Pain Flashcards
What can pain cause?
Withdrawal reflex it muscle guarding
What is pain?
An unpleasant experience involving the interaction of physical and psychological responses due to actual or potential tissue damage
What are the pain categories?
Fast vs slow
Acute vs chronic
Projected vs referred pain
What factors are involve in pain?
Anatomical structures, physiological reactions, psychological, social, cultural and cognitive factors
What is acute pain?
<6 months
What is persistent pain?
More treatable then chronic pain
What is chronic pain?
> 6 months
What does referred pain involve?
Trigger points
What is radiating pain?
Similar to referred-travels along a nerve
What is somatic pain?
Sclerotomic. (Deep)
Pain sources
Cutaneous, deep somatic, visceral, pathogenic
Cutaneous pain
Sharp, bright and burning with fast and slow onset
Deep somatic pain
Originates in tendons, muscles, joints, periosteum, and blood vessels
Visceral pain
Begins in organs and is diffused at first and may become localized
Psychogenic pain
Felt by the individual but is emotional rather than physical
Fast pain
Localized and carried through a delta axons
Slow pain
Aching, throbbing, or burning and transmitted thru C fibers
What can help indicate severity or injury/condition?
intensity and location
What can chronic pain lead to?
physical, psychological, and social dysfunction
What are the characteristics of an individual with chronic pain?
prolonged physical inactivity, muscle weakness, decreased endurance, dramatize complaints, recieve excessive treatment, drug misuse, depression, difficulty sleeping, changed eating behaviors, social isolation, dependence on other
What are four potential causes for chronic pain?
- changes in sympathetic nervous system
- changes in adrenal activity
- reduced production of endogenous opioids
- sensitization of primary afferent and spinal cord neurons
central hypersensitization
the pathways transmitting pain continue to discharge after stimulation has ceased
What four structures are most sensitive to damaging (noxious) stimuli?
- periosteum (joint capsule)
- subchondral bone, tendon, ligaments
- muscle, critical bone
- synovium, articular cartilage
A-alpha fibers
sensitive to pressure and can produce parasthesia
What are three types of referred pain?
myofascial, slerotomic, and dermatomic
How is sclerotomic pain transmitted?
Thru C fibers which can result in autonomic changes (BP, sweating) and depression, anxiety, anger, or fear
How is dermatomic pain transmitted?
A-delta fibers thru the thalamus and cortex
What are nociceptors?
Specific nerve endings respond to all painful stimuli by sensing pain
How does pain travel?
Thru small myelinated A-delta fibers and unmyeliated C fibers then transmit this pain sensation to the spinal cord
Where are all nociceptors?
In all tissue except the nucleus pulposus nad the inner component of the annulus fibrosus of spinal discs
How do nociceptors work?
They release neuropeptides and then convert the stimulus into electrical activity thru transduction creating action potentials
What kind of pain does group IV afferent C fibers cause?
dull, aching, burning, throbbing, tingling, tapping pain sensations
Can opiates block activation of C fibers?
yes
Can opiates block activation of A-delta fibers?
no
What kind of pain does group III afferents A-delta fibers cause?
sharp, stabbing, ricking pain sensation
What do A-delta fibers respond to?
high intensity mechanical stimulation or heat/cold stimulation
What’s the difference between C fibers and A-delta fibers?
A-delta fibers may transmit non-noxious stimuli
What are T cells?
second order neurons that connect with interneurons, efferent neurons for spinal cord reflexes, or to afferent neurons which transmit to the cortex
What inhibits second order neurons?
substantia gelatinosa (A-beta nerves)
What modulates the flow of afferent pathways?
norepinephrine, serotonin, enkephalins
How do second order neurons work?
They transmit pain stimuli thru lateral spinothalamic tract(sharp pain and pain localization) and the anterospinalthalamic tract (aching pain and emotions) contralateral aspect of the spinal cord to the thalamus
What do third order neurons do?
They interact with the second order afferents to send pain to the cortex where sensation of pain reaches consciousness
Where does the “fight or flight” response come from?
The sympathetic nervous system
What are sympathetic efferents activated by?
acute pain/injury but they do not cause pain
How does surgery or chemical means help with pain?
They interrupt with sympathetic nervous system actvity
Reflex sympathetic dystrophy (RSD)
post traumatic dystrophy, sympathetically maintained pain, complex regional pain syndrome, tissue damage with or without nerve involvement
What can reflex smpathetic dystrophy cause?
severe pain, hyperesthesia, skin atrophy, edema, stiffness, increased sweating, decreased hair growth
What is substance P?
chemical mediator supposedly involved with transmission of neuropathic and inflammatory pain
Where is substance P found?
central nervous system. 20% of C fibers, and inflammatory exudate
What does substance P do?
excite pain transmitting neurons in the dorsal horn
What do opiopeptins do?
Bind to opiate receptors in the nervous system and acts like morphine
Where are opiopeptins found?
in peripheral nerve endings, regions of the nervous system and brain
What are some pain assessment scales?
visual analog, graphic pain charts, McGill pain questionnaire, numeric pain scale, and facial scale
How do opioids and opiopeptins inhibit pain
Cause presynaptic inhibition as they supress the inward flux of calcium, cause postsnaptic inhibition as they activate an outward potassium current, inhibit gamma aminobutyric acid from being released in periaqueductal gray matter and the raphe nucleus, and electrical stimulation of the above areas has been shown to inhibit pain
What do physical agents do to control pain?
control the release of inflammatory mediators, stimulate afferent non-noxious sensory fibers, slow nerve conduction velocity, and decrease sensitivity of muscle spindle
What is mechanical trauma?
It invokes both C and A-delta fiber sensations
When does a muscle spasm occur?
when T cells synapse with anterior horn cells in a spinal cord reflex loop causing muscle contractions
What happens in the pain-spasm-pain cycle?
Fluid build up of irritants, muscle contraction mechanically compressing nociceptors
What are some benefits to using physical agents?
reduced side effects, patient can use independently to treat themselves, and they provide comfort when nothing else is available
messiner’s corpuscles
activated by light touch
pacinian corpuscles
respond to deep pressure
merkel’s corpuscles
respond to deep pressure and hair follicle deflection
ruffini corpuscles
sensitive to touch, tension, heat, joint change in position
krause’s end bulb
sensitive to decreased temperature
nociceptors
sensitive to extreme mechanical, thermal, or chemical energy
