pain mechanism and management

Question 1

nociception

Answer 1

perception of injurious stimuli

Question 2

factors influencing pain perception

Answer 2

cognition
mood
context
genetics
chemical+structural
injury

Question 3

types of pain

Answer 3

nociceptive
neuropathic
acute
chronic

Question 4

neuropathic pain

Answer 4

chronic maladaptive pain after TBI

Question 5

how long does chronic pain last

Answer 5

3 months+

Question 6

which type of pain is often resistant to analgesics

Answer 6

neuropathic

Question 7

how is pain intensity conveyed by nocioceptors

Answer 7

frequency coding - freq of discharge

Question 8

what factors increase speed of transmission along an axon

Answer 8

increased axon diameter
myelination

Question 9

which axons convey pain

Answer 9

A delta
C

Question 10

what do A delta fibres convey

Answer 10

pain
temperature

Question 11

what do C fibres convey

Answer 11

pain
temperature
itch
chemoreception

Question 12

which fibres convey first pain and second pain

Answer 12

first - A delta
second - C

Question 13

what do TRP and TRPM8 channels on thermal nociceptors transduce

Answer 13

TRP - heat
TRPM8 - cold

Question 14

what do thermal nociceptors respond to

Answer 14

heat and cold

Question 15

what do mechanical nociceptors respond to

Answer 15

excess pressure
mechanical deformation

Question 16

what do chemical nociceptors respond to

Answer 16

inflammatory mediators

Question 17

inflammatory mediators

Answer 17

histamine
prostaglandins
proteases
bradykinins
serotonin
ATP
H+
potassium

Question 18

what type of receptor are most nociceptors

Answer 18

polymodal - respond to temp+pressure+mechanical deformation+inflammatory mediators

Question 19

how does capsaicin prevent response from nociceptors

Answer 19

overstimulates receptor

Question 20

what does substance P do

Answer 20

attracts histamine releasing cells
dilates blood vessels
alters cell signalling pathways to modulate pain perception

Question 21

erythromelalgia

Answer 21

neuropathy characterised by recurrent burning pain, warmth, and redness of extremities

Question 22

what causes primary erythromelalgia

Answer 22

Autosomal dominant genetic mutation causing hypersensitive nav1.7 channel

Question 23

what part of the brain does the spinothalamic tract transmit to

Answer 23

thalamus

Question 24

where does the spinothalamic pathway decussate

Answer 24

second neurone in spinal cord immediately after synapse with primary afferent

Question 25

where does the DCML pathway decussate

Answer 25

second neurone at medial lemniscus of medulla

Question 26

which part of the cortex controls the sensory-discriminative aspect of pain

Answer 26

somatosensory cortex

Question 27

which part of the cortex controls the affective-motivational aspect of pain

Answer 27

anterior cingulate cortex and insular cortex

Question 28

discriminative pain pathways

Answer 28

spinothalamic tract trigemino-thalamic tract

Question 29

phantom pain

Answer 29

feeling pain where a missing body part should be

Question 30

what causes phantom pain

Answer 30

mal-adaptive plasticity

Question 31

what causes referred pain

Answer 31

primary afferent from skin and primary afferent from viscera converge on same secondary neurone

Question 32

why does rubbing an injury reduce pain

Answer 32

Melzack and Walls gate theory of pain - free nerve endings in the deeper layers of the skin respond to touch by inhibiting spinal transmission of pain signals from the body to the brain

Question 33

areas of the brain involved in descending pain modulation

Answer 33

Anterior cingulate cortex hypothalamus nucleis cuniformis periaqueductal grey Dorsolateral pontine tegmentum rostral ventromedial medulla

Question 34

where are cannabinoid receptors present

Answer 34

pain pathways at peripheral and central levels CNS GI Bones Immune system Muscles

Question 35

where are endocannabinoids synthesised

Answer 35

membranes of neurones and other nervous cells

Question 36

cannabinoid receptors

Answer 36

CB1 CB2

Question 37

do cannabinoids increase or decrease NT release

Answer 37

decrease

Question 38

release of which NTs are inhibited by activation of cannabinoid receptors

Answer 38

L-glutamate GABA noradrenaline dopamine serotonin ACh

Question 39

CNS structures activated by nociceptive stimuli

Answer 39

spinal cord thalamus somatosensory cortex anterior cingulate cortex insula amygdala prefrontal cortex hippocampus