pain

Question 1

define pain

Answer 1

An unpleasant sensory & emotional experience associated with actual
potential tissue damage, or described in terms of such damage

Question 2

does pain require actual tissue damage

Answer 2

no
it is not the same as nociception
and is not proportional to damage

Question 3

define acute pain

Answer 3

Short term pain of less than 12 weeks

can usually be explained and treated

Question 4

define chronic pain

Answer 4

Continuous long term pain of more than 12 weeks

medical investigations may not provide diagnosis

treatment aimed at relieving pain not curing it

widespread effect on life

Question 5

define Nociceptive pain

Answer 5

Pain that arises from actual or threatened damage to nonneuronal tissue and is due to the activation of nociceptors

Question 6

define Neuropathic pain

Answer 6

Pain initiated or caused by a primary lesion/dysfunction of the nervous system e.g. due to spinal nerve root compression

Question 7

what are the neurones within the pain pathway

Answer 7

Within the pain pathway there are 3 orders of neurones that carry action potentials signalling pain:

first order neurones

second order neurones

third order neurones

Question 8

where are the 3 pain neurones

Answer 8

between the sensory receptor
located in the periphery and the perception of sensation at the level of the cerebral cortex

Question 9

course of first order/primary afferent neurone

Answer 9

Enters the spinal cord through a spinal nerve, or the brainstem
through the trigeminal nerve, on the same side of the body
(ipsilaterally) as the peripheral receptor is located
* Remains ipsilateral and synapses with a second order neurone
within the CNS

Question 10

course of second order neurone

Answer 10

Cell body is located in the spinal cord/brainstem (exact location
depends where sensory receptor is, i.e. brainstem if the face etc.)
* Its axons CROSS over (decussates) to the other side of the CNS and
ascends to the thalamus where it terminates

Question 11

course of third order neurone

Answer 11

Cell body is located within the thalamus and its axon projects to the
somatosensory cortex - located in the post central gyrus of the
parietal lobe of the cerebral hemisphere

Question 12

what are nociceptors

Answer 12

Sensory neurons that are found in any area of the body that can sense pain
either externally or internally:
* Externally: skin, cornea, mucosa
* Internally: viscera, joints, muscles & connective tissue etc

Question 13

where do cell bodies of nociceptors reside

Answer 13

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

Question 14

what happens when there is tissue damage

Answer 14

bradykinin & prostaglandin E2 - both reduce the nociceptive action potential threshold thereby
increasing their sensitivity to stimuli - known as hyperalgesia

Question 15

why are most nociceptors polymodal

Answer 15

they contain multiple receptors and thus respond to various combinations of the stimuli - thermal/chemical/mechanical pain

Question 16

what are the types of afferent fibres

Answer 16

1. Alpha delta fibres
2. C fibres

Question 17

describe alpha delta fibres

Answer 17

• Thinly myelinated
• Carries; touch, pressure, temperature & FAST pain information
• Small diameter (1-5 micrometers)
• Conduction speed is medium (5-40m/s)

Question 18

describe C fibres

Answer 18

• Unmyelinated
• Carries; SLOW pain, temperature, touch, pressure, itch,
  postganglionic autonomic fibres information
• Smallest diameter (0.2-1.5 micrometers)
• Conduction speed is the slowest (0.5-2m/s)

Question 19

where do Nociceptors (A delta & C fibres - first-order neurones) synapse with secondary afferent neurones (second order)

Answer 19

in the GREY MATTER of the
DORSAL HORN of the spinal cord (which is divided up into Rexed laminae)

Question 20

what do the A delta (primary afferent neurone) terminals release

Answer 20

they release GLUTAMATE (FAST ACTING) as their neurotransmitter

Question 21

what do the C fibres (primary afferent neurone) terminals release

Answer 21

GLUTAMATE &
SUBSTANCE P (SLOW ACTING - involved in the mediation of dull aching
pain) as their neurotransmitters

Question 22

where do first order/primary afferent neurones transmit information into

Answer 22

into the dorsal root ganglion where they synapse with second order neurones at the substantia gelatinosa

Question 23

where do second order neurones transmit the pain impulse up

Answer 23

• SPINOTHALAMIC TRACT (carries pain,temperature & crude touch
  information from the BODY) - enters the spinal cord at LISSAUER’S
  FASCICULUS
• Trigemino-thlamic tract (carries pain, temperature & crude touch
  information from the face/head/neck):
  - First order neurones enter at the pons and then descend to the
  medulla forming the spinal trigeminal tract
  - Receives contributions from the trigeminal, facial, vagus &
  glossopharyngeal nerves

Question 24

where do spinothalmic tract and trigemino thalmic tract terminate

Answer 24

at the thalamus (ventral posterior lateral nucleus)

Question 25

what is the spinothalamic tract divided into

Answer 25

the anterolateral tract
which consists of;
* Lateral spinothalamic tract (pain & temperature)
* Anterior spinothalamic tract (crude touch)

Question 26

where does the axon decussate

Answer 26

a few levels ABOVE the site of injury

Question 27

course of third order neurones

Answer 27

from the thalamus to terminate in the
SOMATOSENSORY CORTEX on the POST-central gyrus of the parietal
lobe

Question 28

what can pain affecr

Answer 28

ability to work
acitvities
relationships
self confidence
sleep
concentration
mood

Question 29

3 Ps to help pain

Answer 29

pacing
prioritising
planning

Question 30

what is pacing

Answer 30

limiting the time spent on an activity to prevent marked increases in pain, and keeping to a regular amount of activity to prevent the problems of too much rest

planning activity rather than doing things according to how you feel

taking frequent breaks

Question 31

what is planning

Answer 31

thinking about when and how activities will be done

making sure they are spread out

balance essential and non essential activities

Question 32

what is prioritising

Answer 32

making choices about what is done

Question 33

impact of muscle tension on pain

Answer 33

can make pain worse

is a natural reaction for muscles to tense in anticipation of pain and when pain is experiences

Question 34

what can frequent and long muscle tension cause

Answer 34

• aches, discomfort, tiredness
• simple movements become slow eg walking
• can become normal so you become physically tense without being aware of it

Question 35

impacts of relaxation

Answer 35

changes experience of pain
helps manage pain and feel more in control
useful distraction
helps deal with stress

Question 36

what is a flare up

Answer 36

an increase in a patients usual pain and not to new pain sensations
can occur quickly, out of the blue or gradually over time