Clinical Management of Pain--Blake Flashcards
What is the IASP definition of pain?
An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage
What are 4 of the main effects of chronic pain on a patient? What does each mean?
Physical functioning–activity level, sleep
Psychological morbidity–depression, anxiety, anger
Social Consequences–relationships, sex
Societal Consequences–health care costs, lost work days.
What are the 4 categories of pain when it is categorized in an etiology-based manner?
Nociceptive
Neuropathic
Cancer
Psychogenic
What are the 2 main types of nociceptive pain & what does each refer to?
Somatic Pain–arises from bone, muscle, ligament, skin
Visceral Pain–arises from organs
What is neuropathic pain?
pain arising from a lesion or disease affecting the somatosensory system.
What is mixed pain?
combo of nociceptive & neuropathic, usu seen in cancer
What type of pain are these examples of?
cholecystitis
nephrolithiasis
visceral pain (nociceptive pain)
What type of pain is this an example of?
chest wall pain from lung cancer
mixed pain
What type of pain are these examples of?
radiculopathy, CRPS
neuropathic pain
What type of pain are these examples of?
ankle sprain
arthritis
somatic pain (nociceptive pain)
Why is it that a person w/ 9/10 chronic pain can roll over & go to bed?
b/c chronic pain just operates differently than acute pain. need to think of the 9/10 as the amount that the pain is taking over their lives.
What are the 4 pain assessment scales used?
Verbal Pain Intensity Scale
Visual Analog Scale
0-10 Numeric Pain Intensity Scale
Faces Scale
What is the estimate for the total number of people in the U.S. experiencing neuropathic pain (excluding back pain)?
1, 765, 000.
What are the 3 components of a comprehensive treatment plan?
biological approach
psychological intervention
social/rehabilitative issues
What are the 2 main sympathetic blockade techniques?
stellate ganglion block
lumbar sympathetic block
What is the usu nociceptor structure & what are the 2 main types?
unmyelinated axons w/ small cell body diameter
2 types: C-fiber & A delta fiber
What are the 2 functional properties of nociceptors?
- encode stimulus intensity into a noxious range
2. primary afferent sensitization: increase in excitability due to endogenous mediators & factors
What are the 4 events that are necessary for the nociceptor to convey info to the CNS about noxious stimuli?
- Signal Transduction
- Signal Transformation
- AP propagation
- Signal Transmission
What happens during signal transmission?
AP initiates release of NT on the 2nd order neuron
Which receptor is important in nociceptor signal transduction & depolarization of the peripheral terminal?
TRPV1 receptor
Describe the characteristics of peripheral nociceptor sensitization.
increased excitability lower threshold for activation sometimes ongoing spontaneous activity main cause of hyperalgesia can cause central sensitization
What does it mean to have an increase in excitability of peripheral nociceptors?
increase in excitability = increased response to noxious stimuli
What is hyperalgesia?
increased pain produced by the stimulation of the site of injury
What is central sensitization?
an increased excitability of central neurons
What is allodynia?
pain resulting from normally painless stimuli
What are lamina I & lamina II the primary site for?
excitatory neuropeptide input from primary afferent neurons
What is lamina II considered?
substantia gelatinosa
Spinomesencephalic neurons target which 2 areas?
midbrain
PAG: periaqueductal grey
What is the periaqueductal grey an important region for?
important area for regulation of nociception
key structure for relaying descending pain modulation via RVM nuclei
What are 4 super important areas for supra spinal pain processing?
periaqueductal grey
thalamus
sensory cortex
limbic system
What happens @ the thalamus?
almost all sensory systems send signals to the thalamus that are then directed to specific cortical representation areas
What is the rough idea behind the Gate Control theory of pain?
activation of a beta fibers produces an inhibitory effect on a delta & c fibers. Rubbing an area of injury can help get rid of the pain–>stops the pain signals.
After an injury, what happens to a fiber terminals & c fiber terminals?
c fiber terminals atrophy
a fiber terminals sprout into the superficial dorsal horn
What are the 2 main EAA (excitatory amino acids) that are NTs released from primary afferents & act on ligand-activated ion channels?
glutamate
aspartate
What are the 2 main EAA-activated ion channels?
AMPA
NMDA
What is AMPA responsible for?
fast nociceptive transmission
What is NMDA responsible for?
sustained depolarization **big focus of chronic pain research.
What are 2 excitatory NT that act via channel activation & 2nd messenger systems?
CGRP
Substance P
What is CGRP involved in?
peripheral vasodilation
What is Substance P involved in?
it is a modifier & is co-released w/ glutamate & is involved in neurogenic inflammation
Inhibitory Amino Acids (IAA) are NT released from what? What are the 2 main types of IAA?
2 main types of IAA:
GABA
Glycine
**released from spinal interneurons
Aside from GABA & Glycine what are other NT that are released from spinal interneurons?
opioids
ACh
What are the 2 main NT released from supra spinal sources?
Serotonin
NE
