Physiology and Pathophysiology or Pain

Question 1

What is pain?

Answer 1

An unpleasant sensory and emotional experience which we primarily associate with tissue damage or describe in terms of such damage or both

Question 2

What is nociception?

Answer 2

The detection of tissue damage by specialised transducers connected to A-delta and C-fibres

Question 3

What are the basic steps in the pathway of pain?

Answer 3

Periphery, Spinal cord, Brain, Modulation

Question 4

What are nociceptors?

Answer 4

Free nerve endings of A-delta and C-fibres that respond to thermal, chemical, mechanical noxious stimuli

Question 5

Where are primary afferents located and synapse?

Answer 5

Cell body in dorsal root ganglion

Synapse at spinal cord

Question 6

What is the difference between A and C fibres?

Answer 6

A fibres conduct sharp pain

C fibres conduct dull pain

Question 7

What type of tract in the spinal dorsal horn takes charge of pain?

Answer 7

Lateral spinothalamic tract

Question 8

Where does the spinothalamic tract arise?

Answer 8

Rexed lamina 2 and 5

Question 9

Where does pain perception occur in the brain?

Answer 9

Somatosensory cortex

Question 10

What change occurs in the nociceptor with allodynia?

Answer 10

Decreased threshold for response

Question 11

What change occurs in the nociceptor with hyperalgesia?

Answer 11

Exaggerated response to normal and supernormal stimuli

Question 12

What change occurs in the nociceptor with spontaneous pain?

Answer 12

Spontaneous activity in nerve fibres

Question 13

What is central sensitisation?

Answer 13

Response of second order neurons in the CNS to normal input both noxious and non-noxious

Question 14

What are the 3 components of central sensitisation?

Answer 14

Wind-up
Classical
Long-term potentiation

Question 15

What are the key points of wind up in central sensitisation?

Answer 15

Only involves activated synapses
Homosynaptic activity dependent progressive in response to neurons
Manifests over courses of stimuli an terminates with stimuli

Question 16

What are the key points of classical in central sensitisation?

Answer 16

Involves opening new synapses
Heterosynaptic activity dependent plasticity
Immediate onset
Outlast the initial stimuli duration

Question 17

What are the key points of long term potentiation in central sensitisation?

Answer 17

Involves mainly activated synapses

Occurs primarily for very intense stimuli

Question 18

What are the differences between acute and chronic pain?

Answer 18

Acute: presence of noxious stimuli, usually nociceptive
Chronic: Noxious stimuli not essential, nociceptive, neuropathic or mixed

Question 19

What is neuropathic pain?

Answer 19

Pain initiated or caused by a primary lesion or dysfunction in the tomato-sensory nervous system

Question 20

What can be used to treat neuropathic pain?

Answer 20

Anti-depressants and anticonvulsants

Question 21

What are the treatment options for pain associated with transduction?

Answer 21

NSAIDs
Ice
Rest
LA blocks

Question 22

What are the treatment options or pain associated with transmission?

Answer 22

Nerve blocks 
Opioids 
Anticonvulsants 
Cordotomy 
DREZ

Question 23

What are the treatment options for pain associated with perception?

Answer 23

Education 
Cognitive behavioural therapy 
Distraction 
Relaxation 
Graded motor imagery 
Mirror box therapy

Question 24

What are the treatment options for pain associated with descending modulation?

Answer 24

Placebos
Opioids
Antidepressants
Spinal cord stimulation