Assessing pain in primary care

Abstract

Pain is one of the the most common symptoms with which patients present in primary care. Before pain can be managed, its severity and nature need to be understood. The nature of pain is important, as a good clinical history will guide further investigation, leading to diagnosis. Monitoring pain severity is critical, as pain is largely a subjective experience, which cannot be properly managed if worsening or improvement is not monitored from a baseline. Using a standard pain measurement tool will allow for pain management over time, as the response to analgesics can be properly monitored. Different tools, to allow practitioners to assess pain in any setting, are available for patients of all ages.

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CPD Article:
Assessing pain in primary care
21 Vol 54 No 1S Afr Fam Pract 2012
Divinum est opus seclare dolorem. (Divine is the work to
subdue pain).
Introduction
Acute and chronic pain is the most common, and yet most
poorly understood and managed medical complaint. While
the pathophysiology of acute pain is well understood, the
effect of pain on current and future perception of pain
(whether acute or chronic), is inuenced by a range of
psychological, biological, hormonal, and cognitive factors.
Pain is a perception, rather than just a symptom, and
varies widely between individuals, regardless of the cause.
Effective management of pain is a health practitioner’s
primary moral obligation. To achieve this, an ability to
understand the causes, severity, type, and progress, of the
pain, over time, is required.
Multiple tools can be used to assess pain in everyday
practice. Finding a suitable approach improves the overall
understanding of pain, and ensures that patients are
afforded optimal pain intervention, according to their needs.
Why assess pain?
Pain is very common and can be debilitating. Despite
advances in health care, chronic pain remains one of the
most common, ongoing symptoms, and is a leading cause
of disability worldwide.
1
The World Health Organization
(WHO) estimates that one in ve people suffer from
moderate-to-severe chronic pain, and that one in three
people are unable, or less able, to maintain an independent
lifestyle, due to their pain.
2

Leading pain complaints are back pain (27%), headaches
and migraines (15%), neck pain (15%), and facial aches
and pains (4%).
1
The American Medical Association (AMA)
estimates that 42% of people experience pain daily.
3
Despite these staggering statistics, frequently, pain remains
unrecognised and undertreated by most physicians.
4,5
Pain is all about perception
The International Association for the Study of Pain (IASP)
denes pain as “an unpleasant sensory and emotional
experience, associated with actual, or potential, tissue
damage, or described in terms of such damage”.
3
Pain is
a subjective perception, and not a sensation. This means
that there is no way to objectively quantify it. Consequently,
an assessment of a patient’s pain depends on the patient’s
overt communication.
6
Just talking to your patient is not enough
Physicians tend to either rely on patients voluntarily vocalising
the severity of their pain, or expect to identify obvious non-
verbal cues during the consultation. Unfortunately, both
of these are highly unreliable measures, as there is wide
variability in the expression of pain. Physicians who do not
use formal pain assessment tools will miss severe pain in
30% of patients, and moderate pain in half of all patients.
7
Untreated pain causes long-term
consequences
There is increasing recognition that, even acute pain left
untreated for relatively short time periods, leads to neuronal
Assessing pain in primary care
Koch K, MbCHB
Private Practice General Practitioner and Freelance Medical Writer
Correspondence to: Karen Koch, e-mail: karenk@vodamail.co.za
Keywords: pain, assessment, chronic pain, acute pain, visual analogue scale
Abstract
Pain is one of the the most common symptoms with which patients present in primary care. Before pain can be managed,
its severity and nature need to be understood. The nature of pain is important, as a good clinical history will guide further
investigation, leading to diagnosis. Monitoring pain severity is critical, as pain is largely a subjective experience, which cannot
be properly managed if worsening or improvement is not monitored from a baseline. Using a standard pain measurement
tool will allow for pain management over time, as the response to analgesics can be properly monitored. Different tools, to
allow practitioners to assess pain in any setting, are available for patients of all ages.
© Medpharm S Afr Fam Pract 2012;54(1):21-24

CPD Article:
Assessing pain in primary care
22 Vol 54 No 1S Afr Fam Pract 2012
modelling and central sensitisation, as pain imprints itself
within the brain.
8
Repeated peripheral pain stimulation leads
to a progressive build-up of an electrical response in the
central nervous system, leading to intensied stimulation
of the nerve bres. This is why acute pain may persist to
become chronic pain, long after the initiating event has
subsided.
9
Medical professionals have a duty to
manage pain
According to the WHO, access to pain management is a
fundamental human right, articulated in all the foundation
covenants of the United Nations.
10
The Health Professions
Council of South Africa’s (HPCSA) general guidelines for
health professionals refers to pain alleviation as a “moral
obligation” of licensed professionals.
11
Pain assessment
Goals12
• To capture the individual’s pain experience in a
standardised way
• To help determine type of pain, and possible aetiology
• To determine the effect, and impact, the pain experience
has on the individual, and his or her ability to function
• To have a basis on which to develop a treatment plan to
manage pain
• To aid communication between interdisciplinary team
members.
Principles
• Pain, especially chronic pain, is a complex condition. An
assessment requires a biopsychosocial approach to fully
understand the patient’s condition.
8
Table I: Pain assessment using the acronym “O, P, Q, R, S, T, U and V”13
OOnset When did it begin? For how long does it last? How often does it occur?
PProvoking and palliating What brings it on? What makes it better? What makes it worse?
QQuality What does it feel like? Can you describe it?
RRegion or radiation Where is it? Does it spread anywhere?
SSeverity What is the intensity of this symptom? (Use a grading from 0-10, a visual analogue scale, or facial expression
scale). Right now? At best? At worst? On average? How bothered are you by this symptom? Are there any other
symptoms that accompany this symptom?
TTreatment What medications and treatments are you currently using? How effective are these? Are there any side-effects
from the medications and treatments? What medications and treatments have you used in the past?
UUnderstand how it
impacts on you
What do you believe is causing this symptom?
How is this symptom affecting you and your family?
VValues What is your goal for this symptom? What is your comfort goal or acceptable level for this symptom? (On a
scale of 0-10, with 0 being none, and 10 being the worst possible). Are there any other views or feelings about
this symptom that are important to you, or your family?
Figure 1: Unidimensional rating scales

CPD Article:
Assessing pain in primary care
23 Vol 54 No 1S Afr Fam Pract 2012
• Pain may not always correlate with an identiable source
of injury.
3
• Believe what the patient is reporting to be true. Believing
that they are in pain does not necessarily equate having
to identify the source, or to prescribe certain treatments.
Acknowledgement is often all that patients seek.
3
Taking a detailed history
The letters “O, P, Q, R, S, T, U and V” provides a useful
memory aid, when taking your patient’s pain history (Table I).
13
Understanding pain intensity
Quantifying pain intensity is an essential part of both the
initial, and follow-up, process, in pain treatment. There are
several methods of doing so. The choice of method often
depends on the age, cognitive capacity, and communication
restrictions, of the patient. To optimise management, it
is important to consistently apply the same assessment
model to an individual over time.
3
Unidimensional pain scales
The most commonly used unidimensional rating scales are
shown in Figure 1.
3
Verbal rating scale
The verbal rating scale (VRS) is the most simple pain
measurement scale. It literally translates to asking the
patient if the pain is “mild,” “moderate,” or “severe.”
3
Numeric rating scale
The numeric rating scale (NRS) is slightly more
complex. Ask the patient to rate his or her pain between
0 (no pain) and 10 (worst pain imaginable). This is a useful,
ongoing tool that can be used when asking a patient to
monitor his or her pain throughout the day, or at different
follow-up sessions. It is also a useful tool for understanding
pain patterns and modiers.
14
Visual analogue scale
The visual analogue scale (VAS) is similar to the numeric
rating scale, except that patients simply point on the line as
to how severe their pain is (between “no pain” and “worst
pain imaginable”). The point, or mark, made by the patient is
recorded in millimetres. The advantage is that this does not
limit the patient to 10 distinct numbers.
3
FACES pain scale
The FACES scale is a visual facial expression representation
of both the numerical and visual analogue scale. The faces
range from “happy” to “severe pain” in six to eight different
faces. This scale is particularly useful for small children,
or for patients with whom the language barrier may be an
issue.
15
Multidimensional pain scales
More complex pain scales take into account the location of
the pain, the mood of the patient, and functionality.
These are useful tools in patients with highly resistant
chronic pain, where subtle management changes are likely
to change pain outcomes.
3
Pain classification
Functionally, pain is divided into “acute” and “chronic” pain.
Both are due to different physiological mechanisms, and
therefore require different modalities of treatment.
Acute pain
Acute pain is generally dened as “normal biological pain”
which occurs in response to painful (noxious) stimuli. It
usually indicates underlying tissue damage, or trauma.
It is a useful symptom which alerts the patient, and the
practitioner, to the presence of an underlying pathology.
16,17
Acute pain stimulates the sympathetic nervous system,
resulting in “ght” or “ight” response symptoms, including
increased heart and respiratory rates, sweating, dilated
pupils, restlessness and apprehension.
Acute pain is usually classied as “visceral” or “somatic”,
depending on the origin,
18
e.g. pancreatitis is a visceral
source of pain, while a skin wound would be somatic.
Mechanism of action
Activation via the normal pain pathway occurs through
the nociceptors, or pain receptors. These are free nerve
endings that respond to painful stimuli found throughout the
body. They are stimulated by biological, electrical, thermal,
mechanical and chemical stimuli.
Pain perception occurs when these stimuli are transmitted
to the spinal cord, and then to the central areas of the brain.
Pain impulses travel to the dorsal horn of the spine, where
they synapse with dorsal horn neurons in the substantial
gelatinosa, and then ascend to the brain. The basic
sensation of pain occurs at the thalamus. It continues to the
limbic system (emotional centre) and the cerebral cortex,
where pain is perceived and interpreted.
8
Pain modication occurs at various points in this
transduction process. The actual sensation of pain is a
result of numerous integrated inputs, processed by the
brain’s “pain matrix”.
8
Modulators of acute pain
At the site of the injury or stimulus, pain continues to be
activated by chemical mediators such as histamine,
substance P, bradykinin, acetylcholine, leukotrienes and
prostaglandins, which also potentiate inammation.
19

CPD Article:
Assessing pain in primary care
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The body also has a built-in chemical mechanism to manage
pain. Fibres in the dorsal horn, brain stem, and peripheral
tissues release neuromodulators, known as endogenous
opioids, which inhibit the action of neurons that transmit
pain impulses, causing natural pain relief.
20
Chronic pain
The IASP has dened chronic pain as “pain that persists for
longer than the time expected for healing (usually taken to
be three months), or pain associated with progressive, non-
malignant disease”.
21
The term “chronic” is still widely used, although many
pain experts now think of it as different subtypes, such as
“neuropathic”, “intermittent”, or “continuous.”
Mechanism of action
Chronic pain is poorly understood, and is more complex
and difcult to manage than acute pain. Persistent pain can
be caused by ongoing nocioreceptor stimulation, such as
that which occurs in chronic inammatory conditions, e.g.
rheumatoid arthritis.
3
Usually, however, by the time chronic pain occurs, the
original pathology which gave rise to the pain is no longer
present. Instead, sensitisation of the central nervous system
and neural pathways has occurred through repeated pain
exposure, as well as the inuence of psychosocial factors.
6
Some evidence indicates that chronic pain and depression
share the same physiological pathway.
22,23
Neuropathic pain is a particular form of chronic pain, in
which abnormal changes in the peripheral nerves, e.g.
diabetes-related damage, or central nervous system
dysfunction, leads to the experience of ongoing burning,
shock-like or tingling pain.
24
Conclusion
Pain, both acute and persistent, is frequently encountered in
general practice. Unfortunately, without proper assessment,
pain remains undiagnosed and untreated. Pain is a per-
ception, rather than a symptom, and requires patient-
interaction to understand it.
While treating the underlying cause of pain is imperative in
the acute treatment strategy, if left untreated, pain itself can
become a condition. Mechanisms which alter pain sensitivity
are affected by the presence of frequent, or untreated, pain
episodes, but also by a range of psychosocial factors, in a
manner that is poorly understood.
The overall processing of the perception of pain within the
central nervous system results in complex, intractable pain
syndromes, which can cause signicant ongoing morbidity
and disability.
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