Pain Flashcards
define dysesthesia
unpleasant and abnormal sensation
can be evoked or spontaneous
what are the 2 types of dyesthesia?
- allodynia
- hyperalgesia
what is allodynia?
pain evoked by stimulus that is not usually noxious
(a cotton ball evoking pain)
what is hyperalgesia?
excessive sensitivity to stimuli that are normally mildly painful
T/F: when a part of the body is injured, special pain receptors convey the pain message to your brain
FALSE
incomplete concept
pain is a perception/experience
nociceptive fibers carry sensations that can be later interrpreted as pain
what evidence is there that type C and A-delta fibers do not carry pain signals?
if they carried pain fibers then every time they were stimulated, the result should be the same pain.
Not the case, the same injury in the same person can cause different levels of pain depending on the context
T/F: pain only occurs when you are injured
FALSE
injury or degeneration may be present in the absence of pain
significant pain may be present with no identifiable disease process or even after tissue healing
pain is an emotional experience and can develop due to emotional overload. However it is important to not classify it as _____________
a psychosomatic issue
T/F: the timing and intensity of pain matches the timing and number of signals in nociceptors
FALSE
repeated signals from nociceptors to the dorsal horn of spinal cord can result in action potential windup leading to heightened sensitization
what is action potential windup?
repeated stimulation of nociceptors to the dorsal horn of the spinal cord resulting in a progressive increase in action potentials
what can action potential windup cause?
heightened sensitization
death of interneuron in dorsal horn ⇒ decreased ability to modulate response
2nd order neuron receptors get replaced with receptors that increase danger messages to the brain
T/F: Nerves have to connect a body part to your brain in pain
FALSE
phantom limb pain
T/F: in chronic pain , the CNS becomes more sensitive to nociception
TRUE
due to:
- action potential windup
- changes at the interneuron ⇒ increased sensitization
- changes in descending modulation of pain
how does changes at the dorsal horn interneurons come about? How does this result in increased sensitization?
persistent input from C-fibers → changes interneuron
→ changes in 2nd order neuron receptors → sprouting and expansion of receptor fields → increased sensitization
T/F: the body tells the brain when it is in pain?
FALSE
the brain tells the body
T/F: the brain sends messages down your spinal cord that can increase the nociception going up your spinal cord?
TRUE
changes in the CNS as a result of AP windup allow for increased info to be processed in the brain
T/F: nerves adapt by increasing their resting level of excitment
TRUE
ion channels possess neuroplastic characteristics
how often does ion expression change on a nerve?
continuously
half-life reported to be 48 hours
T/F: Chronic pain mean that an injury hasn’t healed properly
FALSE
injury and pain are not synonymous
not uncommon for a chronic pain pt to have no injury history
T/F: receptors on nerves work by opening ion channels in the walls of the nerve
TRUE
ion channel expression constantly changes
ion channels are found on axons
what is ion channel expression dependent on?
genetic coding
and
the brain’s expression of the survival needs of the individual
how is increased expression of certain ion channels impactful to chronic pain?
increased expression of certain ion channels may result in the development of sensitivity to the stimulus that opens that specific channel
T/F: the brain decides when you will experience pain
TRUE
pain is a brain construct based on perception of threat
T/F: worse injuries always result in worse pain
FALSE
stepping on a lego vs soldier not noticing getting shot
T/F: when you are injured, the environment that you are in will not have an effect on the amount of pain you experience
FALSE
injuries in high stress environments are 7-8x more likely to result in persistent pain
T/F: it is possible to have pain and not know about it
FALSE
the decision to produce pain is a conscious decision by the brain
this is why you aren’t in pain while under anesthesia
T/F: Nerves can adapt by making more ion channels
TRUE
T/F: 2nd order nociceptor post-synaptic membrane potential is dependent on descending modulation
TRUE
how should the placebo effect be viewed?
an endogenous mechanism to modulate the pain experience
T/F: Nerves adapt by making ion channels stay open longer
TRUE
G-protein channels can remain open for minutes
in persistent pain, a greater concentration of G-protein channels may be seen in 2nd order neurons
can contribute to the windup effect
T/F: when you are injured, chemicals in your tissues can make nerves more sensitive
TRUE
various chemicals can influence opening/closing of specific ion channels
Adrenaline and cortisol
T/F: in chronic pain, chemicals associated with stress can directly activate nociception pathways
TRUE
the stress response
using a the lion metaphor, describe the stress response if “the lion enters the room and follows you around for months/years”
if the stressors remain present for months, the stress response of increased adrenaline is then followed by cortisol changes in your body
what is the IASP definition of pain?
pain is an unpleasant sensory and emotional experience which follows actual or potential tissue damage or is described in terms of such damage
List 2 key things to keep in mind when defining what chronic pain is
- it can be thought of as maladaptive neuroplasticity (increased sensitivity)
- associated with abnormal intracortical inhibitory mechanisms
- smudging
List the PNE Principles (summary)
- pain is an output of the brain
- pain is not always an indicator of tissue damage
- the amount of pain you percieve does not = the amount of damage
- in chronic pain, the brain believes you are in danger and need protecting
- context of pain experience is vital
what is fibromyalgia?
chronic disorder
widespread pain, abnormal pain processing (pain amplification and impaired descending inhibition), sleep disturbances and fatigue
what is chronic regional pain syndrome (CRPS)?
syndrome resulting in pain, vascular changes and atrophy
occurs in a regional distribution as opposed to a peripheral nerve or nerve root distribution
S/S worse in distal extremities
when does CRPS usually occur?
secondary to trauma (surgery, fracture, crush injury, sprain)
what is the primary complaint for CRPS?
severe, spontaneous pain, out of proportion to the injury
what are the S/S of CRPS?
- sensitivity to cold, pressure and touch
- early symptoms:
- red/pale skin
- excessive sweating
- edema
- skin atrophy
- later signs
- skin becomes dry and cold and joints become stiff and swollen
- motor signs (paresis, spasms, and tremor)
what is the primary precipitating factor for CRPS?
disuse
