S17+18 Pain Flashcards

1
Q

How are nociceptors sensitised?

A

Tissue damage and inflammation triggers the release of prostaglandins, bradykinin and histamine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which type of fibres carry nociceptive information?

A

Unmyelinated C fibres - polymodal.

Aδ fibres - thermal and mechanical.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Differentiate between first and second pain.

A

1st: Aδ. Sharp, easily localised, rapid, short, mechanical/thermal.
2nd: C fibres. Dull ache, poorly localised, slow onset, persistent. Polymodal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the spinal connections of nociceptive axons?

A

Cell bodies in dorsal root ganglion. Up/down short distance in Zone of Lissauer. Synapse onto neurones in lamina I + II : substantia gelatinosa.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which neurotransmitters are used by pain afferents?

A
Glutamate.
Substance P (most dense in superficial dorsal horn, receptor: NK1).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the three ascending pain pathways?

A

Lateral spinothalamic tract.
Spinoreticulothalamic tract.
Anterior spinothalamic tract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is dissociated sensory loss?

A

Touch, kPa, vibration + proprioception lost on the same side.
Pain lost on opposite side.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is pain and temperature info carried from the face?

A

Trigeminal system. Small afferents descend in spinal trigeminal tract to brain stem. Synapse in pars caudalis, ascend contra laterally in trigeminothalamic tract. Projects via ventral posteromedial nucleus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the aetiology of phantom limb pain?

A

Cortical reorganisation of somatotopic representation in thalamus/cortex.
Central sensitisation - reduction of inhibitory processes in dorsal horn, sprouting of Aβ fibres into lamina I + II.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name two endocannabinoids.

What do they do?

A

Anandamide.
2-arachidonyl-glycerol.
Inhibits behaviour response to noxious stimuli, limits hyperalgesia and neuropathic pain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do higher brain centres influence pain perception?

A

Descending pathways from periaqueductal grey and reticular formation decrease transmitter release from primary afferent terminals via opioid receptors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the two defining features of pathological pain?

A

Hyperalgesia (increased pain sensation).

Allodynia (touch-evoked pain).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the gate theory of pain?

A

Co activation of mechanoreceptors (Aα/β fibres) with nociceptors with suppress activation of the projection neutron by C fibres.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Name five factors associated with changes in pain perception.

A
Anxiety.
Depressed affect.
Gender.
Circadian variation.
Climatic conditions.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do NSAIDS act?

Side effects? (3)

A

COX inhibition, decrease in prostaglandin.

GI bleeds, renal toxicity, cardiovascular effects.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does paracetamol act?

Side effect?

A

Inhibition of prostaglandin synthesis.

Toxic liver damage.

17
Q

How do opioids work?

Side effects?

A

Activate endogenous analgesic system.

N+V, consitpation, dizziness, somnolence, dry skin.

18
Q

What are the side effects of systemic opioid analgesic use?

Warning sign?

A

Respiratory depression and hypoxia.

Progressive sedation.

19
Q

What are the mechanisms of neuropathic pain?

A

Hyper excitable spinal cord with new dorsal horn inputs.

Remapping of thalamus and cortex.

20
Q

What are features suggestive of neuropathic pain?

A

Different from normal pain.
In absence of tissue damage.
In area of sensory loss.
Allodynia, hyperalgaesia, dysthaesias.

21
Q

How is pain measured?

A

McGill Pain questionnaire.

22
Q

Which types of drugs are used for neuropathic pain?

A
Antidepressants (TCA's, SUIs).
Anticonvulsants.
Opioids.
Membrane stabilising drugs.
Topical drugs.
23
Q

How do tri-cyclic antidepressants work?

Side effects?

A

Inhibition of neuronal reuptake of noradrenaline and serotonin.
Constipation, dry mouth, somnolence, heart abnormalities, insomnia, increased appetite.

24
Q

Which anticonvulsants are used in neuropathic pain?

A

Carbamazepine, phenytoin (NA+ channel blockers - serious + troublesome side effects).
Valproate + clonazepam (GABA agonists).
Gabapentin.

25
Q

How does spinal cord stimulation work?

A

Electrodes stimulate release of endogenous chemicals that dampen down pain.