L3: Intro to Pain Management (Granone) Flashcards
negative consequences of pain
hyperalgesia sympathetic stimulation decreased appetite increased anesthetic drug requirements unseen CNS changes
adaptive inflammatory pain
spontaneous pain and hypersensitivity to pain in response to tissue damage and inflammation. Occurs with tissue trauma, injury, surgery
adaptive nociceptive pain
transient pain in response to a noxious stimuli. Small aches and pains that are relatively innocuous and that protect the body from the env.
allodynia
pain caused by a stimulus that doesn’t normally result in pain
-manifestation of peripheral n. and tissue injury that induces changes in the CNS
hyperalgesia
an increased response to a stimulus that is normally painful
-localized inflammation at the site of tissue injury, in peripheral tissues, causes hyperexcitability of nociceptors due to a reduction in threshold and an increased responsiveness to noxious stimuli (peripheral sensitization)
maladaptive pain - functional
hypersensitivity to pain resulting from abnormal processing of normal input. Is chronic
maladaptive pain - central neuropathic pain
pain initiated or caused by a primary lesion or dysfunction in the CNS. Often called “central pain”
nociception
the process of detection of potentially or actually damaging stimuli and the transmission of that information to the brain. Made up of 5 components:
1) transduction
2) transmission
3) modulation
4) projection
5) perception
transduction
the conversion of noxious stimuli to an action potential at the level of nociceptors
transmission
the propagation of action potentials by primary afferent neurons to the spinal cord
modulation
the process by which nociceptive information is augmented or inhibited
projection
the delivery of nociceptive information from the spinal cord to the brain
perception
the integration of the nociceptive info by the brain. The overall conscious emotional experience of pain
does nociceptor activation = pain?
NO!
nociceptor
-unspecialized n. cell endings that initiate the sensation of pain, sense and transduce electrical signals at the site of tissue disruption
graph slide 4
:)
windup
the perceived increase in pain intensity over time when a painful stimulus is repeatedly delivered above a critical rate
- occurs as a frequency-dependent increase in the excitability of spinal cord neurons, specifically afferent C fibers (central sensitization)
- challenging to treat
pain pathway
1) sensory pain receptors located on peripheral ends of sensory n. fibers convert painful chemical or physical stimuli into action potentials
2) APs open gated ion channels
3) depolarization of cell membrane and an AP
stimuli that have potential to cause cell damage
heat
vibration
pressure
chemicals
3 mechs. that release of inflammatory mediators leads to peripheral sensitization (pain amplification)
1) depolarization of pain sensing nerve endings
2) lowering the threshold in which depolarization occurs in primary afferent nerves
3) vasodilation and inc. permeability of blood vessels that results in an increased # of leukocytes and inflammatory mediators at the site of injury
once an AP is triggered, signal is sent to:
dorsal horn of spinal cord where pain signal is processed.
synapses of importance for this lecture
- neurons from ascending tracts to the brain
- alpha-motor neurons which serve as efferent limb of reflex actions in response to painful stimuli
pain signals from spinal cord sent to:
contralateral thalamus –> somatosensory cortex of the brain
slide 6**
:)
somatosensory cortex is responsible for:
1) discrimination of pain signals
2) recognition, learning and memory of painful experiences
somatic pain
pain related to the wall of the body cavity
visceral pain
pain that is often poorly localized and associated with mechanical stimuli (ie. stretch of viscera), ischemia, chemical and thermal stimuli
-accompanied by changes to somatic m. tone and autonomic responses
signs of pain in horse
unwillingness to use limbs flank-watching restless attitude change posture facial expression interaction w/ people
T/F: HR and RR are poor indicators of pain in hospitalized dogs
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simple descriptive pain scale
- first pain scale to be used in animals
- 3 to 5 point scale w/ answers of mild, moderate to severe (open to interpretation)
numerical rating scales
-use numeric units which are assigned to different categories of behaviors
University of Melbourne Pain Scale
used to assess post-op pain
-fails to capture full details of a case
CSU Pain Scale
used to assess pain clinically
-fails to capture full details of a case
Visual Analog Scale (CAS)
- semi-objective
- consists of 100mm line (0 to 100 pain)
- prone to observer bias
Glasgow Composite Measurement Pain Scale (CMPS)
- validated, reliable results obtained
- consists of questionnaire that examines numerous behavioral traits and then pain score is derived
- takes a long time to complete
Short form CMPS
- shorter version of CMPS
- allows clinician to provide the patient proper analgesia based on the overall score
- only takes 5 mins
benefit of preemptive analgesics
provide the benefit of a decreased drug requirement during maintenance and recovery of anesthesia
multimodal therapeutic plan
- includes use of drugs that are directed at treating specific mech. of pain
- allows for the reduction in the dose of each drug
- reduces potential side effects
