Mechanisms of Pain Flashcards
(42 cards)
According to the International Association for the Study of Pain what is pain?
“An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”
3 treatment goals in regards to pain
1) Resolve underlying pathology
2) Modify patient’s perception of discomfort
3) Maximize function whether or not the source of pain can be modified
Pain is categorized by _____ or ____.
Duration
Source
Two types of pain categorized by duration
1) Acute
2) Chronic
Two types of pain categorized by source
1) Referred
2) Radiating
Acute vs. Chronic Pain
Acute pain lasts less than 6 months whereas chronic pain persists past the normal time for tissue healing (>6 months)
The major difference between chronic and acute pain is what??
Acute pain is a reaction to a noxious stimulus and will last as long as this stimulus exists.
Chronic pain persists after the noxious stimuli is gone
Referred vs. Radiating Pain
Referred pain is experienced in an area other than the location of the actual tissue damage, whereas radiating pain is caused by irritation of nerves and nerve roots
When treating referred pain what is important to keep in mind?
Always treat the joint above and below
Are there common referral patterns from internal organs?
Yes, there are common sites of referred pain for specific internal organs
5 red flags for referred pain
1) Pain that is not relieved by rest
2) Pain that is not relieved by change of position
3) Pain/symptoms that do not fit an expected mechanical or neuromuscular pattern
4) Pain that increases at night
5) When pain cannot be reproduced, aggravated, or altered in any way
Pain is a response to stimulation of _____ _____.structures.
peripheral nociceptive
Afferent vs. Effernet nerve fibers
- Afferent nerve fibers transmit impulses from the sensory receptors toward the brain
- Efferent nerve fibers such as motor neurons transmit impulses from the brain toward the periphery
What are nociceptors?
free, non-corpuscular peripheral nerve endings
2 types of nociceptors
1) C fibers (aka Group IV afferents)
2) A-delta fibers (aka Group III afferents)
Describe C fibers
- Small, slow, unmyelinated (1 – 2.5 meters/second)
- Transmit pain sensations that are often described as dull, throbbing, aching, burning, tingling or tapping
- Slow onset, long lasting
- Accompanied by nausea, sweating, incr. BP or HR
- Can be blocked by opioids (morphine, oxycodone, hydrocodone)
Describe A-delta fibers
- Small, faster, myelinated (30 meters/second)
- Most sensitive to high intensity mechanical stimulation
- Described as sharp, stabbing, or picking
- Quick onset, last a short time
- Generally not blocked by opioids
Pain-transmitting neurons originating in the spinal cord ascend to the thalamus via what tracts?
spinothalamic (ST) tracts
In the hypothalamus what tracts relay sharp pain?
Lateral spinothalamic tract (LST)
In the hypothalamus what tracts relay prolonged, aching pain?
Anterospinothalamic tract (AST)
What type of cell increases muscle spasms?
T-cells
How does the Sympathetic Nervous System influence pain?
- SNS involved in producing effects that prepare the body for “fight or flight”
- These hyperactive responses from the SNS can increase the severity of pain and cause symptoms of sympathetic activity
What is Complex Regional Pain Syndrome (CRPS)?
an abnormal sympathetic activation caused by a hyperactive response of the sympathetic nervous system to an acute injury, or a failure of the sympathetic response to subside after an acute injury, which can increase pain severity and exaggerate s/s of sympathetic activity
3 Pain Theories
- Specificity Theory
- Pattern Theory
- Gate Control
