Lecture 18: Chronic Pain

Question 1

Define chronic pain

Answer 1

i. outlasts healing time (3-6 months)

ii. not due to residual injury/inflammation

Question 2

List some preisping factors to chronic pain.

Answer 2

• women
• early life stress/injury
• stress
• psychological/personality factors
• depression/anxiety (bidirectional)

Question 3

List 4 ways chronic pain occurs through neuroplasticity

Answer 3

1. peripheral changes in pain receptors (more of them)
2. pain neurons grow and increase connections (increased activation)
3. glial cells in spinal cord remodel (intensify pain transmission)
4. CNS changes (central sensitisation)

Question 4

What is the relationship between pain and depression?

Answer 4

High comorbidity. Depressive symptoms predict future chronic pain, vice versa

Question 5

What evidence exists about relationship between meditation and pain? (4)

Answer 5

i. reduced pain related activation in SSC and insula
ii. increased activation in aCC (opposite effect)
iii. reduced amygdala activation
iv. pain relief not due to associated endorphin release

Question 6

What mechanisms involve pain and sleep?

Answer 6

1. descending pain inhibitory pathway
2. increased inflammatory cytokines
3. reduce inhibition from distraction
4. central sensitisation modified

Question 7

What is affected by fibromyalgia?

Answer 7

• central processing of pain - lower threshold, greater activation
• ascending pathways - increased CSF substance P
• possible descending pathways too - increased CSF serotonin/norepinedrine, reduced ACC
• sleep - light and restless; poor sleep worsens symptoms