Pain Flashcards
Definition and Example of: Allodynia
Pain due to a stimulus that does not normally produce pain
A normally nonharmful stimulus is perceived as painful
ex: Fibromyalgia
Define Algesia
increased sensitivity to pain
Definition and Example of: Algogenic
Pain producing
A stimulus that is normally expected to produce pain.
ex: surgical incision
Definition and Example of: Analgesia
No pain is sensed in response to a stimulus that produces pain
ex: opioid pain relief
Definition and Example of: Dysesthesia
Abnormal and unpleasant sensation, whether evoked or spontaneous
ex: burning sensation from diabetic neuropathy
Definition and Example of: Hyperalgesia
Exaggerated pain response to a painful stimulus
ex: opioid-induced hyperalgesia (Remifentanil)
Definition and Example of: Neuralgia
Pain in the distribution of peripheral nerve(s)
Pain localized to a dermatome
ex: herpes zoster (shingles)
Definition and Example of: Neuropathy
Impaired/abnormal nerve function
ex: silent myocardial ischemia from diabetic neuropathy
Definition and Example of: Paresthesia
Abnormal sensation (not necessarily painful like Dysesthesia) described as pins and needles
ex: Nerve stimulation during regional anesthesia
What are the pain-modulating neurotransmitters? Which are excitatory and which are inhibitory?
Excitatory: Substance P and Glutamate
Inhibitory: Glycine, GABA, Enkephalin, Serotonin, Norepinephrine
What receptors does Substance P bind to?
Neurokinin 1 (NK-1)
Neurokinin 2 (NK-2)
What receptors does Glutamate bind to?
NMDA
AMPA
Kainite
mGluRs (mGluRs=metabotropic glutamate receptors)
What receptor does Glycine bind to?
Chloride Linked (GlyR = glycine receptor)
What receptors does GABA bind to?
GABA A, GABA B, GABA C
What receptors does Enkephalin bind to?
Mu and Delta Receptors (opioid receptors)
What receptors does Serotonin bind to?
5-HT (5-HT1, 5-HT2, 5-HT3)
What receptors does Norepinephrine bind to?
Alpha 2 Adrenergic
Your patient is opioid tolerant. What are some non opioid medications we can give that will affect antinociception in the dorsal horn?
NMDA Antagonists - Ketamine - (glutamate)
If you want to target sodium channel receptors to inhibit pain, what medication(s) might you use?
Local Anesthetics such as Lidocaine
Difference between somatic and visceral pain
Somatic pain travels through the A Delta Fibers. Fast, sharp pain, easily localized.
Visceral pain travels through the C fibers. Often dull, achy, difficult to localize pain. Slower transmission.
What is the mechanism and action of Gabapentin
Believed to block the alpha 2 delta (α2δ) subunit of the presynaptic voltage- gated calcium channels in the CNS, thereby preventing excitatory neurotransmitter release.
Where is the substania gelatinosa located?
In the dorsal horn and in rexed lamina II
Where does gate control of pain occur?
The substansia gelatinosa - rexed lamina II
Describe Central sensitization and wind up
Genetic and cellular changes in the dorsal horn coupled with changes in the dorsal root ganglion in response to inflammatory mediators. Second order, neurons, develop, hyperactivity, and lower threshold for activation.
Becomes the rentrant pathway for pain. We target these areas with opioids, but they can actually cause hyperalgesia over time. Why we need multimodal analgesia.
Windup occurs via which receptors?
NMDA
What opioid receptors are there in the spinal cord?
Mu (big one) as well as delta and kappa
If taking care of kid, what age can you use the smiley face pain assessment tool?
Children greater than 5 years old
When are kids are able to use a standard adult pain scale?
7-8 years old
What are our endogenous opioid receptor binding agents
enkephilins, dynorphins (endorphins)
Where does pain modulation occur in the spinal cord?
Dorsal Horn
Where does glutamate work / is found in the spinal cord?
primary excitatory transmitter found within the cerebral cortex, the hippocampus, and the substantia gelatinosa of the spinal cord.
Patients taking gabapentin are kept on their dose before and after surgery. why?
Because they can experience withdrawl
What type of drug is Dexmeditomidine? What is its action?
Alpha 2 Agonist
Decreases transmission and release of the presynaptic neurotransmitter norepinephrine
How does magnesium help pain management?
Also targets NMDA receptor - antagonist
From smashed finger to the brain - describe the pain pathway
A delta fibers bring pain stimulus to Dorsal Root Ganglion, then to the dorsal horn of spinal cord, it decissates, an interneuronal synpase occurs and then the signal travels up the lateral spinothalamic tract to the thalamus, then cortex.
How do Endogenous opioids (enkephalins) inhibit first and second order neurons from transmitting pain?
Inhibits pain transmission in the dorsal horn, decreases substance P (&glutamate?) release in the dorsal horn.
What is pain transduction
Transduction is the transformation of a noxious stimulus (chemical,
mechanical, or thermal) into an action potential.
What are some of the chemical noxious stimuli that trigger transduction?
Prostaglandins
Bradykinin
Serotonin (can potentiate bradykinin)
Substance P
Histamine
Adenosine
Leukotrienes
What is Substance P? What fibers release it?
An excitatory neurotransmitter peptide found and released from the peripheral afferent nociceptor C fibers.
Substance P is involved in what kind of pain?
Slow, chronic pain.
When Substance P acts on the Neurokinin 1 Receptor what ensues?
Vasodilation, Extravasation of plasma proteins, Degranulation of mast cells, and Sensitization of the stimulated sensory nerve.
Glutamate is invilved in what kind of pain?
A delta fibers - fast, sharp pain
Who and where is Complex Regional Pain Syndrome most common?
Postmenopausal Women (peak age 40)
Most commonly in the upper limbs
What are some inciting events that can cause Complex Regional Pain Syndrome?
Fractures, Crush Injuries, Sprains, and Surgery
