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Flashcards in Chapter 8 Deck (25):
1

Neuropathic pain

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

2

Paresthesia:

painless abnormal sensation in the absence of nociceptor stimulation

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Dysesthesia:

unpleasant abnormal sensation, either evoked or spontaneous

4

Alloydynia:

pain evoked by a stimulus that normally would not cause pain

5

Secondary hyperalgesia:

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

6

What are the mechanisms responsible for neuropathic pain:

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

7

What is ectopic foci?

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

8

What is ephaptic transmission?

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.

9

What is central sensitization?

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

10

What is structural reorganization?

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

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Where can neuropathic pain arise?

periphery
CNS in response to deafferentation
dorsal horn

12

What does complete nerve resection result in?

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

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What does partial damage result in?

allodynia and sensations similar to an electric shock

14

What is the central response to deafferentation?

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

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What is central pain caused by?

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

16

What does neuropathic pain refer to?

burning, shooting, aching, freezing, or tingling pain

17

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

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

18

What is fibromyalgia?

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

19

What is treatment for fibromyalgia?

aquatic therapy with or without exercise

20

Criteria for ETTH (episodic tension-type headache)

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

21

What is the mechanism for ETTH?

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

22

What are the characteristics of migraine?

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

23

Complex regional pain syndrome:

involves the somatosensory, autonomic, and motor systems.

24

Chronic low back pain syndrome:

involves muscle guarding, disuse, and abnormal movements

25

What are the three D of chronic pain?

distress
disuse
disability