Pain

Question 1

What is the definition of pain

Answer 1

an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such danger

Question 2

what is the classification of acute pain

Answer 2

short term, less than 12 weeks duration

Question 3

what is the classification of chronic pain

Answer 3

continuous long term pain, more than 12 weeks duration OR pain tat persists after the time that healing would have been theought to have occurred after trauma/ surgery

Question 4

what are the divisions of chronic pain

Answer 4

cancer pain and chronic non-cancer pain

Question 5

what are the 3 parts of coping with chronic pain

Answer 5

Pacing, Planning, Prioritising

Question 6

what is a flare up (in terms of pain)

Answer 6

increase in patient’s usual pain; not a new pain sensation

Question 7

what is the definition of nociceptive pain

Answer 7

pain that arises from actual or threatened damage to non-neural tissue and is due to the activation of nociceptors
- used in conjunction with a normally functioning somato-sensory system

Question 8

what is the definition of neuropathic pain

Answer 8

pain arising as a direct consequence of a lesion or disease of the somato-sensory system

Question 9

what does allodynia mean

Answer 9

pain due to stimulus that does not normally provoke pain

Question 10

what does dysesthesia mean

Answer 10

an unpleasant abnormal sensation, whether spontaneous or evoked

Question 11

what does hyperalgesia mean

Answer 11

increased pain from a stimulus that normally provokes pain

Question 12

what does hypoalgesia mean

Answer 12

diminished pain in response to normally painful stimulus

Question 13

what does hypoesthesia mean

Answer 13

dimisinished sensitivity to stimulation, excluding special senses

Question 14

describe the path of 1st order/ primary afferent neurones of the pain response

Answer 14

enter spinal cord through spinal nerve or brainstem through CN V, ipsilateral to peripheral receptor
Remain ipsilateral and synapse with 2nd order neurones in the CNS

Question 15

describe the path of 2nd order neurones in the pain responses

Answer 15

cell body located in spinal cord/ brainstem

axons decussate to other side of CNS and ascend to thalamus where it terminates

Question 16

describe the path of 3rd order neurones in the pain response

Answer 16

cell body located in thalamus

axon projects to somatosensory cortex in post central gyrus of parietal lobe

Question 17

what are nociceptors

Answer 17

sensory neurones found in any area of body that can sense pain either externally or internally

Question 18

where are the cell bodies of nociceptors

Answer 18

dorsal root ganglion (body) or trigeminal ganglion (face/ head/ neck)

Question 19

what can cause hyperalgesia

Answer 19

presence of tissue damage/ bradykinin/ prostaglandin E2 can reduce nociceptive AP threshold so increase sensitivity to stimuli

Question 20

what is the modality of nociceptors generally

Answer 20

poly-modal; thermal/ chemical/ mechanical

Question 21

what are the 2 type of afferent fibres associated with the pain response

Answer 21

alpha delta fibres and c fibres

Question 22

describe alpha delta fibres

Answer 22

thinly myelinated
carry touch, pressure, temperature, FAST pain information
small diameter; 1-5 microns
medium conduction speed; 5-40m/s

Question 23

describe c fibres

Answer 23

unmyelinated
carry SLOW pain, temperature, touch, pressure, itch, postganglionic autonomic fibres information
smallest diameter - 0.2-1.5 micrometers
slowest conduction speed; 0.5-2m/s

Question 24

what sort of neurones are a delta and c fibres

Answer 24

1st order

nociceptors

Question 25

where do 1st order neurons synapse with 2nd order neurones in the pain pathway

Answer 25

substantia gelatinosa in grey matter of dorsal horn of spinal cord

Question 26

describe a delta terminals

Answer 26

release glutamate as neurotransmitter | - fast acting

Question 27

describe c fibre terminals

Answer 27

release glutamate and substance P as neurotransmitter | - slow acting, involved in mediation of dull aching pain

Question 28

what does the spinothalamic tract carry

Answer 28

pain, temperature, crude touch from body

Question 29

where does the spinothalamic tract enter the spinal cord

Answer 29

Lissauer's fasciculus

Question 30

what does the trigemino-thalamic tract carry

Answer 30

pain, temperature, crude touch from face/ head/ neck

Question 31

where does the trigemino-thalamic tract receive contributions from

Answer 31

CN 5, 7, 10, 12

Question 32

what does the lateral spinothalamic tract carry

Answer 32

pain and temperature

Question 33

what does the anterior spinothalamic tract carry

Answer 33

crude touch

Question 34

where do the spinothalamic/ trigemino-thalamic tracts terminate

Answer 34

ventral posterior lateral nucleus of thalamus

Question 35

what tracts are involved in the pain response

Answer 35

spinothalamic and trigemino-thalamic

Question 36

describe dorsal root ganglion

Answer 36

on dorsal root composed of cell bodies of nerve fibres that are sensory - afferent pseudo-unipolar neurons 1st order neurons

Question 37

what are the functions of the nuclei in the thalamus

Answer 37

relay and association

Question 38

what is the role of the insula

Answer 38

where degree of pain is judged - contributes to subjective aspect of pain perception

Question 39

where is the insula

Answer 39

within brain via sylvian fissure

Question 40

where is the cingulate gyrus

Answer 40

medial aspect of cerebral hemispheres

Question 41

what is the role of the cingulate gyrus

Answer 41

linked with limbic system; involved in emotional response to pain and associated with emotion forming/ processing learning and memory

Question 42

what the periaqueductal grey

Answer 42

grey matter around aqueduct in the midbrain

Question 43

where does the periaqueductal grey receive input from

Answer 43

somatosensory cortex (Brodmann 1,2,3)

Question 44

what pathway is the periaqueductal grey involved in

Answer 44

descending pain pathway

Question 45

when is the periaqueductal grey activated and why

Answer 45

activated in situations of high stress and contributes to modulation of afferent noxious transmission has high concentration of opioid receptors and endogenous opioids

Question 46

where does the periaqueductal grey project to

Answer 46

dorsal horn

Question 47

what happens when the periaqueductal grey is activated

Answer 47

opioid receptors are activated leading to reduction in pre-synaptic neuronal sensitivity so reducing substance P release so reducing pain sensation - less impulses travel up 1st/2nd/3rd order neurons to somatosensory cortex so less pain felt

Question 48

what do opioids do

Answer 48

bind to opioid receptors in periaqueductal grey so reducing pre-synaptic neuronal sensitivity -result in profound analgesia

Question 49

what is the definition of analgesia

Answer 49

selective suppression of pain without effects on consciousness/ other sensation

Question 50

what is the definition of anaesthesia

Answer 50

uniform suppression of pain | - sometimes consciousness is lost e.g. general anaesthetic

Question 51

what is the Melzack-Wall Pain Gate theory

Answer 51

states that non-painful input closes the gate to painful input - preventing pain sensation from travelling to the somatosensory cortex to be perceived and thus felt

Question 52

what are some treatments for pain

Answer 52

analgesics acupuncture exercise hypnotherapy

Question 53

what is substance P

Answer 53

Peptide neurotransmitter involved in pain transmission -also a vasodilator remains bound to receptors for longer time so transmits long lasting pain