Pain Management

Question 1

is chronic pain recognised as a chronic disease?

Answer 1

yes

Question 2

Pain sensation pathway?

Answer 2

stimulus on skin > A delta and C fibres > glutamate and substance P released onto laminae 1 and 5 > fibres travel to thalamus > fibres travel to somatosensory cortex

Question 3

emotional/affective pathway of pain?

Answer 3

fibres from laminae 1 and 5 > parabrachial > amygdala hypothalamus > attention

Question 4

what causes pain after injury?

Answer 4

peripheral tissue injury changes nervous system in 2 ways

• peripheral sensitisation (reduction in threshold of peripheral afferent nociceptors)
• central sensitisation (increased excitability of spinal neurones, rewiring in spinal cord, changes in brain)

Question 5

chronic regional pain syndrome?

Answer 5

chronic pain in one limb lasting over 6 months

unknown cause, probably genetic component

Question 6

features of chronic pain syndrome?

Answer 6

allodynia
hyperalgesia
swelling
blue/red/white areas
hair and nail changes
osteopenia (pre osteoporosis)

Question 7

2 main categories of pain?

Answer 7

nociceptive (normal reaction to painful stimulus)
neuropathic (nervous system behaving abnormally)
others exist and can also be mixed

Question 8

description of neuropathic pain?

Answer 8

burning
shooting
tingling
sensitivity

Question 9

2 main features of neuropathic pain?

Answer 9

allodynia and hyperalgesia

Question 10

common causes of neuropathic pain?

Answer 10

shingles
post herpetic neuralgia
surgery
trauma
diabetic neuropathy
amputation

Question 11

how is neuropathic pain managed biologically?

Answer 11

tricyclic antidepressants (amitriptyline)
anticonvulsants (gabapentin, pregabalin)
opioids
NMDA antagonists (Ketamine)
sodium channel blockers (lignocaine)
capsaicin
GABA agonists (baclofen)

Question 12

what drugs are more often used in children?

Answer 12

topical levomenthol and capsaicin
lidocaine patch
tricyclics (amitriptyline)
gabapentin/pregabalin

Question 13

what can commonly cause chronic pain in cancer patients?

Answer 13

post surgery
chemo induced (peripheral neuropathies)
chronic graft vs host disease
radiation induced pain
hormonal therapy and arthralgias

Question 14

what procedures can be used in chronic pain?

Answer 14

lidocaine infusions
epidural steroids
facet denervation after test
stellate ganglion block
guanethidine block

Question 15

how are genetics involved in chronic post surgical pain?

Answer 15

40-50% inherited
SCN9A may be involved
- no pain if absent
- increased pain if abnormal

Question 16

who is most likely to progress to chronic post surgical pain?

Answer 16

may be related to childhood anxiety, depression and parental catastrophising
more severe post op pain = more likely to become chronic

Question 17

chronic pain in amputation?

Answer 17

immediate amputation = less likely to have chronic pain than delayed amputation

Question 18

opiates are more useful in which category of pain?

Answer 18

nociceptive

not as much in neuropathic

Question 19

side effects of long term opiate use?

Answer 19

hormonal (adrenal, libido)
immunomodulation
hyperalgesia (OIH)