Concept of pain

1. Concept of Pain
Muhammad Zubair Shah
MSN Scholar
INS-SUIT

2. Introduction
• Pain is the fifth Vital sign and is regarded as
a symptom of an underlying condition
• Pain is a complex experience consisting of
physiological and a psychological response to a
noxious stimulus.
• Pain is a warning mechanism that protects an
organism by influencing it to withdraw from
harmful stimuli; it is primarily associated
with injury or the threat of injury.
• Pain is subjective and difficult to quantify, because
it has both an affective and a sensory component

3. Objectives
At the end of this unit, learners will be able to:
• Define the process of pain (physiological changes)
• Describe the different theories of pain theory.
• Differentiate between acute and chronic pain
• Discuss the non-pharmacologic interventions pain
management.
• Identify pharmacologic interventions for pain
management

4. Definition of Pain
The International Association for the Study of Pain
(IASP) defines pain as "an unpleasant sensory and
emotional experience that is associated with
actual or potential tissue damage, or described in
terms of such damage.

5. Pain Process
• A nociceptor is a receptor of a sensory neuron
(nerve cell) that responds to potentially damaging
stimuli by sending signals to the spinal cord and
brain. This process, called nociception, usually
causes the perception of pain
• Distributed throughout the body (skin, viscera,
muscles, joints, meninges) they can be stimulated
by mechanical, thermal or chemical stimuli.

7. Pain Process
• There are four major processes: transduction,
transmission, modulation, and perception

8. Transduction
• Transduction refers to the process by which a
painful physical or chemical stimulus is transformed
into a signal that can be carried (via transmission)
to the central nervous system and perceived as
pain.

9. Transmission
Once transduction is complete transmission of pain
begins, Painful stimuli produce nerve impulses that
travel along efferent nerve fibers.
• A-delta fiber (fast myelinated)
Send sharp localized and distinct sensation
• C-fiber (Slow unmyelinated)
Slow impulses e.g needle stick,

10. Perception
• Perception of pain occurs when the pain impulse
has been transmitted to the cortex and the person
develops conscious awareness of the intensity,
location, and quality of pain

11. Modulation
• Modulation of pain refers to activation of neural
pathways that inhibit transmission of pain
• The periaqueductal gray (PAG), dorsolateral pontine
tegmentum (DLPT), and rostroventral medulla
(RVM) are the key regions of the brain involved in
this descending pain modulation

13. Theories of Pain
• Several theoretical frameworks have been
proposed to explain the physiological basis of pain,
although none yet completely accounts for all
aspects of pain perception.
• A number of theories have been postulated to
describe mechanisms underlying pain perception.
Some of which are:

14. Theories of Pain
• Intensive Theory (Erb, 1874)
• Strong's Theory (Strong, 1895)
• Specificity Theory (Von Frey, 1895)
• Pattern Theory(Goldschneider (1920)
• Central Summation Theory (Livingstone, 1943)
• Sensory Interaction Theory (Noordenbos, 1959)
• Gate Control Theory (Melzack and Wall, 1965)

15. Gate Control Theory
• Ronald Melzack and Patrick Wall proposed the Gate Control
Theory in 1965.
• The gate control theory of pain asserts that non-painful input
closes the "gates" to painful input, which prevents pain
sensation from traveling to the central nervous system.
• Therefore, stimulation by non-noxious input is able to suppress
pain.

16. Types of Pain
• There are several ways to categorize pain. One is to
separate it into acute and chronic pain.
• Acute pain typically comes on suddenly and has a
limited duration. It's frequently caused by damage
to tissue such as bone, muscle, or organs, and the
onset is often accompanied by anxiety or emotional
distress.
• Chronic pain lasts longer than acute pain and is
generally somewhat resistant to medical treatment.
It's usually associated with a long-term illness, such
as osteoarthritis

18. Types of Pain
• Pain is often classified by the kind of damage that
causes it.
• The two main categories are pain caused by tissue
damage, also called nociceptive pain, and pain
caused by nerve damage, also called neuropathic
pain.
• A third category is psychogenic pain, which is pain
that is affected by psychological factors

19. Types of Pain
• Somatic pain, visceral pain and Cutaneous is
another classification of pain based on origin
• Somatic pain comes from the skin. muscles, and
soft tissues,
• while visceral pain comes from the internal organs.
• Cutaneous pain: is caused by stimulation of the
cutaneous nerve endings in the skin.

20. Non-pharmacological
interventions
• Non-pharmacological pain therapy refers to
interventions that do not involve the use of
medications to treat pain.
• The goals of non-pharmacological interventions are
to decrease fear, distress and anxiety, and to reduce
pain and provide patients with a sense of control.
• The advantage of non-pharmacological treatments
is that they are relatively inexpensive and safe

21. Non-pharmacological
interventions
Non-pharmacological therapies are typically
categorized into:
• Physical (sensory) interventions
• Psychological interventions

22. Physical (sensory) interventions
• Physical (sensory) interventions typically are
patient-specific and inhibit nociceptive input and
pain perception.
• Some measures that can reduce pain intensity and
improve the patient quality of life such as massage,
positioning, hot and cold treatment,
transcutaneous electrical nerve stimulation (TENS),
acupuncture and progressive muscle relaxation

23. Psychological interventions
• Continuous pain may lead to development of
maladaptive status and behavior that worsen day to
day function, increase distress, or enhancing the
experience of pain
• Most commonly used psychological interventions
are: cognitive behavioral therapy, mindfulness-
based stress reduction, acceptance and
commitment therapy (ACT), meditation, guided
imagery and biofeedback.
• Others: Spirituality and religion in pain
management and music therapy.

24. Pharmacological interventions
• Pharmacological pain therapy refers to
interventions that involve the use of medications to
treat pain.
• A wide range of drugs are used to
manage pain resulting from inflammation in
response to tissue damage, chemical
agents/pathogens (nociceptive pain) or nerve
damage (neuropathic pain).

25. Pharmacological interventions
WHO Analgesic Ladder Step 1-3
• Originally developed by the World Health
Organization (WHO) to improve management
of cancer pain
• The 3 step WHO analgesic ladder is also used for
providing stepwise pain relief for pain due to other
causes.

26. Pharmacological interventions
Non-opioid medications: Step 1 - WHO Analgesic
ladder Mild to Moderate pain:
• Non-steroidal anti-inflammatory drugs (NSAIDs)
• Paracetamol also known as acetaminophen
• Aspirin also known as acetylsalicylic acid (ASA)

27. Pharmacological interventions
Compound analgesics: Step 2 on the WHO analgesic
ladder – mild to moderate pain
• Compound analgesics are a combination of drugs in
a single tablet usually including codeine (a weak
opiate) and aspirin or paracetamol.
• Examples include co-codamol and co-dydramol
which contain codeine and paracetamol in various
formulas (8/500, 10/500, 15/500, 30/500) where
the first number refers to the amount of codeine
and the second to paracetamol

28. Pharmacological interventions
Opioid medications: Step 3 on the WHO analgesic
ladder – severe pain
• Medications derived from morphine (or synthetic
analogs) mimic the body’s own analgesic system
and are strongest and most effective painkillers
currently available.
• Opioid medications include morphine, oxycodone,
codeine, tramadol, buprenorphine, fentanyl and
diamorphine (heroin)

29. Pharmacological interventions
• Adjuvants: The WHO analgesic ladderrecommends
that patients are prescribed additional medication
to manage the symptoms of neuropathic
pain. These drugs include tricyclic antidepressants
and antiepileptic drugs
• Topical analgesics: Topical analgesics can provide
localized pain relief and are used to treat acute and
chronic pain, such as musculoskeletal and
neuropathic pain, as well as muscle pain related to
trauma.
• Topical analgesics include rubefacients, topical
NSAIDs and local anaesthetics.

30. THANK YOU