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1. What is Pain
lecture 7
Lecturer: Nadia shamasnah

2. The International Association for the Study of
Pain definition of pain
• “An unpleasant sensory and emotional experience associated with
actual or potential tissue damage.

3. Noxious stimuli and responses
• There are three categories of noxious stimuli:
• mechanical (pressure, swelling, abscess, incision, tumour growth);
• thermal (burn, scald);
• chemical (excitatory neurotransmitter, toxic substance, ischaemia,
infection).

4. • The cause of stimulation may be internal, such as pressure exerted by a tumor or
external, for example, a burn.
• This noxious stimulation causes a release of chemical mediators from the damaged
cells including:
• prostaglandin;
• bradykinin;
• serotonin;
• substance P;
• potassium;
• histamine.

5. • These chemical mediators activate and/or sensitize the nociceptors to
the noxious stimuli. In order for a pain impulse to be generated, an
exchange of sodium and potassium ions (de-polarisation and re-
polarisation) occurs at the cell membranes. This results in an action
potential and generation of a pain impulse.

6. Types of pain

7. Acute pain
• Acute pain is short-term pain that comes on suddenly and has a
specific cause, usually tissue injury. Generally, it lasts for fewer than
six months and goes away once the underlying cause is treated.
• Acute pain tends to start out sharp or intense before gradually
improving.

8. Common causes of acute pain include:
• broken bones
• surgery
• dental work
• labor and childbirth
• cuts
• burns

9. Chronic pain
• Pain that lasts for more than six months, even after the original injury has
healed, is considered chronic.
• Chronic pain can last for years and range from mild to severe on any given day.
• While past injuries or damage can cause chronic pain, sometimes there’s no
apparent cause.
• Without proper management, chronic pain can start to impact the quality of
life. As a result, people living with chronic pain may develop symptoms of
anxiety or depression.

10. • Other symptoms that can accompany chronic pain include:
• tense muscles
• lack of energy
• limited mobility

11. • Some common examples of chronic pain include:
• frequent headaches
• nerve damage pain
• low back pain
• arthritis pain

12. Nociceptive pain
• Nociceptive pain is the most common type of pain. It’s caused by
stimulation of nociceptors, which are pain receptors for tissue injury.
• You have nociceptors throughout the body, especially in skin and internal
organs. When they’re stimulated by potential harm, such as a cut or other
injury, they send electrical signals to the brain, causing the feeling of pain.
• This type of pain you usually feel when you have any type of injury or
inflammation. Nociceptive pain can be either acute or chronic. It can also
be further classified as being either visceral or somatic.

13. Visceral pain
• Visceral pain results from injuries or damage to the internal organs. You can
feel it in the trunk area of the body, which includes chest, abdomen, and
pelvis. It’s often hard to pinpoint the exact location of visceral pain.
• Visceral pain is often described as:
• pressure
• aching
• squeezing
• cramping

14. • You may also notice other symptoms such as nausea or vomiting, as
well as changes in body temperature, heart rate, or blood pressure.
• Examples of things that cause visceral pain include:
• gallstones
• appendicitis
• irritable bowel syndrome

15. Somatic pain
• Somatic pain results from stimulation of the pain receptors in tissues, rather than
internal organs.
• This includes skin, muscles, joints, connective tissues, and bones.
• It’s often easier to pinpoint the location of somatic pain rather than visceral pain.
• Somatic pain usually feels like a constant aching .
• It can be further classified as either deep or superficial:
• For example, a tear in a tendon will cause deep somatic pain, while a canker sore on
your inner check causes superficial somatic pain.

16. Examples of somatic pain include:
• bone fractures
• strained muscles
• connective tissue diseases, such as osteoporosis
• cancer that affects the skin or bones
• skin cuts, scrapes, and burns
• joint pain, including arthritis pain

17. Neuropathic pain
• Neuropathic pain results from damage to or dysfunction of the nervous system. This
results in damaged or dysfunctional nerves misfiring pain signals. This pain seems to
come out of nowhere, rather than in response to any specific injury.
• Neuropathic pain is described as:
• burning
• freezing
• numbness
• tingling
• shooting
• stabbing
• electric shocks

18. • Diabetes is a common cause of neuropathic pain. Other sources of nerve injury or dysfunction
that can lead to neuropathic pain include:
• chronic alcohol consumption
• accidents
• infections
• facial nerve problems
• spinal nerve inflammation or compression
• carpal tunnel syndrome
• HIV
• central nervous system disorders, such as multiple sclerosis or Parkinson’s disease
• radiation
• chemotherapy drugs

19. • Pain is a very personal experience that varies from person to person.
What feels very painful to one person may only feel like mild pain to
another. And other factors, such as the emotional state and overall
physical health, can play a big role in how we feel pain.

20. Pain related questions
• how long you’ve had the pain
• how often your pain occurs
• what brought on your pain
• what activities or movements make your pain better or worse
• where you feel the pain
• whether your pain is localized to one spot or spread out
• if your pain comes and goes or is constant

23. WHO Analgesic Ladder
• The WHO analgesic ladder was a strategy proposed by the World
Health Organization (WHO), in 1986, to provide adequate pain relief
for cancer patients.
• The analgesic ladder was part of a vast health program termed the
WHO Cancer Pain and Palliative Care Program aimed at improving
strategies for cancer pain management through educational
campaigns, the creation of shared strategies, and the development of
a global network of support.

24. • This analgesic path, developed following the recommendations of an
international group of experts, has undergone several modifications
over the years and is currently applied for managing cancer pain but
also acute and chronic non-cancer painful conditions due to a broader
spectrum of diseases such as degenerative disorders, musculoskeletal
diseases, neuropathic pain disorders, and other types of chronic pain.

25. The original ladder mainly consisted of three steps:
• First step. Mild pain: non-opioid analgesics such as nonsteroidal anti-
inflammatory drugs (NSAIDs) or acetaminophen with or without adjuvants
• Second step. Moderate pain: weak opioids (hydrocodone, codeine,
tramadol) with or without non-opioid analgesics, and with or without
adjuvants
• Third step. Severe and persistent pain: potent opioids (morphine,
methadone, fentanyl, oxycodone, buprenorphine, tapentadol,
hydromorphone, oxymorphone) with or without non-opioid analgesics, and
with or without adjuvants

26. • The term adjuvant refers to a vast set of drugs belonging to different
classes. Although their administration is typically for indications other
than pain treatment, these medications can be of particular help in
various painful conditions.

27. • Adjuvants, also called co-analgesics, include:
• antidepressants including tricyclic antidepressants (TCAs) such as
amitriptyline and nortriptyline, serotonin-norepinephrine reuptake
inhibitors (SNRIs) such as duloxetine and venlafaxine,

28. • anticonvulsants like gabapentin and pregabalin,
• topical anesthetics (e.g., lidocaine patch), topical therapies (e.g.,
capsaicin), corticosteroids, bisphosphonates, and cannabinoids
• Interestingly, although adjuvants are coadministered with analgesics,
they are indicated as a first-line treatment option for the treatment of
specific pain conditions. For instance, the European Federation of
Neurological Societies (ENS) recommended the use of duloxetine, or
anticonvulsants, or a TCA for diabetic painful neuropathy treatment.

29. • The key concept of the ladder is that it is essential to have adequate
knowledge about pain, to assess its degree in a patient through
proper evaluation, and to prescribe appropriate medications.
• As many patients will receive opioids eventually, it is essential to
balance the optimum dosage with the side effects of the drug.
• Moreover, opioid rotation can be adopted to improve analgesia and
reduce side effects.

30. • patients should receive education about the uses and side effects of
drugs to avoid misuse or abuse without compromising their beneficial
aspects.

31. • The original WHO ladder was unidirectional, starting from the lowest step of
NSAIDs, including COX-inhibitors, or acetaminophen, and heading up towards the
strong opioids, depending on the patient’s pain.
• Scholars in the field suggested eliminating the second level as weak opioids
contribute very little towards pain control.
• In case of moderate pain, it might be more useful to prescribe third step opioids
although administered at reduced dosages (e.g., morphine 30 mg per day, orally).
• According to some authors, moreover, it should be necessary to distinguish
pathways for the treatment of acute pain, from more specific treatments for use in
long-lasting cancer pain.[4] However, the real limitation of the original scale was
the impossibility of integrating non-pharmacological treatments into the therapy
path. As a consequence, a fourth step was added to the ladder

33. • It includes numerous non-pharmacological procedures that are strong
recommendations for treating persistent pain, even in combination with the
use of strong opioids or other medications.
• This group of encompasses interventional and minimally invasive procedures
such as epidural analgesia, intrathecal administration of analgesic and local
anesthetic drugs with or without pumps, neurosurgical procedures (e.g.,
lumbar percutaneous adhesiolysis, cordotomy), neuromodulation strategies
(e.g., brain stimulators, spinal cord stimulation), nerve blocks, ablative
procedures (e.g., alcoholization, radiofrequency, microwave, cryoablation
ablations; laser-induced thermotherapy, irreversible electroporation,
electrochemotherapy), cementoplasty as well as palliation radiotherapy.

34. • This updated WHO latter focused on the quality of life, was intended
as a bidirectional approach, extending the strategy to treat acute pain
as well.
• For acute pain, the strongest analgesic (for that intensity of pain) is
the initial therapy and later toned down, whereas, for chronic pain,
employing a step-wise approach from bottom-to-top.
• However, clinicians should also provide de-escalation in the case of
chronic pain resolution.

35. Issues of Concern
• The design of the analgesic ladder was so that it could be easily used
even by non-pain medicine experts. However, the continued referral
of patients to pain specialists proves otherwise.
• The lack of proper knowledge of drugs, under dosing and wrong
timing of drugs, fear of addiction in patients, and lack of public
awareness are severe limitations that can come in the way of proper
implementation of the strategy.

36. • Another limitation concerns the placement of drugs.
• Placing NSAIDs at the bottom rung of the ladder could lead to a false
belief that this represents the most secure treatment.
• In daily clinical practice, it often happens that patients take these
drugs even for long periods. Also, long-term use of NSAIDs combined
with opioids for the treatment of moderate pain (second step) can
lead to much more serious side effects than those described for
opioids.

37. • A significant issue of concern regards the management of pure neuropathic pain.
• This type of pain has complex pathophysiology and mechanisms that involve
different regions of the central nervous system, or specific structures of the
peripheral nervous system.
• An injury in these regions can trigger a cascade of events culminating in the
phenomena of peripheral and central sensitization.
• In this context, opioids have little or no efficacy, and other strategies are necessary.
• other clinical conditions are poorly manageable following ladder rules. For
example, in fibromyalgia, the drugs of the first two steps are often of poor efficacy,
whereas the use of opioids can induce dangerous, addictive phenomena as well as
being a treatment with little scientific evidence of efficacy.

38. • Experts in pain medicine found this approach one-dimensional as it concentrated
only on the physical aspect of pain. For this reason, other methods have been
proposed.
• For instance, the International Association For The Study Of Pain (IASP) suggested
adopting a therapeutic approach more focused on the type of pain (i.e., mechanism)
and on the mechanism of action of the drugs used to treat it.
• Therefore, in the case of chronic nociceptive pain on an inflammatory basis, it would
be more appropriate to use steroids or NSAIDs. On the other hand, low-inflammatory
nociceptive pain should receive treatment with opioids and non-opioid analgesics.
• Finally, neuropathic pain may require antidepressants or anticonvulsants, and specific
drugs in certain rheumatologic clinical conditions (e.g., colchicine to treat gout).

39. • There have been other proposed suggestions in attempts to offer a more precise
methodology. Leung, for instance, suggested a new analgesic model represented
as a platform where pain management follows a three-dimensional perspective
that can combine with the classical analgesics, based on the pain condition.
• More recently, Cuomo et al. proposed the so-called "multimodal trolley
approach," which gives importance to the physical, psychological, and emotional
causes of pain.
• The model underlies the need for personalized therapy and suggests that pain is
not merely a sensory discomfort experienced by the patient but also
incorporates the patient's perceptual, homeostatic, and behavioral response to
an injury or chronic illness.

40. • Through this approach, clinicians can dynamically manage pain by
combining several pharmacologic and non-pharmacologic strategies
according to the physiopathology of pain, pain features, and the
complexity of symptoms, the presence of comorbidity, and the physio
pathological factors and the social context.
• Consequently, a wide range of non-pharmacological approaches such
as yoga, acupuncture, psychotherapy, occupational therapy, are
present in specific 'drawers' of the trolley and can be used according
to the clinical needs and skills of the operator, as well as available
resources.

41. Clinical Significance
• Even with the drawbacks, the strategy includes a simple and effective guideline on
the administration of analgesics that is valid even today. The main components
include:
• Oral dosing of drugs whenever possible (as opposed to intravenous, rectal, etc.)
• Around-the-clock administration rather than on-demand.
• The prescription must follow the pharmacokinetic characteristics of the drugs.
• Analgesics must be prescribed according to pain intensity as evaluated by a scale
of pain severity. For this purpose, a clinical examination must combine with an
adequate assessment of the pain.

42. • Individualized therapy (including dosing) addresses the concerns of
the patient. This method presupposes is that there is no standardized
dosage in the treatment of pain.
• Probably, it is the biggest challenge in pain medicine, as the
medication must be continuously adapted to the patient, balancing
analgesic desired effects and the possible occurrence of side effects.

43. • Proper adherence to pain medications as any alteration in the dosing
can lead to a recurrence of pain.
• Pain accounts for one of the top five reasons for consultation. A better
understanding of the physiology and the psychological aspects is
necessary to come up with an ideal approach towards pain control.
The WHO analgesic ladder can remain a foundational treatment for
chronic pain, upon which clinicians can add new modalities.

44. • Nursing, Allied Health, and Inter professional Team Interventions
• The patients should be treated with the utmost respect and empathy to make
them as comfortable as possible.
• Opioids administration should only be when their benefits outweigh their risks as
it carries a considerable risk of dependence.
• Nurses should make sure they understand the physicians' directions regarding the
drug, its dosage, and side effects to provide the optimum amount of medication.
• Any doubts regarding the drug should have clarification from the ordering
physician. The pharmacists should keep accurate track of all the prescriptions,
and report any suspicion of drug misuse.

45. • Nursing, Allied Health, and Interp rofessional Team Monitoring
• Pain management in chronic diseases may be time-consuming and boring for
the patient. It is essential to have regular follow-up visits to assess the
progression of the disease and the efficacy of therapy and to make any
necessary modifications. The patients should be encouraged to stay
motivated and appreciated for any improvement or progress.
• Hospitalized patients on opioids should be monitored regularly for their
vitals, especially respiratory rate, to check for any adverse effects. Bed-
ridden patients should receive proper care to maintain hygiene and avoid
complications like bedsores and deep vein thrombosis.