Reading 5 - Pain

Question 1

What is pain?

Answer 1

o Nociception = detection of a noxious stimuli
o Pain = The discomfort arising as a result of nociception (perceptual experience arising in the brain)
o Can be key for survival but also debilitating

Question 2

What is pain triggered by

Answer 2

 Receptors at the ends of nociceptive sensory neurons (FNE) in the skin, muscles, organs, joints and more detect a change in temperature, vibration, pressure etc of a given magnitude which causes AP firing and propagation of an electrical signal to the spinal cord and brain which is associated with pain

Question 3

Pain Network

Answer 3

 Multitude of brain areas coordinated with electrical activity during the pain experience
 Emotional pain and phsycial pain shows activity in
* Insula
* Thalamus
* Anterior cingulate cortex

Question 4

CIPS

Answer 4

o CIPS (Congenital Insensitivity to Pain)
 Effects 1 in 1 million people
 Cannot feel pain under any circumstances
 Tend not to have a long-life expectancy
 Caused by a mutation in the gene SCN9A which codes sodium channels in nociceptors
* The mutation stops these sodium channels being expressed so pain signals cannot form and therefore reach the brain

Question 5

Chronic Pain

Answer 5

o Chronic Pain = pain extending longer than 3 months
 Affects more than 30% of the population
 Is a problem with the brain as an unjury that leads to pain is persisting after the tissue has recovered as the brian has rewired itself and learnt to send the pain signal despite there being no reason
* This is central sensitisation
* Treatments
o Pain reprocessing theory which involves shifting people’s beliefs about the causes and threat of pain
o Haider Warraich believes chronic pain is driven by emotion and memory so treating this is key to resolving it

Question 6

Modulators of Pain

Answer 6

o Emotion;
o State of Mind;
Distraction
Mindset
o Drugs
Paracetamol can number physical pain and social rejection
Opioids mimic the natural downstream pain inhibition mechanisms

Question 7

Ways to Measure Pain

Answer 7

1. Qualititative; Highly subjective
2. Qualitative pain threshold measures; Apply a neutral stimulus until it becomes uncomfortable (doesn’t inform however on current pain)
3. McGill Pain Questionaire 1975 – asks people to note their pain with 78 different descriptors which can be coded to intensity. Is also used with localisation of pain and an intensity question
4. Objective measures; biological signals like pulse rates, sleep patterns and brain activity
5. Artificial intelligence; can analyse different pain metrics. Studys show there are 7 types of useful data that can be recorded on a smartwatch and are a combination of self-reports on modd, alertness, sleep, movility etc to assess individuals pain and predict how It will evolve. A Study that assessed efficacy of this took 76 people using TEMs to manage lower back pain and AI gave daily recommendations. At the end 84% reported significant improvements in their pain

Question 8

Pharmacological Interventions for Pain and their Efficacy

Answer 8

o Paracetamol (acetaminophen) has little to no effect on extreme pain and can be toxic to the liver
o Ibuprofen, a non-steroidal anti-inflammatory can produce headaches and indigestion
o Opioids, mimic the bodies natural painkilling mechanisms and is highly effective for acute and chronic pain. They are however associated with addiction and overdose

Question 9

Genetics as a Pain Treatment

Answer 9

o SCN9A (Geoff Woods research). – SCN9A is a gene that if blocked, would prevent pain signalling by preventing NAV1.7, a sodium channel, from being expressed which is found exclusively in sensory neurons and therefore could stop pain signalling. People who naturally don’t have SCN9A feel no pain, however, inhibiting the NAV1.7 in wildtype individuals has failed to mitigate pain

Question 10

Bacterial Toxins for Pain Management

Answer 10

o Bacterial Toxins; Isaac Chiu found that bacteria can directly activate the sensory neurons that signal pain and silence them. Toxins from Bacillus Anthacis (associated with anthrax) can silence sensory neurons temporarily

Question 11

o Psychological treatments – best for chronic and emotional pain (examples and Evidence)

Answer 11

 People who underwent breast cancer surgery who were given techniques to self-regulate pain (my surgical success) used opioids for 5 days less than controls
 Pain reprocessing therapy (PRT) teaches people to reframe pain as non-threatening. 66% of people in a study who received PRT were pain free or nearly pain free compared to 20% with a placebo and 10% from std treatment
 Empower Relief (Darnall) is a 2 hour session that educates pain management. One session appeared to be as effective as eight 2 hour CBT sessions

Question 12

How much have Opioid deaths increased in the US

Answer 12

Opioid deaths increased by one third between 2020 and 2021

Question 13

Genetic link to chemesthesis detection

Answer 13

Temperature and Spice pain relies on the TRPv1 gene and therefore TRPv1 protein found in nociceptors which is found in some nociceptors and respond to heat as well as capscaicin

Question 14

What is the most common Pain condition?

Answer 14

Chronic Pain

Question 15

TRPV1

Answer 15

o TRPV1 is the gene that codes for the TRPV1 protein, in free nerve endings to code for spice responding to capsaicin (blocking this channel could be a modulator for pain)

Question 16

Pain as a Qualia

Answer 16

o Pain isn’t always a reflection of the pain we experience as there is an affective/emotional system in the brian for pain which is more complex and less well understood

Question 17

Suicidal Ideation and Pain

Answer 17

o Up to 20% of people with chronic pain conditions have suicidal thoughts and 5 – 14% follow through with this

Question 18

Pain and Inequality

Answer 18

o Pain Gender Gap;
 Women are less likely to be accommodated for their pain and have a higher pain sensitivity
 This is reflected in longer hospital weight times, more misdiagnoses of heart attacks and lower likelihood of receiving pain treatment
o Depression and anxiety can worsen a person’s experience of pain, dull the efficacy of opioids and heighten the risk of chronic pain
o Placebo Power; Nocebo (=when negative beliefs worsen pain) and placebo (a treatment with no medical effect improves pain). Studies show both deceitful and open placebos (where the participant knows it’s a placebo) work.

Question 19

o Brandl et al., study of chronic pain

Answer 19

 Did a meta-analysis on 320 brain scans of people with chronic pain, anxiety and depression
 Similar brain changes are seen between groups, including a decrease in brain volume, connectivity to the frontal cortex and insula
 Psychotherapy and antidepressants can treat all three

Question 20

o Choong-Wan Woo 2015

Answer 20

 Applied heat to an arm to measure threshold aka the neurological pain signature
 Then asked participants to imagine the pain as blistering or a warm blanket
 Whilst the pain signature remained the same, qualitative perception of pain changed

Question 21

Case study of Clare

Answer 21

 Had debilitating pain ; nociplastic plan
 Diagnosed with chronic primary musculoskeletal pain
Committed suicide after failing to mitigate pain symptoms

Question 22

types of Pain

Answer 22

o Nociceptive pain = pain driven by injury or inflammation

o Neuropathic pain = pain by damage to sensory nerves

o Nociplastic pain = body enters central sensitisation where rather than protecting tissue damage, pain centre becomes hypervigilant and responds disproportionately to minor injuries or inflammation converting them into excruciating pain. Includes fibromyalgia and chronic primary musculoskeletal pain
Can be driven by bottom-up pain, where normal pain becomes out of proportion
Or top down factors where there is no obvious trigger for its onset
Tends to be treated non-pharmacologically

Question 23

Nociplastic Pain

Answer 23

Nociplastic pain = body enters central sensitisation where rather than protecting tissue damage, pain centre becomes hypervigilant and responds disproportionately to minor injuries or inflammation converting them into excruciating pain. Includes fibromyalgia and chronic primary musculoskeletal pain
Can be driven by bottom-up pain, where normal pain becomes out of proportion
Or top down factors where there is no obvious trigger for its onset
Tends to be treated non-pharmacologically