DEFINITION OF PAIN
Pain, while complex, seems too
obvious a human experience
to attempt a verbal definition but
the International Association
for the Study of Pain (IASP)
has nevertheless, after much
debate, research and deliberation
reduced pain to the following
definition:
Pain:
"An unpleasant sensory and emotional
experience associated with actual
or potential tissue damage, or
described in terms of such damage"
This accepted definition suggests
a bridge between physical and
psychological generators of the
pain experience. The work of
Crue and associates (1979, 1980,
2004) and others conceptualize
pain as an interpretation of
the meaning of signals coming
from the body's periphery. In
their view pain is not a primary
sensation. It is an interpretation
of activity coming from the sensory
receptors (vision, hearing, taste,
smell, touch, pressure, temperature,
proprioception).
Early life experiences of a subjective
nature provide the learning basis
of pain which can shape and form
our later reactions to pain.
Melzack and Wall (1965) found
that pain perception involves
three different systems:
- Sensory-discriminative
- Motivational-affective
- Cognitive-evaluative
Known as the "Gate-Control Theory",
it integrates peripheral stimuli
with brain/spinal cord mechanisms.
Thus, incoming stimulation from
sensations (ie., temperature,
pressure, etc. receptors) in
the body are processed in the
brain and spinal cord which determines
whether the sensation is determined
to be "painful" or not. Important
to the theory is the idea that
the brain and all its functions
including confidence, memory,
anxiety, depression to name a
few, exerts a downward influence
on incoming sensations. It can "dampen" or
even entirely stop the upward
flow of strong sensations. It
can also reinterpret the arriving
sensations in ways that changes
the experience. From "excruciating" to "annoying" or
from "agonizing" to "irritating" or
the reverse!
The work of Crue, Melzack and
others forms a neurophysiologic
basis for explaining the development
of some persistent chronic pain
syndromes. Also, known as "central
pain disorders", they have been
shown to be improved with treatment
methods used in chronic pain
management programs. These treatments
are designed to strengthen the
functioning of the brain and
spinal cord. This includes chemical,
mental, emotional and physical
functions.
At Pacifica Pain Management Services
we have adapted existing definitions
with our clinical experience
to formulate the following definition
of a chronic pain syndrome:
Chronic
Pain Syndrome:
An unpleasant sensory
or emotional experience associated
with actual or potential
tissue damage which has lasted
for at least 6 months and
has not responded to aggressive
medical pain management efforts.
It has resulted in a cluster
of problems (syndrome) such
as weight gain, narcotic
dependency/abuse/addiction,
depression, muscle wasting,
sexual dysfunction, secondary
physical problems (ie., gastric
distress, bowel dysfunction),
insomnia, social withdrawal,
etc. The syndrome interacts
with pain to create a complex
that is difficult to treat.
It is frequently confused
with a primary psychological
disorder which it is not.
Selected Definitions:
Pain: "An
unpleasant sensory and emotional
experience associated with
actual or potential tissue
damage, or described in terms
of such damage" - International
Association for the Study
of Pain (1994)
Acute
pain is the normal,
predicted physiological response
to an adverse chemical, thermal,
or mechanical stimulus associated
with surgery, trauma, and
acute illness. It is usually
of recent onset and generally
time-limited
Hyperesthesia: reduced
reaction to a noxious or
aversive stimulus.
Hyperalgesia: excessive
pain response.
Paresthesia: an
abnormal sensation which
is not perceived as painful
but perhaps as tingling or
pins and needles.
Dysesthesia is
a strong sensation which
is perceived as unpleasant
or painful.
Allodynia is
pain produced by a stimulus
which would not normally
cause pain.
Tolerance
(drug) is a physiologic
state resulting from regular
use of a drug in which an
increased dosage is needed
over time to produce the
same effect, or a reduced
effect is observed with a
constant dose.
Physical
dependence (drug): a
physiologic state marked
by the emergence of a withdrawal
syndrome if drug use is stopped/decreased
abruptly, or if an antagonist
is administered. Physical
dependence usually occurs
with use of narcotics. By
itself, it does not necessarily
equate with addiction.
Addiction is
a neurobehavioral syndrome
with genetic and environmental
influences that results in
psychological dependence
on the use of substances
for their psychic and physical
effects and is characterized
by compulsive use despite
harm. Addiction may also
be referred to by terms such
as "drug dependence" and "psychological
dependence". Physical dependence
and tolerance are expected
physiological consequences
of extended narcotic therapy
for pain and are also part
of the addiction process.
Pseudo-addiction is
a confusing term regarding
drug seeking behavior in
pain patients who are receiving
inadequate pain management
that can be mistaken for
addiction. The term can be
used by physicians and patients
alike to deny the truth of
their behavior (ie., co-dependent
and addictive). Probably
a term of little value.
Substance
abuse is the use of
any substance(s)/drugs for
non-therapeutic purposes
or use of medication for
purposes other than those
for which it is prescribed.
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