OVERVIEW ON

PAIN AND ITS

TRATMENT
Moh Hasan Machfoed
Department of Neurology
School of Medicine Airlangga University
Dr. Soetomo Hospital Surabaya
Mobil Phone: 0812-353-8163
E-mail: mhasanmachfoed@yahoo.com

DEFINITION OF PAIN

An unpleasant sensory
and emotional
experience associated
with actual or potential
tissue damage or
described in terms of
such damage
.

International
International Association for the Study of
Pain

TERMINOLOGIES
Agology the science and study of
pain
Allodynia pain caused by a stimulus
that is not normally painful
Analgesia the absence, or decrease,
of pain in the presence of a stimulus
that would normally be painful
Hyperalgesia an increased sensitivity
to a stimulus that is normally painful
Nociception the reception,
conduction, and central nervous
processing of nerve signals resulting
in the perception of pain
Somatic pain pain originating from
skin, joints, muscles, and other deep
tissues
Visceral pain pain originating from
the internal organs

TERMINOLOGIES
Noxious stimulus a stimulus which is actually
or potentially damaging to body tissues
Pain threshold the point at which an individual
just begins to feel pain; is relatively consistent
among normal individuals
Pain tolerance the greatest amount of pain that
a subject will tolerate; varies greatly among
individuals
Radiculalgia pain along the distribution of one
or more sensory nerve roots
Radiculitis an inflammation of one or more
nerve roots
Wind-up a cascade of events resulting from
ongoing stimulation of nociceptors and activation
of NMDA receptors; causes hyperalgesia and
opioid tolerance

TYPE OF SOMATIC SENSATIONS

Musculoskeletal
System

Skin

Temperature

Pain

Touch

Pressure

Proprioception

Position Sense

Vibration

Kinesthesia

Pain

TYPE OF PAIN
Physiological Pain

Pathological Pain

Is a protective
mechanism
Causes avoidance
Little to no tissue injury
Pain stops once the
stimulus is removed

Results from tissue

injury
Inflammation occurs in
the area
Nerve damage
Release of
neurotransmitters with
ongoing stimulation of
nociceptors
Can lead to
hyperalgesia
Persists after the
stimulus is removed

TYPE OF PAIN
Chronic Pain
Acute Pain
Occurs immediately after a
stimulus is received
Severity can vary
Responds well to treatment
Subsides once stimulus is
removed

Persists well past initial

stimulus (3-6 months)
Severity can vary
May or may not respond
well to treatment; may
require a multi-modal
approach
Can result in allodynia,
hyperalgesia, and opioid
tolerance

TYPE OF PAIN

TYPE OF PAIN
Referred Pain - pain that is perceived to
be in an area that seems to have little
relation to the existing pathology
Radiating Pain - pain caused by irritating
nerve roots and extending distally
Sclerotomic Pain - pain associated with a
segment of bone innervated by a spinal
segment that is a deep somatic pain

DIFFERENT
CHARACTERISTI
C AMONG PAIN
TYPES
10

Adopted
Adopted from
from Costigan
Costigan et
et al,
al, 2009
2009

Adopted
Adopted from
from Costigan
Costigan et
et al,
al, 2009
2009

12

Transmission/Perception of Pain

Four specific parts

of the nervous
system transmit
pain signals from
the periphery to the
higher centers of
the CNS:
the nociceptors,
the dorsal horn
neurons,
the ascending
tracts, and
the supraspinal
projections.

 Nociceptors, one type of

somatosensory
receptors, are the first
order neurons of pain
pathways.
Free nerve endings

These receptors
generate pain signals in
response to harmful
stimuli.
Different types of
nociceptors have been
identified that respond to

mechanical,
heat and
chemical stimuli, or
any combination of these
stimuli.

Nociceptors

Nociceptors

Cell bodies of the nociceptors reside in the dorsal root

ganglia (DRG).
Nerve fibers leaving the DRG bifurcate and send one branch
to the periphery and the other branch to the dorsal horn
(DH).
The peripheral fibers conduct pain signals from the skin,
muscles, fascia, vessels, and joint capsules to the DRG

Second Order Neurons

Two types of second order
neurons perceive pain:
nociceptive specific (NS) neurons
and
wide dynamic range (WDR)
neurons.

The NS and WDR neurons

conduct pain signals to the
brain via various ascending
tracts in the spinal cord.
NS respond to noxious stimuli
WDR respond to both
innocuous and noxious stimuli.
Axons of the second order
neurons (the NS and WDR
neurons) form the ascending
tracts, through which pain
signals travel in the spinal cord.

Robinson(1997), Journal of Hand Therapy

Mechanisms of Pain
Control
Gate control theory
Descending mechanisms(Central
Biasing)
Release of endogenous opioids (endorphin)
Pain relief may result from
combination of these 3 mechanisms

Descending pathways regulating

the transmission of pain
information:
intensity of pain varies among individuals
and depends on circumstances (i.e. soldier
wounded, athlete injured, during stress).
Stimulation of PAG causes analgesia so
profound that surgery can be performed.
PAG stimulation can ameliorate intractable
pain. PAG receives pain information via the
spinomesencephalic tract and inputs from
cortex and hypothalamus related to
behavioral states and to whether to activate
the pain control system. PAG acts on raphe
& locus ceruleus to inhibit dorsal horn
neurons via interneurons and morphine
receptors.

-Endorphin and
Dynorphin
Stimulation of A
and C afferents
can stimulate
release of
endogenous
opioid endorphin from
hypothalamus
Dynorphin
released from
periaqueductal

Dynorphin
released

Pain Sensitization
Peripheral sensitization to pain:

Mechanisms of early-onset
central sensitization:
Winduphomosynaptic activity-dependent
plasticity characterized by a progressive
increase in firing from dorsal horn neurons
during a train of repeated low-frequency Cfiber or nociceptor stimulation.
During stimulation, glutamate + substance P
+ CGRP elicit slow synaptic potentials
Windup results from the summation of these
slow synaptic potentials.
This produces a cumulative depolarization
that leads to removal of the voltagedependent Mg2+ channel blockade in
NMDA receptors and entry of Ca2+.
Increasing glutamate action progressively
increases the firing-response to each
individual stimulus

Centrally mediated hyperalgesia:

Under conditions of persistent injury, C fibers fire repetitively and the
response of dorsal horn neurons increase progressively (wind-up
phenomenon). This is due to activation of the N-methyl-D-aspartate
(NMDA)-type glutamate receptor and diffusion of substance P that
sensitizes adjacent neurons. Blocking NMDA receptors can block the
wind-up.
Noxious stimulation can produce these long-term
changes in
dorsal neurons excitability (central sensitization) which constitute a
memory of the C fiber input. Can lead to spontaneous pain and decreases
in the threshold for the production of pain.

Pain Assessment
Pain is a complex phenomenon which is
difficult to evaluate and quantify because it
is subjective
Thus obtaining an accurate and
standardized assessment of pain is
problematic

Pain Assessment

Pattern: onset & duration

Area: location
Intensity: level
Nature: description

Pain Assessment
P-Q-R-S-T format

Provocation How the injury occurred & what

activities the pain
Quality - characteristics of pain Aching
(impingement), Burning (n. irritation), Sharp
(acute injury), Radiating within dermatome
(pressure on n.)?
Referral/Radiation
Referred site distant to damaged tissue that
does not follow the course of a peripheral n.
Radiating follows peripheral n.; diffuse
Severity How bad is it? Pain scale
Timing When does it occur? p.m., a.m., before,
during, after activity, all the time

Pain Assessment Scales

Visual & Numeric Analog Scales
None
Severe
0
10
Locate area of pain on a pictures
McGill pain questionnaire
Evaluate sensory, evaluative, &
affective components of pain
20 subcategories, 78 words

Visual Analogue Scales

Scales are quick and simple tests

Consist of a line, usually 10 cm in length,
the extremes of which are taken to
represent the limits of the pain experience.
Scales can be completed daily or more
often

Numeric Pain Scale

Most common
Patient is asked to rate pain on a scale
from 1 to 10
Pre- to Post-treatment
When treatments provide pain relief
patients are asked about the extent and
duration of the relief

Goals In Managing Pain

To control acute pain and protect
patient from further injury while
encouraging progressive exercise in a
supervised environment
Reducing pain is an essential part of
treatment

Principles of Pain
Management

Treatment of Intractable
Pain
Treat the underlying disease
nonnarcotic analgesics and
antidepressants or anticonvulsants
narcotics
local nerve blocks

Non-steroidal Antiinflammatory Drugs (NSAIDs)

NSAIDs are weak organic acids with antiinflammatory, analgesic, and antipyretic
properties
Inhibit prostaglandin production by inhibiting
COX enzymes
Are either non-selective (inhibits both COX isoenzymes) or selective for COX-2
Non-selective NSAIDs have more serious side
effects (gastric ulceration and renal toxicity)
Decreased renal blood flow during anesthesia
makes kidneys more susceptible to toxic
effects

Non-drug Treatments (1)

Nerve Blocks
Local Anaesthetic
Neurolytic (phenol)

Neurosurgery
Cordotomy

Immobilisation
Rest / Slings /Splints/ Corset
Walking Aids / Wheelchair

Non-drug Treatments (2)

Psychology
Individual
Group
Relaxation
Education
Cognitive Therapy
Multi-disciplinary Approach

Distraction
Hypnosis

Non-drug Treatments (3)

Counter-irritation
Massage Gate Control Theory
TENS Gate Control Theory
Acupuncture stimulates release of
endorphins

Physical
Exercise and mobility
Physiotherapy
Hydrotherapy
Music/ Art therapy

Lifestyle Modification

CBT
Cognitive Behaviour Therapy

Physical
Pain

Neuropathic Pain
Management

Neuropathic Pain
Pharmacological
Invasive/injection therapy
Physical therapies
Psychological therapy
Complementary therapy

WHO Ladder +/- NSAIDs

Compound analgesics
Nsaids- use for trial of 3-7 days and
then review
Opioids do work
No evidence for one opioid above
another except Methadone

Anti-depressants
Best evidence base is amitriptylline
Usually well tolerated
Rapid response
1 wk to reach steady state

Anti-convulsants
Gabapentin

Short acting
Safe/ Good side-effect profile
Can use in severe renal compromise
Memory loss and reduced concentration
More expensive
Improved sleep pattern
Mood enhancement

Clonazepam good for night pain

Methadone - Indications for use

Intolerable side-effects with other opioids
Inadequate analgesia despite dose
titration
Morphine hyperexcitability, allodynia
Morphine poorly responsive pain
Nociceptive & Neuropathic pain
Antitussive

MATUR
NUWUN
MHM 24-11-2015

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