Pain Pathophysiology

Question 1

Name the type of pain. Normal response to noxious stimulus, producing protective behavioral responses to potential or actual tissue damage

Answer 1

Physiologic pain

Question 2

Name the type of pain. Sudden onset of pain, may be severe but disappears when stimulus is removed

Answer 2

Acute pain

Question 3

Name the type of pain. Pain lasting several weeks to months and persists beyond the expected healing time.

Answer 3

Chronic pain

Question 4

Name the type of pain. Originates from damage to bone, joint, muscle or skin.

Answer 4

Somatic pain

Question 5

Name the type of pain. Originates form internal organs

Answer 5

Visceral pain

Question 6

Name the type of pain. Originates from injury to the peripheral or central nervous system.

Answer 6

Neuropathic pain

Question 7

Name the type of pain. Originates from tissue damage.

Answer 7

Inflammatory pain

Question 8

Name the type of pain. Originates form one part of the body but perceived as occurring in another

Answer 8

Referred pain

Question 9

What four things make up the pain pathway

Answer 9

Transduction
Transmission
Modulation
Perception

Question 10

Describe the pain pathway.

Answer 10

Peripheral pain receptors activated by stimulus –> signal communicate through nerve fibers to the spinal cord –> nociceptive input modified at spinal cord –> conscious recognition of pain at cerebral cortex

Question 11

What do mechanoreceptors respond to?

Answer 11

Stretching, compression and crushing

Question 12

What do thermoreceptors respond to?

Answer 12

Heat/cold

Question 13

What do chemoreceptors respond to?

Answer 13

Neurotransmitters, prostaglandins and autocoids (inflammatory proteins)

Question 14

Which nerve fibers are myelinated and have fast transmission. Typically involved with acute, sharp and rapid onset pain.

Answer 14

A-d fibers

Question 15

Which nerve fibers are nonmyelinated, slow transmission. Involved with chronic, dull and aching pain

Answer 15

C-fibers

Question 16

Where do afferent peripheral nerves enter spinal cord?

Answer 16

Dorsal roots (grey matter) and ascend via spinothalamic and spinoreticular tracts to brain

Question 17

What are two excitatory substances?

Answer 17

Substance P (NK1 receptor) and glutamate (NMDA)

Question 18

What are examples of inhibitory substances?

Answer 18

GABA and endogenous opioids

Question 19

What kind of pain is transmitted through the spinothalamic tract?

Answer 19

Superficial pain- terminates at the thalmus

Question 20

What kind of pain is transmitted through the spinoreticular tract?

Answer 20

Deep and visceral pain

Question 21

What is a systemic consequence of unmanaged pain?

Answer 21

Stress response (tachy, hypertension, increased cardiac workload, atelectasis, hyperventilation, hypoxia, nausea, ileus and urinary retention)

Question 22

T/F: Pathologic pain is adaptive

Answer 22

FALSE

Question 23

Pain evoked by stimulus not normally causing pain is known as what?

Answer 23

Allodynia

Question 24

Increased/exaggerated response to stimulus that is normally painful is known as what?

Answer 24

Hyperalgesia

Question 25

What is the difference of primary and secondary hyperalgesia?

Answer 25

Primary: at site of injury
Secondary: occurs in surrounding tissues

Question 26

Describe peripheral sensitization

Answer 26

increase in activity, excitability, and responsiveness leading to primary hyperalgesia

Question 27

Summation of painful stimulation in spinal cord-mediated by C-fibers and contributes to central sensitization

Answer 27

Windup pain

Question 28

What is the mechanism of windup pain?

Answer 28

Removes Mg block on NMDA receptor allowing receptor to be available for glutamate binding and increase pain transmission

Question 29

Increase in nerve excitability and responsiveness in the CNS leading to primary and secondary hyperalgesia and allodynia.

Answer 29

Central sensitization

Question 30

T/F: Central sensitization increases dorsal horn excitability and decreased inhibition at spinal cord level (decreased GABA)

Answer 30

TRUE

Question 31

What does central sensitization result in?

Answer 31

Hyperalgesia, allodynia, spontaneous pain and pain memory

Question 32

What is a term for loss of sensitivity to pain?

Answer 32

Analgesia

Question 33

What is the advantage of physiologic pain?

Answer 33

Prevents tissue damage

Question 34

Which pain fiber would most likely involved in transmitting sharp, fast pain?

Answer 34

A-d fibers; C-fibers are responsible for slow chronic pain

Question 35

What kind of pain would be created by a broken bone, brachial plexus avulsion, gastric dilation and hip dysplasia?

Answer 35

Broken bone: somatic pain and inflammatory pain
Brachial plexus: neurological pain-acute
GDV: visceral acute pain
Hip dysplasia: chronic inflammation and somatic pain

Question 36

What are the major excitatory and inhibitory neurotransmitters involved with pain transmission?

Answer 36

Glutamate and substance P are excitatory and GABA is inhibitory

Question 37

What are the physiologic consequences of untreated/chronic pain

Answer 37

Stress response, immunosuppression, exhaustion, GI CV respiratory effects and HYPERglycemia

Question 38

What strategies could be used to prevent peripheral sensitization? NSAIDs/topical anesthetic.

Answer 38

Central sensitization: ketamine and all other drugs acting on spinal cord

Question 39

Does general anesthesia prevent either peripheral or central sensitization?

Answer 39

No, all of these things are happening, your patient is just unaware-which is why it is still important to give analgesics to your patients