Table of Contents
Definition
Pain management encompasses pharmacological,
nonpharmacological, and other approaches to prevent,
reduce, or stop pain sensations.
Top of Page
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. After the
message is received and interpreted, further pain can be
counter-productive. 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 an individual's quality of
life.
Top of Page
Description
What is pain?
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.
A pain message is transmitted to the CNS by special
PNS nerve cells called nociceptors. Nociceptors 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
sensations such 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 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. 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 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. It
usually resolves once the condition that precipitated it
is resolved.
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 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 regular
nociceptive pain.
It has been hypothesized that uninterrupted and
unrelenting pain can induce changes in the spinal cord.
In the past, intractable pain has been treated by
severing a nerve's connection to the CNS. 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.
Top of Page
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 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.
Top of Page
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 the 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 its ability to reduce inflammation is limited.
NSAIDs and acetaminophen are effective for most forms
of acute (sharp, but of a short course) 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 are
classified as either opiates or opioids, and are
available only with a doctor's prescription. Opiates
include morphine and codeine, which are derived from
opium, a substance naturally found in some poppy
species. Opioids are synthetic drugs based on the
structure of opium. This drug class includes drugs such
as oxycodone, methadone, and meperidine
(Demerol).
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.
Top of Page
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
interrupting pain signals and inducing release of
endorphins. To be effective, use of TENS should be
medically supervised.
Top of Page
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.
Top of Page
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 health care 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
and 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.
Top of Page
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 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, 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.
Top of Page
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.
Top of Page
Key Terms
- Acute
-
Referring to pain in response to injury or
other stimulus that resolves when the injury
heals or the stimulus is removed.
- Chronic
-
Referring to pain that endures beyond the
term of an injury or painful stimulus. Can
also refer to cancer pain, pain from a
chronic or degenerative disease, and pain
from an unidentified cause.
- CNS or
central nervous system
-
The part of the nervous system that includes
the brain and the spinal cord.
- Iatrogenic
-
Resulting from the activity of the
physician.
- Neuropathy
-
Nerve damage.
-
Neurotransmitter
-
Chemicals within the nervous system that
transmit information from or between nerve
cells.
- Nociceptor
-
A nerve cell that is capable of sensing pain
and transmitting a pain signal.
-
Nonpharmacological
-
Referring to therapy that does not involve
drugs.
-
Pharmacological
-
Referring to therapy that relies on drugs.
- PNS or
peripheral nervous system
-
Nerves that are outside of the brain and
spinal cord.
- Stimulus
-
A factor capable of eliciting a response in
a nerve.
Top
of Page
