Chapter 8

Question 1

Neuropathic pain

Answer 1

pain arising as a direct consequence of a lesion or disease affecting the somatosensory system

Question 2

Paresthesia:

Answer 2

painless abnormal sensation in the absence of nociceptor stimulation

Question 3

Dysesthesia:

Answer 3

unpleasant abnormal sensation, either evoked or spontaneous

Question 4

Alloydynia:

Answer 4

pain evoked by a stimulus that normally would not cause pain

Question 5

Secondary hyperalgesia:

Answer 5

excessive sensitivity to stimuli that are normally mildly painful in uninjured tissue

Question 6

What are the mechanisms responsible for neuropathic pain:

Answer 6

1. ectopic foci
2. ephaptic transmission
3. central sensitization
4. structural reorganization

Question 7

What is ectopic foci?

Answer 7

When myelin is damaged, signals from the exposed axon stimulate excessive production of mechanosensitive and chemosensitive ion channels, producing abnormal sensitivity to mechanical/chemical stimuli

Question 8

What is ephaptic transmission?

Answer 8

Occurs in demyelinated regions due to a lack of insulation between neurons. An action potential in one neuron may induce an action potential in another neuron.

Question 9

What is central sensitization?

Answer 9

is excessive responsiveness of central neurons
develops in response to ongoing nociceptive input, and yet persists after the peripheral injury has healed.
In central sensitization, the central neurons produce disproportionate neural output to incoming nociceptive signals

Question 10

What is structural reorganization?

Answer 10

Structural changes in the dorsal horn include withdrawal of C-fiber axon terminals from the dorsal horn and growth of Aβ-fiber axons into regions of the spinal cord that normally receives only C-fiber terminals

Question 11

Where can neuropathic pain arise?

Answer 11

periphery
CNS in response to deafferentation
dorsal horn

Question 12

What does complete nerve resection result in?

Answer 12

results in a lack of sensation from that nerve’s receptive field

Question 13

What does partial damage result in?

Answer 13

allodynia and sensations similar to an electric shock

Question 14

What is the central response to deafferentation?

Answer 14

1. phantom pain
2. central pain; SCI, CVA, MS
3. small fiber neuropathy

Question 15

What is central pain caused by?

Answer 15

caused by a lesion of the CNS and is usually localized to the area of the body deafferented by the lesion

Question 16

What does neuropathic pain refer to?

Answer 16

burning, shooting, aching, freezing, or tingling pain

Question 17

What are the conditions that involve disturbance of top down regulation of pain?

Answer 17

1. fibromyalgia
2. episodic tension-type headache
3. migraine
4. chronic whiplash-associated disorder

Question 18

What is fibromyalgia?

Answer 18

abnormal processing of pain information, resulting in the perception of pain without noxious stimuli to the nervous system.

Question 19

What is treatment for fibromyalgia?

Answer 19

aquatic therapy with or without exercise

Question 20

Criteria for ETTH (episodic tension-type headache)

Answer 20

• mild to moderate pain, usually bilateral
• lasting 30 mins to 7 days
• not aggravated by physical activity
• not associated with nausea or vomitting

Question 21

What is the mechanism for ETTH?

Answer 21

supersensitivity to nitric oxide which sensitizes the nociceptive pathways in the CNS.

Question 22

What are the characteristics of migraine?

Answer 22

• unilateral location
• pulsating quality
• severity interfering with daily activities
• aggravation from routine physical activities

Question 23

Complex regional pain syndrome:

Answer 23

involves the somatosensory, autonomic, and motor systems.

Question 24

Chronic low back pain syndrome:

Answer 24

involves muscle guarding, disuse, and abnormal movements

Question 25

What are the three D of chronic pain?

Answer 25

distress
disuse
disability