Pain

Question 1

Pain definition

Answer 1

Subjective sensation of nociceptive stimulus

Question 2

TRP acronym

Answer 2

Transient Receptor Protein

Question 3

TRP types

Answer 3

TRP v1
TRP M (‘M’ = menthol)

Question 4

TRP v1

Answer 4

Chilli pain receptors

Question 5

TRP M

Answer 5

Cold

Question 6

Pain nerve fibre classification

Answer 6

C fibres
A delta

Question 7

C nerve fibre qualities

Answer 7

Non-myelinated
Slower longer onset of pain

Question 8

A delta nerve fibre qualities

Answer 8

Myelinated -
Quicker shorter onset of pain

Question 9

Common pain nerve fibres in viscera

Answer 9

C

Question 10

Common pain nerve fibres in skin

Answer 10

A delta

Question 11

Pathway of pain signal - Pain cascade

Answer 11

Nerve ending impulse ->

Dorsal root ganglion (glutamate in synapse) ->

Decussates at level of spinal cord ->

Spinothalamic tract ->

Thalamus ->

Signal splits to multiple parts of the brain:
- Cortex
- Periaqueductal grey
- Nucleus Raphe Magnus
- Locus Coeruleus

Question 12

Excitatory synaptic neurotransmitter

Answer 12

Glutamate

Question 13

Inhibitory synaptic neurotransmitter

Answer 13

GABA

Question 14

Gate control theory of pain site

Answer 14

Substantia gelatinosa

Question 15

Nerve input to substantia gelatinosa

Answer 15

A delta pain fibre
A beta motor fibre
Periaqueductal grey via Nucleus Raphe Magnus
Locus coeruleus

Question 16

Location of periaqueductal grey

Answer 16

Around 3rd ventricle to base of brain stem

Question 17

Neurotransmitter for Nucleus Raphe Magnus

Answer 17

Serotonin

Question 18

Neurotransmitter for Locus Coeruleus

Answer 18

Noradrenaline

Question 19

Receptor present in substantia gelatinosa

Answer 19

NMDA

Question 20

NMDA receptor qualities

Answer 20

Ionotropic receptor (not g protein coupled)
Glutamatergic
Particularly permeable to Calcium ions (and Sodium)

Question 21

How does Magnesium inhibit NMDA receptor

Answer 21

Magnesium and 2+ charge (same as Calcium) but is larger in size so does not pass Magnesium

Electrochemical gradient attracts Magnesium but blocks receptor

Competes with calcium but does not permeate

Use dependant blockade of NMDA receptors

Question 22

Action of intravenous Lidocaine at non cardiotoxic doses

Answer 22

NMDA receptor antagonist

Question 23

Ketamine mode of action

Answer 23

NMDA receptor antagonist

Question 24

Methods to reduce pain in peripheral nerve tissue

Answer 24

Regional block
Reduce size of incisions
Anti-inflammatories (NSAIDs, Dexamethasone)

Question 25

Drugs

Question 26

Types of opioid receptors

Answer 26

Mu opioid receptor
Kappa opioid receptor
Delta opioid receptor

Question 27

Opioid receptor qualities and action

Answer 27

Pre-synaptic G coupled metabotropic receptor
Gi (inhibitory)
Reduces cyclic AMP action
Reduces voltage gated calcium channel action

Question 28

Location of action of opioid receptors

Answer 28

Spinal level - receptors in substantia gelatinosa

Further in pain cascade - inhibitory action on locus coeruleus

Question 29

Mode of action of clonidine

Answer 29

Alpha 2 receptor agonist

Question 30

Effects of clonidine

Answer 30

Anxiolytic - reduced sympathetic drive

Analgesia - not 100% know but possible reduced noradrenaline action (eg from locus coeruleus

Question 31

Analgesia option which effects Nucleus Raphe Magnus and Locus coeruleus

Answer 31

Tricyclic antidepressants - Amitriptyline
Duloxetine

Mixed SNRI effects

Question 32

Plane block definition

Answer 32

Anaesthetise ‘plane’ / area rather than specific nerve

More conducive to catheter insertion as less risk than when placed directly to nerve

Question 33

Approach to regional block pain calls

Answer 33

Check block area with ethyl chloride spray
Does level of block need to increase (more volume, lower concentration)
Does level of analgesia need to increase (less volume, higher concentration)