Pain Management Flashcards
Define: Algesia
Increased sensitivity to pain
Define: Algogenic
Pain producing
Define: Allodynia
A normally non harmful stimulus is perceived as painful
Define: Analgesia
The absence of pain in the presence of a normally painful stimulus
Define: Dysethesia
An unpleasant painful abnormal sensation, whether evoked or spontaneous
Define: Hyperalgesia
A heightened response to a normally painful stimulus
Define: Neuralgia
Pain in the distribution to a peripheral nerve(s)
Define: Neuropathy
An abnormal disturbance in the function of a nerve(s)
Define: Parasthesia
An abnormal sensation, whether spontaneous or evoked
What is the time length to be termed acute pain
< 1 month
What is the time length to be termed chronic pain
> 3 months
What is nociceptive pain
Stimulation of SPECIFIC nociceptors
- Somatic
- Visceral
What is non-nociceptive pain
- Neuropathic
- Inflammatory
Describe Somatic pain
- Identifiable _____
- Tissue damage is from…
- How is the pain described?
Identifiable focus
Tissue damage – chemical release modulates pain
Well localized, sharp, hurts at area
Describe Visceral pain
- localized of diffuse?
- How is pain described?
- Associated with what autonomic reflexes
- What is an example
Diffuse, referred
Dull, cramping, squeezing
Autonomic reflexes - nausea, vomiting, diarrhea
Ex. Distention of organ capsule, obstruction of a hollow viscus
Neuropathic pain - damage to peripheral or central neural structures resulting in…
an abnormal processing of painful stimuli
Neuropathic pain is dysfunction of the…
central nervous system
How is neuropathic pain described
Burning, tingling, shock like
Describe the process of inflammatory pain
Sensitization of the nociceptive pathway from multiple mediators being released at the site of the tissue inflammation WITHOUT neural injury
What is the order of nociceptive pain transmission
Transduction, Transmission, Perception, Modulation
Define: Transduction
Stimuli is converted to action potential
Define: Tranmission
Action potential conducted through nervous system
First-, second-, third-order neurons
Define: Perception
Integration of painful input into the somatosensory and limbic cortices
Define Modulation
Altering afferent transmission along pain pathway
Where does modulation take place at?
Most common in dorsal horn
Transduction is the transfer of ____ to an ___
noxious stimuli to action potential
During transduction, which fibers transmit sharp/fast pain?
A-delta fibers – myelinated, fast 6-30 m/s
reflex alert
During transmission, what fibers transmit dull, buring, throbbing, aching pain?
C fibers – unmyelinated, slow 0.5-2 m/s
C fibers respond to which type of injuries?
mechanical, thermal, and chemical injuries
known as “polymodal fibers”
When peripheral tissues (skin, bone, and viscera) receive chemical, thermal, or mechanical stimuli or are traumatized by either surgery or injury, a series of biochemical events takes place in peripheral pain transduction. These events include release of chemicals mediated from the inflammatory response and the release of neurotransmitters from _____
nociceptive nerve endings.
Transduction Chemical Mediator:
Substance P
1. Found & released from __ fibers and are involved in _____ pain
- G-protein linked ______
- What does it cause? (4 things)
- C fibers & slow/chronic pain
- G protein-linked neurokinin-1 receptor
- Vasodilation, extravasation of plasma proteins, degranulation of mast cells, sensitization of stimulated sensory nerve
Transduction Chemical Mediator: Glutamate 1. CNS or PNS? 2. Which fibers? 3. Effect fast of slow? 4. What is the pain like?
- CNS
- A-delta, and C fibers
- Instantaneous effect
- Fast/sharp
Transduction Chemical Mediator:
Bradykinin
1. Peptide - notably _____
2. Direct stimulating effect on peripheral nociceptors via _____ receptors
- notably algesic
2. bradykinin (B1/B2)
Transduction Chemical Mediator:
Histamine
1. Amine is release from….. (3) via ____
2. Causes ____
- mast cells, basophils, and platelets - via substance P
2. Edema & vasodilation
Transduction Chemical Mediator:
Serotonin (5-hydroxytryptamine [5-HT])
1. Amine stored and released from ____ after tissue injury
2. Algesic effect on ______
- platelets
2. peripheral nociceptors
Transduction Chemical Mediator: Prostaglandins, thromboxanes, leukotrienes 1. Synthesized from \_\_\_\_ 2. Hyperalgesia-PGs sensitize \_\_\_\_\_\_ 3. Associated with \_\_\_\_\_ pain
- COX-1 and COX-2
- peripheral nociceptors
- Chronic
Transduction Chemical Mediator: Cytokines 1. Released in response to \_\_\_\_ 2. Cytokines include \_\_\_\_ 3. Leads to increased production of
- tissue injury
- interleukin-1B, interleukin-6, and tumor necrosis factor
- Prostaglandins
Transduction Chemical Mediator:
Calcitonin gene-related peptide (CGRP)
1. Peptide released from AFFERENT __ fibers
2. Causes local cutaneous ____ (3)
- C fibers
2. vasodilation, plasma extravasation, and sensitization
Transmission is action potential transmitted from
periphery to CNS
Multiple pathways (ex. Spinothalmic [anterolateral] tract)
Perception occurs once signal is recognized by
various areas of the brain
Amygdala, somatosensory areas of cortex, hypothalamus, anterior cingulate cortex
Modulation is altering neural afferent activity along pathway, how does it do this?
Suppress (inhibitory)
Enhance (excitatory)
What is considered the bodys analgesia system?
Descending efferent pathways –> from the Suppress (inhibitory)
Name the excitatory transmitters
Substance P
Glutamate
Name the inhibitory neurotransmitters
Glycine GABA Ankephaln Serotonin Norepinephrine
NSAIDs
For what type of pain?
Has what properties?
mild to moderate pain
Anti-inflammatory, antipyretic, and analgesic properties
What does NASIADs inhibit?
Inhibit COX, thereby stop conversion of arachidonic acid to prostaglandins
Ketorlac (Toradol)
what is its MOA?
Nonselective COX inhibitor
Ketorlac (Toradol)
30mg IM equivalent to
Dont admin longer than
Contraindications (7)
12 mg IM Morphine
5 days
coagulopathies, renal failure, active peptic ulcer disease, GI bleeding, Hx of asthma, hypersensitivity to NSAIDS, sx with high potential for post-op bleeding
Acetaminophen Reduced \_\_\_\_\_ synthesis What are the main properties Has minimal \_\_\_\_ Contraindicated in
Prostaglandin
Analgesic and antipyretic
Minimal anti-inflammatory
Liver Failure
What is the max daily doses for Acetaminophen
Max dose for 24 hrs is 4g
Opioids bind to and activate ______ coupled receptors in the _____ and ____
G-protein
Periphery and CNS
Where are the opioid receptors in the CNS
Dorsal Horn, specifically Rexed lamina II (substancia gelatinosa), periaqueductal grey, medial thalamus, amygdala, limbic system
Where are the opioid receptors in the periphery
afferent sensory nerve fibers, GI tract, lungs, joints
Opioids - what do the Mu, Delta & Kappa receptors do pre-synaptically?
decrease adenylate cyclase activity > inhibiting calcium channels >
decreased excitatory neurotransmitters
Opioids - what do the Mu, Delta & Kappa receptors do post-synaptically?
Increased potassium conductance > hyperpolarizes >
Inhibits excitatory neurotransmission
What is the NMDA antagonist we use?
Ketamine – prevents activation of NMDA receptor (NMDA is excitatory)
NMDA is associated with
“wind-up”
What are the alpha-2 adrenergic agonists
Clonidine and Precedex
Clonidine & Precedex interact with ____ alpha 2 receptors, centrally and peripherally
Inhibits ____ and decreased ____
Activates postsynaptic ____ channels and inhibits presynaptic ____ channels which decrease neurotransmitter release
G protein-coupled
adenyl cyclase and decreased cAMP
potassium/calcium
Anticonvulsants (gabapentin [Neurontin] and pregabalin [Lyrica]) are used for what type of pain? How does it work?
Neuropathic pain syndromes
Inhibit neuronal excitation and stabilize nerve membranes
Should you continue Anticonvulsants (gabapentin/pregabalin) with surgery?
yes
How do antidepressants work?
Block the reuptake of serotonin and norepinephrine in CNS, increasing availability
Should you continue Antidepressants with surgery?
yes
How do corticosteroids work?
Anti-inflammatory – decrease cytokine and prostaglandin release
Should you continue corticosteroids with surgery?
yes - possible stress dose
How does methadone work?
Synthetic opioid, NMDA and opioid receptor action
Should you continue methadone with surgery?
continue?
How long does it take to detox from methadone?
30 days to detox from methadone
20-40 mg range
What are the 3 subdivisions of painful stimuli
Painful stimulation without tissue damage
Tissue damage without nerve damage
Nerve damage
Painful stimulation without tissue damage:
Withdrawal from stimulation, stop damage, local event
…
Tissue damage without nerve damage:
Pain persists after withdrawal, intensified response to tactile stimulation, sensation of pain will spread, release of response mediators
…
Nerve damage:
Direct damage to nerve, can be ___ or ____
demyelinating or axonal
3 anatomic regions associated with pain
Peripheral
Spinal
Cerebral
Chronic pain treatment must do what?
Must address source!
The dysfunctional inhibitory mechanism in the peripheral and spinal nervous system
Address the dysfunctional pain perception in the cerebrum
Types of chronic pain:
Psychogenic
unable to validate or find source
term falling out of favor
Types of chronic pain:
Inflammatory
Tissue damage resulting in pain and release of inflammatory mediators
Inflammatory produces capillary vasodilation, smooth muscle contraction and…
promote synaptic transmission of pain impulses to CNS (histamine, bradykinin, and substance P)**
Types of chronic pain:
Neuropathic
Nerves damaged, pain radiates along dermatome
Neuropathic pain commonly leads to …
Pain is ____ and not managed well with ___
Allodynia
persistant/NSAIDs
(ex. shingles)
What is windup
Cyclic response to pain that leads to abnormal pain response
Patients often labeled as “drug seekers”, “chronic complainers”, “crazy”
While can be psychological, not always is
Treating chronic pain is
Multimodal
- Remove or treat stimulus
- Reset the inhibitory mechanism of central spinal area
- Address psychological impact of pain in cerebral area
In the periphery, neuropathic pain is thought to include both ___ and ___ fibers
A (fast) and C (slow) nerve fibers
What is the normal sequence of response to pain in the periphery
Stimulation > Substance P > Neurokinins > Action potential sent to CNS
NMDA receptors inactive (stabilized by magnesium)
What is the abnormal (chronic pain) sequence of response to pain in the periphery
Magnesium displace > NMDA activated > calcium ions enters cells
EXAGGERATED release of substance P and excitatory amino acids
Spinal pain has many complex features. Chronic pain may trigger inappropriate activation of ____ creating negative consequences
neuropeptides
Cerebral pain has various regions involved in pain modulation. There is a psychological component evident with
Placebo effect
What medication may be helpful to prevent windup in chronic pain patients? what is the consequence to this med?
Windup is from NMDA activation
Pretreat with ketamine (blocks NMDA activity)
Concern for hallucination and vivid dreams
Muscle Relaxants:
Cyclobenzaprine (Flexeril)
When does it become ineffective?
Used for..
ineffective in a few weeks
Short term symptomatic relief
Muscle Relaxants:
Carisoprodol (Soma)
Has the potential for
dependence, tolerance, mental impairment
Muscle Relaxants:
Baclofen
Is NOT for use in..
Specialized for
What can occur with use?
NOT for use in chronic pain
specialized (cerebral palsy, MS)
Withdrawal symptoms can occur
(Respiratory failure, hemodynamic changes, seizures, delirium)
