Overview of Pain Medication

Question 1

Is pain a stimulus?

Answer 1

No, it is a sensory and emotional experience

Question 2

Describe the basic four stages of pain sensation

Answer 2

1. Periphery
   Nociception
   Transmission to spinal cord (first order)
2. Spinal Cord
   Processing
   Transmission to the brain (thalamus, secone order)
3. Brain
   Perception, learning, response
4. Modulation
   Descending tracts

Question 3

Briefly define nociception

Answer 3

The detection of tissue damage by specialised transducers connected to A-delta and C fibres

Question 4

Where are the cell bodies of primary afferent neurons?

Answer 4

Dorsal root ganglion

Question 5

Where do first order afferent neurons synapse?

Answer 5

In the spinal cord at the level at which they enter

Question 6

Are A-alpha and A-beta fibres myelinated?

Answer 6

Yes

Question 7

Are A-delta fibres myelinated?

Answer 7

Yes but lightly

Question 8

Are C fibres myelinated?

Answer 8

No

Question 9

In what areas of the spinal cord do the primary afferent neurons synapse?

Answer 9

Rexed lamina 2 and 5 of the ventral horn of the grey matter, the Substantia Gelatinosa

Question 10

From where in the spinal cord do second order afferent neurons travel upwards to the brain?

Answer 10

The posterioventral part of the cord on the contralateral side of entry in the white matter spinothalamic tracts

Question 11

Where in the brain does pain perception occur?

Answer 11

The somatosensory cortex

Question 12

Are the receptive neurons in the spinal dorsal column nociceptive specific?

Answer 12

Yes

Question 13

Is the threshold of the pain sensing neurons in the spinal dorsal column high or low?

Answer 13

Low

Question 14

What is the major ascending tract for nociception?

Answer 14

Spinothalamic tract

Question 15

With which areas is the thalamus connected?

Answer 15

Cortex
Limbic system
Brainstem

Question 16

Where in the spinal cord does descending efferent information travel?

Answer 16

In the periaqueductal grey matter

Question 17

What is allodynia?

Answer 17

A decreased threshold for nociceptive response

Question 18

What is hyperalgesia?

Answer 18

An exaggerated response to normal and supranormal stimuli

Question 19

What causes spontaneous pain?

Answer 19

Spontaneous activity in the nerve fibres

Question 20

What is central sensitization?

Answer 20

The response of second order neurons in the CNS to normal input both noxious and non-noxious

Question 21

What are the three main components of central sensitization?

Answer 21

Wind-up
Classical
Long-term potentiation

Question 22

Describe the wind-up component of secondary sensitization

Answer 22

This involves only activated synapses and is dependent on homosynaptic, it results in a progressive increase in the response of the neurons
It manifests over the course of the stimuli and terminates with stimuli

Question 23

Describe the classical component of secondary sensitization

Answer 23

This involves the opening of new synapses that depend on heterosynaptic activity. When the appropriate stimuli there is an immediate response that outlasts the initial stimuli duration

Question 24

Describe the long-term potentiation component of secondary sensitization

Answer 24

This involves mainly the activated synapses - persistent strengthening of synapses based on recent patterns of activity and occurs primarily for very intense stimuli, often chronic pain

Question 25

What are the criteria for chronic pain?

Answer 25

Pain for 3-6 months or more
Pain beyond expected period of healing
Usually has no protective function
Degrades health and function

Question 26

Outline acute pain

Answer 26

Usually obvious tissue damage
increased 
Increased nervous system activity
Pain response upon healing
Serves a protective function

Question 27

Is a noxious stimulus always present in acute pain?

Answer 27

Yes

Question 28

Is a noxious stimulus always present in chronic pain?

Answer 28

Not essential

Question 29

Does chronic pain have any purpose?

Answer 29

No

Question 30

Is acute pain pathological or physiological?

Answer 30

Physiological

Question 31

Is chronic pain pathological or physiological?

Answer 31

Pathological

Question 32

What are two main forms of ‘pain’?

Answer 32

Nociceptive

Neuopathic

Question 33

Describe neuropathic pain

Answer 33

Pain initiated or caused by a primary lesion or dysfunction in the somato-sensory nervous system
Almost always a chronic neuropathic condition
Responds poorly to conventional analgesics

Question 34

Describe nociceptive pain

Answer 34

A sensory experience that occurs when specific peripheral sensory neurons (nociceptors) respond top noxious stimuli
The pain in usually localized at the site of the injury and typically resolves when the damaged tissue heals
Can be chronic e.g. osteoarthritis
Tends to respond to conventional analgesics

Question 35

How do pain and nociception differ?

Answer 35

Pain is the subjective phenomena in response to the physiological process that is nociception

Question 36

What stage of nociception do NSAIDs, ice and rest target?

Answer 36

Transduction

Question 37

What stage of nociception do nerve blocks, opioids, anticonvulsants and some forms of surgery target?

Answer 37

Transmission

Question 38

What stage of nociception do education, cognitive therapy, distraction, relaxation etc target?

Answer 38

Perception

Question 39

What stage of nociception do placebos, opioids, antidepressants, and surgical spinal cord stimulation target?

Answer 39

Descending modulation