Pain management

PainManagement
8/22/2021 CompiledBy:DanielM 1
1
If we know that pain and suffering can be alleviated, and do
nothing about it, then we ourselves, become the tormentors.
—Primo Levi

Session outline
Introduction
Pathophysiology
Pain classification
Clinical presentation
Treatment
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Introduction
Pain is: "an unpleasant sensory and emotionalexperience
associated with actual or potentialtissue damage.
Today, pain's impact on society still is great, and indeed
pain complaints remain a primary reason patients seek
medical advice.
Humans have always known and sought relieffrom pain.
However, as pain is subjective, many clinicians define
pain as “whatever the patient says it is.”
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EPIDEMIOLOGY
Data presented in the Institute of Medicine report, “Relieving
Pain in America” suggests that greater than 100 million
persons in the United States live with chronic pain.
Given that greater than 50% of persons reporting low back
pain in the previous 3 months
it is not surprising that the estimated economic burden of
chronic pain alone exceeds 500 billion dollars (US) annually.
Unfortunately, despite much public attention, pain often
remains inadequately or inappropriately treated.
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Compiled By: Daniel M

TypesofPain
Nociceptive pain
Nociceptive pain typically is classified as either:
Somatic pain
 Pain arising from skin, bone, joint, muscle, or connective tissue
Often presents as throbbing and well localized,
Visceral pain
Pain arising from internal organs such as the large intestine or
pancreas
Visceral pain can manifest as pain feeling as if it is coming from
other Structures (referred) Or as a more localized phenomenon.
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TypesofPain
Neuropathic and Functional Pain
Neuropathic pain, in which there is ongoing peripheral
nerve injury (e.g., postherpetic neuralgia, painful diabetic
neuropathy, or chemotherapy induced neuropathy), or in the
CNS (e.g., following an ischemic stroke or with multiple
sclerosis).
Often is described in terms of chronic pain.
Functional pain can be thought of as abnormal operation of
the nervous
Centrally mediated disturbance in pain processing with
in the CNS
E.g., Irritable bowel syndrome, sympathetic induced
pain, tension-type headaches
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Pathophysiology:nociceptive pain
Nociception occur in terms of stimulation, transmission,
perception, andmodulation
Stimulation/ Transduction
The first step leading to the sensation of pain is stimulation of
free nerve endings known asnociceptors.
These receptors are found in both somatic andvisceral
structures.
They are activated and sensitized by mechanical, thermal, and
chemical impulses
They distinguish between noxious and innocuous stimuli,
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The underlying mechanism of these noxious stimuli may be
the release of :
Bradykinins, hydrogen and potassiumions
Prostaglandins, histamine,interleukins,
Tumor necrosis factor alfa, serotonin, and substanceP
Receptor activation leads to action potentials that are
transmitted along afferent nerve fibers to the spinal cord
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Conduction
Nociceptor activation leads to the conversion of a chemical
signal into an electrical signal.
This requires voltage-gated sodium channels, which produce
the generation of action potentials that are conducted along
primary afferent A-δ and C-polymodal nerve fibers to the
dorsal horn of the spinal cord.
Stimulation of large-diameter, sparsely myelinated A-δ fibers
evokes sharp, well-localized pain, whereas stimulation of
unmyelinated, small-diameter C fibers produces aching, poorly
localized pain.
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Transmission
These afferent, nociceptive pain fibers synapse in various layers
(laminae) of the spinal cord’s dorsal horn and convert the
electrical signal back into a chemical signal by releasing
excitatory neurotransmitters, such as glutamate and substance P.
The N-type voltage-gated calcium channels regulate the release
of these excitatory neurotransmitters.
Pain signals reach the brain through a host of ascending spinal
cord pathways, which include the spinothalamic tract.
The thalamus acts as a relay station within the brain, as these
pathways ascend and pass the impulses to higher cortical
structures where pain can be processed further.
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Modulation
Signal can be attenuated/inhibited by descending pathways
that consist of endogenous opioids (eg, enkephalins and β-
endorphins), γ- aminobutyric acid (GABA), NA, or
serotonin.
Like exogenous opioids, endogenous peptides bind to
opioid receptor sites and modulate the transmission of pain
impulses.
Blockade of N-methyl-D-aspartate (NMDA) receptors may
increase the mu (μ)-receptors’ responsiveness to opiates.

Perception
• The complex interplay between ascending excitatory and
descending inhibitory pathways is thought to culminate
in a conscious experience that takes place in higher
cortical structures.
• While not well understood, we do know cognitive and
behavioral functions can modify pain.
• Thus, relaxation, distraction, meditation, and guided
mental imagery may strongly influence pain perception
and decrease pain.
• In contrast, conditions such as depression or anxiety
often worsen pain.
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8/22/2021 Compiled By: Daniel M 13

Pathophysiology:Nociceptive pain

CLASSIFICATION OF PAIN
It is helpful in guiding assessment and treatment of pain
There are numerous ways of classifying pain, such as by
type of pain (eg, nociceptive, neuropathic, inflammatory),
by pain intensity (eg, mild, moderate, or severe), or most
commonly by duration of pain (eg, acute, subacute, or
chronic pain).
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Classification
Acute Pain
Acute pain can be a useful physiologic process,warning
individuals of disease states
Severe, unremitting, undertreated acute pain,,can produce
many deleterious effects.
Untreated acute pain has also been shown to increase one's
risk for the development of chronic pain syndromes.
Acute pain is usually nociceptive in nature with common
causes, including surgery, acute illness, ,,

Classification
Chronic Pain
In some instances, pain persists for months to years,
This type of pain can be nociceptive, neuropathic/
functional, ormixed.
Chronic pain can be classified as either being associated
with cancer (cancer pain) or from noncancer etiologies
(chronic noncancer pain).

Classification

Clinicalpresentation
Acute
General
Obvious distress (e.g., trauma),
Infants may present with changes in feeding habits,
increased fussiness.
Symptoms
Can be described as sharp, dull, shock like, tingling,
shooting, radiating, fluctuating in intensity, and varying in
location .

Signs
Hypertension,tachycardia, diaphoresis, mydriasis, and
pallor, but these signsare not diagnostic.
In some cases there are noobvious signs.
Comorbid conditions usually not present.

Chronic
General
Can appear to have no noticeablesuffering.
Attention also must be given tomental/emotional
factors that alter the painthreshold.
Symptoms
Can be described as sharp, dull, shock-like, tingling,
shooting, radiating, fluctuating in intensity, and varying
in location
Over time, the pain stimulus may cause symptoms that
completely change (e.g., sharp to dull, obvious to vague

Signs
Hypertension, tachycardia, diaphoresis, mydriasis, and
pallor are seldom present.
In most cases there are noobvious signs.
Comorbid conditions often present

Treatment
PharmacologicTreatment
Many consider pharmacologic treatment to be the
cornerstone of painmanagement.
Nonopioid Agents
Asprin ,Acetaminophen, NSAIDs often are preferred
over opiates in the treatment of mild-to-moderate pain
NSAIDs may be particularly useful in the management
of cancer-related bone pain
Opioid Agents… are preferred over opiates in the treatment
of moderate- severe type of pain

Non-pharmacological treatment
 Pain is influenced by psychological, cultural, social,
and spiritual factors which should also be addressed
 Non-pharmacological treatments do not replace
pharmacological treatment, but they may be
complementary
TOTAL PAIN
PHYSICAL
PSYCHOLOGICAL EMOTIONAL
SPIRITUAL

8/22/2021 CompiledBy:DanielM
 May reduce the perception of pain, assist in relaxation,
or improve sleep
 Dance therapy: Uses movement to improve mental
and physical well-being
 Music therapy: Listening to or making music may
lower stress and improve mood
 Acupuncture: Insertion and manipulation of
needles, pressure, or low-frequency electric current
at specific points
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 Physical therapy: Movement helps to build strength,
maintain energy, and contributes to overall well-being
 Positioning therapy: Moving bedridden patients and
changing their position prevents bed sores and injury
 Massage therapy: Rubbing and manipulating muscles,
which increases circulation and relaxation
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 Social support: Supportive counseling and referrals to
community resources and services
 Spiritual and religious support: Depending on their
beliefs and faith, some patients may find support
through prayer and meditation
 Herbs: May be helpful or harmful
 Hot and cold therapy: Either one may help to decrease
pain
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 Relaxation: Most commonly used non-pharmacological
technique-teach patients to intentionally relax to reduce
tension and stress
 Deep and slow breathing: Influences autonomic and
pain processing in combination with relaxation
 Distraction: Focus the patient’s attention away from the
pain
 Aromatherapy: Use essential oils to balance, relax, and
stimulate the body, mind, and soul
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Remember
 Not all of these approaches will work for everyone
 Do not assume that all non-pharmacological
treatments are safe.
 Some have contraindications
– Just because natural remedies, such as herbs,
have been around for a long time does not mean
that they work or that they are harmless
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How to treat pain?
The World Health Organization has developed a
simple algorithm, or model for pain treatment
Extremely effective for patients with acute pain,
cancer pain, and neuropathic pain (nerve pain)
80-90% of people are effectively treated

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Mild pain
Moderate pain
Severe pain
Step 1
Non-opioid
Step 2
Weak opioid
Step 3
Strong opioid
+/- adjuvant
+/- non-opioid
+/- adjuvant
+/- non-opioid
+/- adjuvant
Consider prophylactic laxatives to avoid constipation
Step up if pain
persists
or increases
Step up if pain
persists
or increases
Non-opioids ibuprofen or other NSAID, paracetamol (acetaminophen), or aspirin
Weak opioids codeine, tramadol, or low-dose morphine
Strong opioids morphine, fentanyl, oxycodone, hydromorphone, buprenorphine
Adjuvants antidepressant, anticonvulsant, antispasmodic, muscle relaxant,
bisphosphonate, or corticosteroid
WHO Analgesic Ladder: adults
CompiledBy:DanielM
8/22/2021

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Mild pain
Moderate or
Severe pain
Step 1
Non-opioid
Step 2
Strong opioid
+/- adjuvant
+/- non-opioid
+/- adjuvant
Consider prophylactic laxatives to avoid
constipation
Step up if
pain persists
or increases
Non-opioids Age>3 mos: ibuprofen or paracetamol (acetaminophen); Age<3 mos:
paracetamol
Strong opioids morphine (medicine of choice) or fentanyl, oxycodone, hydromorphone,
buprenorphine
Adjuvants antidepressant, anticonvulsant, antispasmodic, muscle relaxant,
bisphosphonate, or corticosteroid
WHO Analgesic Ladder: Pediatric
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Key Recommendations of the Centers for Disease Control and
Prevention Guideline for Prescribing Opioids for Chronic Pain
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Reading assignment: Steps for Equianalgesic Opioid Calculation
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T
reatment
OpioidAgents
Opioids are often the next logical step in the management
of acute pain and cancer-relatedchronic pain.
They also may be an effective treatment optionin the
management of chronic non-cancerpain.
83

Treatment
Morphine
Despite the availability of several newer agents, morphine
remains the prototype opiateanalgesic.
As new opioid and nonopioid compounds are developed,
their efficacy and side-effect profiles are typically compared
against morphine as the standard.
Many clinicians consider morphine the first-line agent when
treating moderate-to-severe pain.
Morphine can be given parenterally, orally, or rectally
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Treatment
Side effects can be numerous, particularly when morphine
is first initiated or when doses are significantly increased.
Morphine causes nausea and vomiting throughdirect
stimulation of the chemoreceptor triggerzone.
Opioid-induced nausea subsides overtime.
Although euphoria and dysphoria have been reported,
morphine's unpleasant effects are more prominentwhen
administered topatients not experiencing pain
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Treatment
As doses of morphine are increased, the respiratory
center becomes less responsive to carbon dioxide,
causing progressive respiratory depression.
Respiratory depression often manifests as a decreasein
respiratory rate
Cough reflex is also depressed
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Treatment
However,morphine does produce venous and arteriolar vessel
dilation, and orthostatic hypotensionmay result.
Hypovolemic patients are more susceptible to
morphine-induced cardiovascularchanges
Because morphine prompts a decrease in myocardial oxygen
demand in ischemic cardiacpatients,
It is often considered the drug of choice when using
opioids to treat pain associated with MI.
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Treatment
Morphine-induced respiratory depression can be
reversed by pure opioid antagonists, such as naloxone.
Morphine used cautiously in
Underlying pulmonary disease
Therapeutic doses of morphine have minimal effectson BP
,
HR , or cardiac rhythm when patients are supine
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Treatment
Morphine also affects the hypothalamus inhibitingthe
release of gonadotropin-relasing hormone,
Morphine and other opioids also appear to be
immunosuppressive
Othe drugs of the class:
Hydromorphone, Oxymorphone ,Levorphanol
Codeine, Hydrocodone,Oxycodone

Treatment
Meperidine and Congeners (Phenylpiperidines)
Meperidine( pethidine ) has a pharmacologicprofile
comparable with that ofmorphine;
However, it is not as potent and has a shorter analgesic
duration.
Meperidine offers noanalgesic advantage over morphine,
has greater toxicity and should be limited in use.
In particular, avoid long-term usage, and use in patients at
greatest risk for toxicity( elderly, renal impairment)

Treatment
Meperidine
IM 50–150 mg every 3–4 h: Use in severepain
IV5–10 mg every 5 min prn
Oral rote not recommended
Do not use in renalfailure
May precipitate tremors, myoclonus, andseizures
Monoamine oxidase inhibitors can induce
hyperpyrexia and/or seizures or opioidoverdose
symptoms

Treatment
Fentanyl
Is a synthetic opioid structurally related to meperidine that
is used oftenin anesthesiology as an adjunct to general
anesthesia.
This agent is more potent and faster actingthan
meperidine
It can be administered parenterally, transmucosally, and
transdermally.

Treatment
Fentanyl
IV25–50 mcg/h Used in severepain
IM 50–100 mcg every 1–2h
Transdermal 25 mcg/h every 72h
Do not use transdermal in acute pain
Transmucosal for breakthrough cancer pain in patients
already receiving or tolerant to opioids.

Treatment
Methadone
Methadone has oral efficacy, extended duration of action,
and ability to suppress withdrawal symptoms in heroin
addicts.
With repeated doses, the analgesic duration of action of
methadone is prolonged,but excessive sedation may also
result.
Although effective for acute pain, it is usually used for
chronic cancer pain.

Treatment
Methadone
PO2.5–10 mg every 8–12 h
Effective in severe chronicpain
IM 2.5–10 mg every 8–12h
Some chronic pain patients can be dosed every 12 h

Codeine
Adult dose: 30-60mg by mouth every 4 hours; maximum
daily dose 240mg
If pain relief is not achieved with 240mg/day, move to
strong opioid
Can be combined with Step 1 analgesic
Give laxative to avoid constipation unless patient has
diarrhoea
Genetic variability can lead to variable rates of
metabolism which may make codeine ineffective or
lead to excessive side effects

Treatment
Tramadol
 Centrally acting analgesic for moderate to moderately
severe pain, binds to μ opiate receptors and weakly inhibits
norepinephrine and serotonin reuptake.
Tramadol has a side-effect profile similar to that of
other opioid analgesics.
It may also enhance the risk of seizures.
It may be useful for treating chronic pain, especially
neuropathic pain,

Table-2commonadverseeffectsofopioidanalgesics
4/ 18/ 2018
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Treatment
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Treatment
Adjuvant Analgesics for chronicpain
Adjuvant analgesics are pharmacologic agents with
individual characteristics that make them useful in the
management of pain but that typically are not
classified as analgesics.
Examples of adjuvant analgesics include:
Anticonvulsants (e.g., gabapentin, whichmay
decrease neuronal excitability),
Tricyclic antidepressants,
Serotonin and norepinephrine reuptakeinhibitor
Topically applied local anesthetics
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Treatment
RegionalAnalgesia
Regional analgesia with properly administered local
anesthetics can provide relief of both acute and chronic
pain
These agents can be positioned by injection or topically.
Lidocaine in the form of a patch has proven effective in
treating focal neuropathic pain.
Regional application of local anesthetics relieve pain by
blocking nerve impulses.
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Summary
Pain is one of the most common reasons for which
patients
Seek medical attention,
Yetit remains significantly undertreated despite the
availability of effective medications and other
therapies
Effective treatment considers the cause, duration, and
intensity of pain
And matches the appropriate intervention to the situation.
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Summary
In general, the reasonsfor under treatment include :
Alack of understanding of pain management
principles Orthe pharmacologic properties of the
drugs;
an overestimation of the risk of addiction
poor communication between the patient and
medical personnel
57

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