Pain Management

Question 1

What is the gate theory of pain?

Answer 1

That a non noxious stimuli e.g rubbing will inhibit/decrease ascending pain transmission/pathway

• Non painful stimulus activates pascinian corpuscles of the skin and sensation travels via DCML
• Activates inhibitory interneurones in substantia gelatinosa
• Release inhibitory interneurones e.g encephalins that bind to opioid receptors on pre SN
• Decreases Ca2+ channel opening + increases K+ conductance so AP chance decreases

Question 2

What factors may affect pain perception?
What increases pain threshold?
What decreases pain threshold?

Answer 2

• cultural factors
• pain threshold
• meanings of pain
• sensory input
• previous pain experience

Relaxation, relief, good sleep, sympathy + understanding

insomnia, anxiety, mood, fear, discomfort

Question 3

How do we define pain ( 6 concepts)?

Answer 3

• biopsychosocial impact of pain
• protective but adverse effects
• verbal communication not only way of expressing pain
• emotional + sensory experience
• experiences affect pain concept/perception

Question 4

Compare acute vs chronic pain

Answer 4

Acute: < 3 months, normally protective
Chronic: > 3 months, not useful with adverse effects

Question 5

What are the 5 main types of chronic pain?

Answer 5

Myofascial 
Musculoskeletal
Fibromyalgia 
Neuropathic
chronic headaches

Question 6

What is neuropathic pain?

Answer 6

Pain caused by a disease or lesion of the somatosensory nervous system
lesion = known damage
disease = cause of damage is known e.g stroke, diabetes
It is anything that damages the nerves

Question 7

What is nociceptive pain?

Answer 7

Pain in response to actual or potential tissue damage

Noxious stimuli -> electrical impulse which is relayed through the spinal cord

Question 8

What is nociplastic pain?

Answer 8

Occurs due to altered nociceptive responses despite no evidence of actual/potential tissue damage or disease/lesion or somatosensory NS

Patient can be said to have more sensitive nerves

Question 9

What is central pain?

Answer 9

Rare syndrome affecting the central nervous system
Includes strokes ( flaccid weakness -> UMN signs)

Question 10

What is sensitisation?

What are the 2 main types?

Answer 10

Reduced threshold/ increased responsiveness of nociceptors to their normal input

Central
Peripheral

Question 11

What maladaptive changes occur due to sensitisation?

Answer 11

• Decreased descending inhibition
• Glial cell activation ( transmission + storage of pain signals)
• Chains in NT i.e increased glutamate, increased Ca2+ channels

Question 12

What is the wind up phenomenon?

Answer 12

Exaggerated response to normal stimuli e.g touch/pressure

Question 13

What is the MOA gabapentin?

How is it used to treat sensitisation?

Answer 13

Binds to alpha subunits og Ca2+ channels

Prevents Ca2+ influx and hence up regulation that occurs in sensitisation

Question 14

What is allodynia?
What is hyperalgesia?
What is hypoalgesia?
What is hyperpathia?

Answer 14

Pain caused by a non painful stimulus ( lower threshold)
Increased pain from a painful stimulus ( increased response)
Low pain from a painful stimulus ( high threshold, low response)
Pain rxn to repetitie stimulus ( low threshold, high response)