Pain Lecture Flashcards
Define pain.
Pain is “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage”. - International Association for the Study of Pain
What are the benefits of treating pain?
Physical -
- improved sleep, better appetite
- fewer medical complications (e.g. MI, pneumonia)
Psychological
- reduced sufferring
- less depression
Societal
- lower health costs e.g. shorter hospital stay
- able to contribute to society
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How can you classify pain?
By duration
- Acute
- Chronic
- Acute on chronic
Cause
- Cancer
- Non cancer
Mechanism
- Nociceptive
- Neuropathic
Distinguish acute and chronic pain.
Acute - pain of recent onset and probable limited duration
Chronic - pain lasting more than 3 months; pain lasting after normal healing; often no identifiable cause
What are the differences between cancer and non-cancer pain?
Cancer pain - progressive. may be mixture of chronic and acute
Non-cancer pain - many different causes, acute or chronic
Non-cancer pain - fracture, appendicitis.
What is nociceptive pain? Describe it.
- •Obvious tissue injury or illness
- •Also called physiological or inflammatory pain
- •Protective function
- •Description
- –Sharp ± dull
- –Well localised
Describe neuropathic pain.
- Nervous system damage or abnormality
- Tissue injury may not be obvious
- Does not have protective function
- Description
- Burning, shooting and/or numbness, pins and needles
- Not well localised
Describe acute non-cancer pain. Give examples.
- E.g. fracture, appendicitis
- Symptom of tissue injury or illness
- Usually nociceptive
- Occasionally neuropathic (e.g. scaitica)
Describe chronic non-cancer pain.
- E.g. chronic back pain, arthritis
- Injury may not be obvious
- Complex, may be mixed nociceptive and neuropathic
- Does not respond to usual drug treatment
Descirbe cancer pain and give examples.
- E.g uterine cervical cancer, breast cancer
- Features of acute and chronic pain - may be acute or chronic
- Often mixed nociceptive and neuropathic pain
- Usually gets worse over time if untreated
Define allodynia.
Allodynia refers to central pain sensitization (increased response of neurons) following normally non-painful, often repetitive, stimulation. Allodynia can lead to the triggering of a pain response from stimuli which do not normally provoke pain.
Define hyperpathia.
Hyperpathia is a clinical symptom of certain neurological disorders wherein nociceptive stimuli evoke exaggerated levels of pain. This should not be confused with allodynia, where normally non-painful stimuli evoke pain.
Define hyperalgesia.
Hyperalgesia is a condition where a person develops an increased sensitivity to pain.
Define nociception. How does it differ from pain perception?
How signal get from site of injury to the brain
Vs pain perception - how we “feel” pain
Not the same.
How does nocicpeption lead to pain perception?

What are the 4 main steps in pain phsyiology?
- Periphery
- Spinal cord
- Brain
- Modulation
What are the main peripheral pain receptors?
A-delta C nerve fibres
Describe the physiology of pain in the periphery.
- Tissue injury
- Release of chemicals
- Stimulation of pain receptors (nociceptors)
- Signal travles in A-delta C nerves to spinal cord

Descirbe pain perception in the spinal cord.
- Dorsal horn is the first relay station
- •Aδ or C nerve synapses (connects) with second nerve
- •Second nerve travels up opposite side of spinal cord
How does meditation reduce pain?
Descending inhibition is increased
Describe pain perception in the brain.
- Thalamus is the second relay station
- •Connections to many parts of the brain
- –Cortex
- –Limbic system
- –Brainstem
- •Pain perception occurs in the cortex

How does modulation affect pain perception?
Descending pathway from brain to dorsal horn
Usually DECREASES pain signal
Why is nocebo?
Nocebo - when you tell someone that the treatment will not work. either an effective intervention that should work but doesn’t or other way around.
What is the distribution of neuropathic pain in diabetes?
Glove and stocking distribution

