioid receptors in the brain and spinal cord. One drawback of opioids, however, is that they frequently cause constipation because they slow down the rhythmic muscular contractions of the intestines that push food along during the process of digestion.
• Moderate to severe pain is treated with stronger opioid drugs, plus acetaminophen or NSAIDs. Morphine is sometimes referred to as the gold standard of palliative care as it is not expensive; can be given by starting with smaller doses and gradually increased; and is highly effective over a long period of time. It can also be given by a number of different routes, including by mouth, rectally, or by injection.

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.

In some cases, chronic pain caused by complications of diabetes or cancer can be eased by administering local anesthetics. The most commonly used are mexiletine (Mexitil) and a lidocaine patch.

Corticosteroids are another class of drugs commonly given to manage chronic pain caused by arthritis or other diseases affecting the muscles and joints; they may also be given to control nausea. Dexamethasone (Decadron) and prednisone are the most commonly used corticosteroids in pain management. They work by reducing inflammation and suppressing the immune system.

Close monitoring of the effects of pain medications is required in order to assure that adequate amounts of medication are given to produce the desired pain relief. When a person is comfortable with a certain dosage of medication, oncologists typically convert to a long-acting version of that medication. Transdermal fentanyl patches (Duragesic) are a common example of a long-acting opioid drug often used for cancer pain management. A patch containing the drug is applied to the skin and continues to deliver the drug to the person for an average of three days. Pumps are also available that provide an opioid medication upon demand when the person is experiencing pain. By pressing a button, they can release a set dose of medication into an intravenous solution or an implanted catheter. Another mode of administration involves implanted catheters that deliver pain medication directly to the spinal cord. Because these pumps offer the patient some degree of control over the amount of analgesic administered, the system, commonly called patient-controlled analgesia (PCA), reduces the level of anxiety about availability of pain medication. Delivering drugs in this way can reduce side effects and increase the effectiveness of the drug. Research is underway to develop toxic substances that act selectively on nerve cells that carry pain messages to the brain. These substances would kill the selected cells and stop transmission of the pain message.

Non pharmacological 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 nondrug therapies is that an individual can take a more active role in pain management. Such relaxation techniques as yoga and meditation are used to focus the brain elsewhere than on the pain, 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.

Hypnosis is another nonpharmacological option for pain relief. Although doctors do not yet fully understand how hypnosis works, it is used successfully in some patients to manage pain related to childbirth, oral surgery, burn treatment, and other procedures that require the patient to remain conscious. 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 painkillers. 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 interrupting pain signals and inducing release of endorphins. To be effective, use of TENS should be medically supervised.

Invasive procedures 

There are three types of invasive procedures that 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.

Augmentative procedures also include implanted drug-delivery systems. In these systems, catheters are implanted in the spine to allow direct delivery of drugs to the CNS.

Ablative procedures are characterized by severing a nerve and disconnecting it from the CNS. However, this method may not address potential alterations within the spinal cord. These changes perpetuate pain messages and do not cease, even when the connection between the sensory nerve and the CNS is severed. With growing understanding of neuropathic pain and development of less invasive procedures, ablative procedures are used less frequently. However, they do have applications in select cases of peripheral neuropathy, cancer pain, and other disorders.

Preparation

Prior to beginning management, the patient’s pain should be thoroughly evaluated, including a psychosocial as well as a physical assessment. Pain scales or questionnaires can be administered by a member of the healthcare team, although there is no single questionnaire that is universally accepted. Some questionnaires are verbal, while others use pictures or drawings to help the patient describe the pain. Some questionnaires are filled out by the patient, while others may be given to relatives or friends to complete. It is often necessary to ask other family members to complete a pain questionnaire if the patient is cognitively impaired.

In spite of their limitations, questionnaires and self-report forms do allow healthcare workers to better understand the pain being suffered by the patient. Evaluation also includes physical examinations and diagnostic tests to determine the underlying physical causes of the pain. Some evaluations require assessments from several viewpoints, including neurology, psychiatry and psychology, and physical therapy. If the pain is caused by a medical procedure, management consists of anticipating the type and intensity of associated pain and managing it preemptively.

Nurses or physicians often take what is called a pain history. This history will help to provide important information that can help health care providers to better manage the patient’s pain. A typical pain history includes the following questions:

• Where is the pain located?  
• On a scale of 1 to 10, with 1 indicating the least pain, how would the person rate the pain being experienced?
• What does the pain feel like?
• When did (or does) the pain start?
• How long has the person had it?
• Is the person sometimes free of pain?
• Is the pain constant, or is it episodic?
• Does the person know of anything that triggers the pain or makes it worse?
• Does the person have other symptoms (nausea, dizziness, blurred vision, etc.) during or after the pain?
• What pain medications or other measures has the person found to help in easing the pain?
• How does the pain affect the person’s ability to carry on normal activities?
• What does it mean to the person that he or she is experiencing pain?

Aftercare

An assessment by nursing staff as well as other healthcare providers should be made to determine the effectiveness of the pain management interventions employed. There are objective, measurable signs and symptoms of pain that can be looked for. The goal of good pain management is the absence of these signs. Signs of acute pain include:

• rise in pulse and blood pressure
• more rapid breathing
• perspiring profusely, clammy skin
• taut muscles
• more tense appearance, fast speech, very alert
• unusually pale skin
• dilated pupils of the eye

Signs of chronic pain include:

• lower pulse and blood pressure
• changeable breathing pattern
• warm, dry skin nausea and vomiting
• slow or monotone speech
• inability or difficulty in getting out of bed and performing activities of daily living (ADLs)
• constricted pupils of the eye

When these signs are absent and the patient appears to be comfortable, healthcare providers can consider their interventions to have been successful. It is also important to document interventions used, and which ones were successful.

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 wellknown 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 such serious side effects 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 risks. However, individuals recovering from serious illness or injury should consult with the health care 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, and iatrogenic (injury as a result of treatment) injury.

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 who have a history of addictive behavior.

Normal results

Effective application of pain management techniques reduces or eliminates acute or chronic pain. This treatment can improve an individual’s quality of life and aid in recovery from injury and disease.