B7-005 Pain 2 Flashcards
acute pain goes through the […] system
spinothalamic
carried by unmyelinated C fibers
dull, burning pain-poorly localized
slow pain
carried by A-delta thinly myelinated fibers
sharp pricking pain
accurately localized
fast pain
slow pain is carried in the […] tract
paleothalamic
has several “waypoints” on way to thalamus, envokes “memories” of pain
fast pain is carried in the […] tract
neothalamic
goes straight to thalamus
why does slow pain invoke an emotional response?
it is diffusely projected throughout the cortex
why does pain persist after the noxious stimuli is removed?
peripheral :sensitization by chemical mediators (they depolarize the receptor and make it more sensitive to subsequent stimuli)
central: decreased pain receptor thresholds and changes in synaptic central circuits over time
similar to slow pain, affecting the internal organs
visceral pain
why is visceral pain hard to localized?
very high percentage of C fibers going through paleothalamic tract which projects diffusely
has characteristics of slow pain
is commonly referred to overlying somatic structures
visceral pain
describe the mechanism of referred pain
convergence of cutaneous and visceral nociceptors onto same dorsal horn
OR
branching pattern of sensory nerve
secondary to disruption of normal pain physiology caused by abnormal sensitization, conduction, modulation, or perception
chronic (abnormal) pain
mildly painful stimuli perceived as more painful that it is
hyperalgesia
nonpainful stimuli perceived as pain
allodynia
painful tingling (like foot asleep)
dysesthesia
persistant hyperpathia associate with vasomotor changes after an injury
usually after a period of immobilization, affected limb may have color changes
Complex Regional Pain Disorder
AKA reflex sympathetic dystrophy, causalgia (with nerve injury)
focal area of demyelination with cross talk between bare axons
neuralgia
treatment of trigeminal neuralgia
carbamezapine
surgery
treatment of Complex Regional Pain Disorder [3]
aggressive mobilization
pain control
sympathetic blockade
damage to somatosensory systems, associated with numbness
presumed secondary to decreased modulation
defferentation pain
describe the gate control theory of pain
modulation of pain wants the non-painful and painful stimuil to be balanced
a decrease in either one would cause an increase in the other and vice versa
loss of non-painful sensory inputs causes a relative pain increase, pain is perceived
defferentation pain
inhibitory pain pathway
triggered by fight or flight
central pain modulation
describe the central pain modulation pathway
periaqueductral gray –> opiate receptors –> rostroventral medulla –> NE 5HT –> dorsal horn –> enkephalin interneurons
treatment used to decrease sensitization [4]
early mobility
capsacin
NSAIDs
steroids
treatment used to decrease pain conduction [3]
nerve block
spinothalamic tractotomy (used for cancer with poor prognosis)
stabilize nerves with anti-epilepsy drugs
treatments used to increase pain modulation [2]
increase non-painful input: mechanical stimulation, trans-cutaneous stimulator, posterior column stimulator, stimulate periaqueductal gray
medication: antidepressants, opiates
treatments used to change pain perception
behavior/relaxation therapy
biofeedback
treatment for anxiety/depression
recurrent brief episodes of pain in the CN V distribution
trigeminal neuralgia
most cases of trigeminal neuralgia are caused by
vascular compression of the CN V root
electric “shock” like pain over the jaw triggered by talking, chewing, or touch
trigeminal neuralgia
treatment for trigeminal neuralgia
carbamazepine (epilepsy drug)
**if no response, they need surgical intervention
“burning” pain and allodynia following herpesvirus infection
postherpetic neuralgia
describe the pathophysiology of postherpetic neuralgia
decreased modulation from defferentation
used to reduce the risk of postherpetic neuralgia
antivirals
**diagnosis must be caught early to have better prognosis
damage to descending pain inhibitory pathways can cause
decreased modulation
treatment of postherpetic neuralgia
amitriptyline
acute migraine treatment
triptans (diptans if risk of stroke)
antiemetics
prophylactic migraine treatment
beta blocker
amitriptyline
valproate, topiramate (anti-epileptics)
botulinum toxin
anti-CGRP monoclonal antibodies
NSAIDs
treatment of deafferentation syndrome
tricyclic antidepressant
blocks sodium channels in the nerve
lidocaine
[…] syndrome following a thalamic stroke is common
deafferentation pain
allodynia with swelling, redness of skin, and skin changes
complex regional pain syndrome/reflex sympathetic dystrophy
the projection of pain impulses to the cerebral cortex is […]
diffuse
extends beyond somatosensory complex
physiologic basis of referred pain
convergence of primary sensory neurons from the skin and affected organ on the same populations of secondary sensory neurons within the spinal cord
