230: Pain

Question 1

Cause of Congenital Insensitivity to Pain

Answer 1

sodium channel mutations

Question 2

list some inflammatory chemical pain stimulaters

Answer 2

histamine, bradykinin, prostaglandin

Question 3

name the thermal pain receptor

Answer 3

capsaicin (TRPV1) ( temperatures above 43 degrees c.)

Question 4

where are Meissner’s Corpuscles

Answer 4

in the skin (stretch receptors)

Question 5

where are Pacinian Corpuscles

Answer 5

in the skin ( touch receptor)

Question 6

where are merkel discs?

Answer 6

in the skin ( mechanoreceptors, respond to pressure)

Question 7

where are Ruffini end organs?

Answer 7

in the skin (mechanoreceptor responds to pressure)

Question 8

Fast, mylinated nociceptor

Answer 8

A delta fibres

Question 9

unmylinated slow nociceptor

Answer 9

C-fibres

Question 10

activation of which receptor inhibits pain ( rub it better)

Answer 10

A beta ( block A delta fibre info via interneurone in the spinal cord) ( e.g. Man City GK broke neck can be seen rubbing neck while playing on).

Question 11

common local anaesthetic (blocks voltage gated Na channels)

Answer 11

lidocane

Question 12

common anticonvulsant/ mood stabiliser ( blocks voltage gated Na channel)

Answer 12

carbamazepine

Question 13

what do the descending pathways do?

Answer 13

modulate the ascending sensory pathway ( via endogenous opiods)

Question 14

what causes phantom limb pain?

Answer 14

sensory confusion because 2nd and 3rd order nociceptors are still there even though the primary one has been removed ( or never existed).
A beta afferents can sprout into the lamina and synapse on to the send order nociceptor.

The somatosensory cortex can also get rewired ( if arm is missing the nuclei for that are creeps into face and shoulder)

Question 15

list some opiates

Answer 15

morphine, codeine, heroin

Question 16

most potent analgesic metabotropic opioid receptor?

Answer 16

mu and delta (also most addictive)

Question 17

List some endogenous opioids and their roles

Answer 17

Endorphins ( reward), Enkephalins (delta receptor agonist…descending pathway inhibit sensory pathway), Dynorphins ( kappa receptor agonist)

Question 18

Cox - synthesised by and inhibited by?

Answer 18

synthesis = prostaglandins. inhibited by aspirin.

Question 19

What is substance P

Answer 19

neuropeptide dilates blood vessels and triggers histamine release

Question 20

what is bradykinin

Answer 20

neurotransmitter involved in chronic pain

Question 21

what is histamine

Answer 21

neurotransmitter involved in chronic pain

Question 22

what do NSAIDS target

Answer 22

inflammation

Question 23

hyperalgesis

Answer 23

stimulus hurts more than it should

Question 24

allodynia

Answer 24

stimulus hurts when it shouldn’t

Question 25

parasthesia

Answer 25

pain in the absence of stimulus

Question 26

referred pain: right shoulder

Answer 26

liver and gallbladder

Question 27

referred pain: retrosternal and left arm

Answer 27

heart

Question 28

referred pain of small intestine, colon, stomach and appendix

Answer 28

central abdo ( appendix moves to right flank when peritoneum becomes involved?)

Question 29

referred pain: flanks

Answer 29

ureters

Question 30

referred pain spine landmark: C3-4

Answer 30

diaphragm

Question 31

referred pain spine landmark: T1-4

Answer 31

heart

Question 32

referred pain spine landmark: T6-9

Answer 32

stomach

Question 33

referred pain spine landmark: T7-8

Answer 33

gall bladder

Question 34

referred pain spine landmark: T9-10

Answer 34

duodenum

Question 35

referred pain spine landmark: T10 right

Answer 35

appendix

Question 36

referred pain spine landmark: T10-12

Answer 36

reproductive organs

Question 37

referred pain spine landmark: L1-2

Answer 37

kidney, ureter

Question 38

process involved in stress induced analgesia (e.g. climber cutting own arm off to rescue himself)

Answer 38

Amygdala projections from cortex to periaquiductal grey opioid release.

Question 39

what does the substantial gelatinosa do?

Answer 39

area of the posterior horn where the 1st order neurones of the spinothalamic tract synapse

Question 40

what does the nucleus proprius do?

Answer 40

area of the posterior horn where the 1st order neurones of the spinothalamic tract synapse

Question 41

step one of WHO pain ladder

Answer 41

nonopoid (+/-adjuvants) (ibuprofen, naproxen, paracetamol)

Question 42

ibuprofen works how?

Answer 42

inhibits COX - COX 2 is the main enzyme to catalyse production of prostaglandins.

Question 43

paracetamol works how?

Answer 43

reduces central prostaglandin synthesis

Question 44

naproxen works how?

Answer 44

NSAID ( Cox inhibition)

Question 45

sterp 2 of the WHO pain ladder

Answer 45

weak opioid + non-opioid (+/- adjuvants) (weak opioids are codeine and dihydrocodeine)

Question 46

codeine works how?

Answer 46

opioid analgesic

Question 47

dihydrocodeine works how?

Answer 47

Fentanyl how does it wo

Question 48

COX 2 specific inhibitors

Answer 48

Celecoxib and Etoricoxib

Question 49

Tramadol side effects

Answer 49

reduces epileptic seizure threshold, hallucinations/ confusion, withdrawal issues, addiction abuse

Question 50

non-opioid properties of Tramadol

Answer 50

inhibits reuptake of norepinephrine and stimulates serotonin release.

Question 51

caution required when prescribing tramadol to someone on SSRIs, why?

Answer 51

tramadol increases Seratonin release therefore 'serotonin syndrome' risk - autonomic hyperactivity (enters - diarohea) , neuromuscular abnormality (tremor), mental status change (agitation, hypervigilance)

Question 52

Fentanyl how does it work?

Answer 52

opioid ( potent mu receptor agonist)

Question 53

Side effects of opioids

Answer 53

initial: nausea and vomiting, drowsiness, unsteaadiness, delirium. ongoing: constipation. Occasional: sweating, dry mouth, hallucinations, pruritis ( itchy skin),. longterm: endocrine/immune. rare/overdose: psychological depression/ respiratory depression

Question 54

opioid antagonist (in overdose)

Answer 54

naloxone

Question 55

WHO pain ladder step 3

Answer 55

strong opioid (fentanyl, morphine, oxycodone) plus non-opioid (=/- adjuvant)

Question 56

paracetamol overdose antidote?

Answer 56

N-acetyl cisteine and glutathione to mop up free radicals

Question 57

MST

Answer 57

morphine sulphate tablets!

Question 58

how do bisphoshonates work?

Answer 58

stop bone degradation via reduced osteoclast activity.

Question 59

how to anti epileptics work as analgesics?

Answer 59

neuropathic pain - reduce glutamate release at synapse e.g. gabapentin inhibits pre synaptic Ca channel ( if calcium doesn't go in glutamate doesn't get realised) carbamazepine - blocks Na channel presynaptically.

Question 60

Treatment of Painful Diabetic Peripheral Neuropathy (PDPN)

Answer 60

Duloxetine (serotonin noradrenaline reuptake inhibitor (SNRI)

Question 61

nociceptive pain originates where?

Answer 61

in the tissue

Question 62

neuropathic pain originates where?

Answer 62

from damaged nerves.