Pathophys and Assessment of Pain

Question 1

Pain is one of main reasons:

Answer 1

is one of main reasons patients seek care

Question 2

purpose of rating person’s pain?

Answer 2

assess their level of pain and to determine if interventions are effectively helping that pain or not
-pain has protective function

Question 3

Somatogenic pain:
nociceptive pain:
neuropathic pain:

Answer 3

pain with usually known cause localized in body tissue

• tissue damage(skin, muscle, bones, joints) and visceral organs
• caused by nerve damage

Question 4

psychogenic pain

Answer 4

pain for which there is no know physical cause but processing of sensitive information in CNS is disturbed
-psych evaluation will evidence that the pain itself is predominantly sustained by psych factors

Question 5

Acute pain

Answer 5

a protective mechanism that alerts the individual to a condition or experience that is immediately harmful to the body

Onset……usually sudden

Question 6

Pain effects on the Respiratory system

Answer 6

Reduction in lung volume (Tidal volume, functional residual capacity, vital capacity)
Regional lung collapse (atelectasis)
Decrease alveolar ventilation leads to hypoxemia and hypercapnia
Cough is decreased
Secretions are retained
Chances of chest infections are increased
Increased O2 consumption

Question 7

Stimulation of what nervous system occur during acute pain:

Answer 7

Autonomic nervous system; mydriasis(dilated pupils, tachcardia, tachypnea, sweating, vasoconstriction

Question 8

Inadequate relief of acute pain can contribute to:

Answer 8

hypercoagulability and impaired immunity, leading to such complications as venous thromboembolic disease and infections-like PE
Inadequately controlled acute pain can be a factor in the development of chronic pain, extended hospital stay, readmission, and patient dissatisfaction

Question 9

Nociceptive pain:

Answer 9

involves the normal neural processing of pain that occurs when free nerve endings are activated by tissue damage or inflammation

Question 10

Nociceptive involves the 4 processes of :

Answer 10

Transduction
Transmission
Modulation
Perception

Question 11

Neuropathic pain:

Answer 11

involves the abnormal processing of stimuli from the peripheral or central nervous systems and is thought to serve no useful purpose

Question 12

Pain stimuli are sense by:

Answer 12

specialized nociceptors that are the nerve terminals of the primary afferent fibers
The pain signal is then transmitted to the dorsal horn of the spinal column and transmitted through the central nervous system (CNS) where it is processed and interpreted in the somatosensory cerebral cortex

Question 13

The majority of signals are sent contralaterally through:

Answer 13

The spinothalamic tract which synapses in the thalamus

Question 14

Transduction:
Transmission:
Modulation:
Perception:

Answer 14

• Transduction refers to the conversion of a noxious stimulus (thermal, mechanical, or chemical) into electrical activity in the peripheral terminals of nociceptor sensory fibers
• Transmission refers to the passage of action potentials from the peripheral terminal along axons to the central terminal of nociceptors in the central nervous system. Conduction is the synaptic transfer of input from one neuron to another
• Modulation refers to the alteration (eg, augmentation or suppression) of sensory input
• Perception refers to the “decoding”/interpretation of afferent input in the brain that gives rise to the individual’s specific sensory experience

Question 15

Nociceptors:

Answer 15

Highly specialized subset of primary sensory neurons that respond only to pain stimuli

Categorized by the kind of stimulation they respond to and the nature of their response
Most noxious stimuli activate a variety of nociceptor types in the affected area. Their signals sum to produce the nociceptive input, leading to the subjective sense of pain

Question 16

Myelinated nociceptors:

What kind of fibers and what are they responsible for ?

Answer 16

Relatively fast conducting A-delta fibers

Responsible for the first immediate sharp pain

Question 17

Unmyelinated C fibers:

Answer 17

constitute the majority of peripheral nociceptors
These are slow conducting primary afferents that recover from fatigue more slowly than those of A-delta nociceptors
C fibers mediate delayed and longer-lasting pain, typically characterized as dull

Question 18

Physiological responses to acute pain may include:

Answer 18

• increased heart rate - diaphoresis
• increased respiratory rate - ↑ blood sugar
• elevated blood pressure - ↓ gastric acid secretion
• pallor or flushing, - ↓ gastric motility
• dilated pupils - ↓ blood flow to the viscera, kidneys, skin
  - nausea occasionally

Question 19

Relief from occurs when:

Answer 19

after the chemical mediators that stimulate the nociceptors are removed

Question 20

Perception of pain involves:

Answer 20

Perception, the conscious experience of pain, involves both the sensory and affective components of pain

Question 21

Final Nociceptive process-modulation results from:

Answer 21

activation of the midbrain

Question 22

Adaptive pain:

Answer 22

contributes to survival by protecting the organism from injury and/or promoting healing when injury has occurred

Question 23

Maladaptive or chronic pain is:

Answer 23

is pain as disease and represents pathologic functioning of the nervous system

Question 24

Chronic pain is defined as:

Answer 24

is persistent or intermittent and usually defined as lasting at least 6 months
has been defined as pain which lasts beyond the ordinary duration of time that an insult or injury to the body needs to heal
An argument has been made that the term “persistent pain” should be used in lieu of “chronic pain”
The cause is often unknown
Often develops insidiously
Very often is associated with a sense of hopelessness and helplessness

Question 25

What is the most common type of chronic pain?

Answer 25

Persistent lower back pain

Result of poor muscle tone, inactivity, muscle pain, sudden, vigorous exercise

Question 26

What are the major causes of pain hypersensitivity after injury?

Answer 26

Peripheral and central sensitization

Question 27

Chronic pain can produce significant behavioral and psych changes:

Answer 27

• depression
• an attempt to keep pain-related behaviour to a minimum
• sleeping disorders
• preoccupation with the pain
• tendency to deny pain

Question 28

Interminttent pain:

Persistent:

Answer 28

Intermittent pain produces a physiologic response similar to acute pain
Persistent pain allows for adaptation (functions of the body are normal but the pain is not relieved)

Question 29

The pain threshold is the point at which:

Answer 29

point at which a stimulus is perceived
as pain…..Does not vary significantly among healthy people or in the same
person over time

Perceptual dominance- intense pain at one location of the body that may cause an increase in the pain threshold in another location

Question 30

Pain tolerance is expressed as:

Answer 30

The pain tolerance is expressed as duration of time or the
intensity of pain that an individual will endure before initiation of overt pain responses
It is influenced by:
- person’s cultural prescriptions
- expectations
- role behaviours
- physical and mental health

Question 31

Pain tolerance is generally decreased:

Answer 31

• with repeated exposure to pain
  
  • by fatigue, anger, boredom, apprehension
    
    • sleep deprivation

Question 32

Tolerance to pain may be increased by:

Answer 32

• by alcohol consumption
  - medication, hypnosis
  - warmth, distracting activities
  - strong beliefs or faith

Question 33

Pain threshold tends to increase with aging due to:

Answer 33

This change is probably caused by peripheral neuropathies and changes in the thickness of the skin

Question 34

The portions of the nervous system responsible for sensation and perception of pain:

Answer 34

CNS
Afferent pathways
Efferent pathways

Question 35

Portion of CNS involved in interpretation of pain signals:

Answer 35

• limbic system
• reticular formation
• thalamus
• hypothalamus
• cortex

Question 36

The afferent portion is composed of:

Afferent pathways terminate:

Answer 36

The afferent portion is composed of:
a) nociceptors (nerve endings of nociceptive nerve cells)
b) afferent nerve fibers
c) spinal cord network
Afferent pathways: terminate in the dorsal horn of the spinal cord (1st afferent neuron)

Question 37

The efferent pathways composed of:

Answer 37

composed of the fibers connecting the:
reticular formation
midbrain
substantia gelatinosa
-involved in different behavioral and psychological responses to pain
-also responsible for modulating pain sensation

Question 38

The ______ is the site of perceiving, describing, and localizing pain

Answer 38

Thalamus

Question 39

Parts of thalamus, brain stem, and reticular formation:

Answer 39

Identify dull longer-lasting, and diffuse pain

Question 40

The reticular formation and lymbic system:

Answer 40

Control the emotional and affective response to pain

-Because the cortex, thalamus and brainstem are interconnected with the hypothalamus and autonomic nervous system….. perception of pain is associated with an autonomic response

Question 41

Nociceptive pain
Nociceptors:
Stimulators:

Answer 41

Nociceptors: Endings of small unmyelinated and lightly myelinated afferent neurons
Stimulators: Chemical, mechanical and thermal noxae
-Mild stimulation → positive, pleasurable sensation
(e.g. tickling)
-Strong stimulation → pain

 Location:
    muscles
    tendons
    epidermis
    subcutaneous tissue
    joints
    visceral organs
    - not evenly distributed in the body (in skin more then in internal structures)

Question 42

Which neurons are responsible for the transmission of dull or diffuse burning or aching sensations?

Answer 42

The small unmyelinated C-neurons

Question 43

Which neurons carry well localized, sharp pain sensations?

Answer 43

Large myelinated, A-delta fibers

Question 44

Role of the efferent analgesic system?

Answer 44

Inhibition of afferent pain signals
- pain afferents on their way up to the CNS send branches to periaqueductal gray (PAG) matter surrounding the cerebral aqueduct in the midbrain, and stimulates the neurons there which → activation of efferent (descendent) anti-nociceptive pathways

Question 45

The neospinothalamic tract carries info to:

Answer 45

• mid-brain
• thalamus
• post central gyrus (where pain is perceived)

Question 46

The paleospinothalamic tract carries info to :

Answer 46

• reticular formation
• pons
• limbic system
• mid brain

Question 47

Gate control theory

Answer 47

• Most rational explanation of pain production and modulation is based on the Gate Control Theory
  
  • A closed gate leads to decreases stimulation of T-cells which decreases transmission of impulses, and diminishes pain perception

Stimulation of small fibers input inhibits cells in SG and “opens the gate“

• An open gate increases the stimulation of transmission cells (T-cells) → ↑ transmission of impulses → enhances pain perception

Question 48

Action of endorphins

Answer 48

All endorphins act by attaching opiate receptors to the plasma membrane of the afferent neuron
The result then is inhibition of the releasing neurotransmitter, thus….
blocking the transmission of the painful stimulus

Question 49

Neuropathic pain:

Answer 49

-Arises from abnormal neural activity secondary to disease, injury, or dysfunction of the nervous system
-It commonly persists without ongoing disease (eg, diabetic neuropathy, trigeminal neuralgia, or thalamic pain syndrome)
Further divided into: sympathetically medicated pain, peripheral neuropathic pain, central pain

Question 50

What causes neuropathic pain?

Answer 50

Neuropathic pain often seems to have no obvious cause, but, some common causes of neuropathic pain include:
- Hereditary disorders - Traumatic nerve damage
Metabolic disorders, - Toxic nerve damage
Nerve ischemia, - Infection of nerve tissue
Nerve compression - Immune mediated nerve tissue damage

Question 51

Neuropathic pain

Predominating peripheral generator:

Answer 51

e.g. compression or entrapment….neuropathies, plexopathies, radiculopathies, polyneuropathies

Question 52

Predominating central generator:

Answer 52

Spinal cord injury, post-stroke pain

Question 53

Deafferentation pain

Answer 53

a term implying that sensory deficit in the painful area is a prominent feature (anaesthesia dolorosa)

Question 54

Neurophysiologic and neuroanatomic changes that may occur in peripherally generated neuropathic pain

Answer 54

• Abnormal nerve morphology
• Development of atypical connections between nerve sprouts or demyelination axons in the region of nerve damage
• anterograde and retrograde transport of compounds

Question 55

Most peripheral neuralgias are the result of :

Answer 55

Trauma and surgery
-Such a conditions do not necessarily occur as a result of damaging a major nerve trunk
but may be caused by an incision involving only small nerve branches (incisional pain)

Mechanism? the pain is thought to be due to neuroma formation in the scar tissue

Question 56

Deafferentaation pain following spinal cord injury:

Severe pain due to spinal cord and cauda equine lesions is due to:

Answer 56

Incidence of severe pain due to spinal cord and cauda equina lesions ranges from 35 to 92% of patients

This pain is ascribed to 3 causes:

 1. mechanically induced pain (fracture bones, myofascial pain)
 2. radicular pain (compression of nerve root)
    3. central pain (deafferentation mechanism)

Question 57

Psychogenic pain

Answer 57

Dysfunction of central mechanisms responsible for
processing of sensoric afferent informations…….

• releasing of mediators decreasing pain threshold
• prolonged muscle contraction due to psychogenic stress
• incresed activity of SNS → decreasing pain threhold
• inhibition of activity of descending antinociceptive system

Question 58

Neuralgias result from:

Answer 58

Damage of peripheral nerves

Includes: causalgias, sympathetically mediated pain, post-hermetic neuralgia, trigeminal neuralgia

Question 59

Causalgias:

Answer 59

Severe burning pain appearing 1-2 weeks after the nerve injury
Associated with discoloration and changes in the texture of the skin in the affected area

Question 60

Sympathetically mediated pain aka RSD

Answer 60

Occurs after peripheral nerve injury and is characterized by continuous, severe burning type pain
Vasomotor changes are present:
vasodilation
vasoconstriction
cool, cyanotic and edematous extremities