Pain- Ross Flashcards
Nociceptor is the ________ receptor detecting the stimulus of heat/cold, Ph, mechanical disruption (bringing pain into the spinal cord _______ the brain via __________ tract)
afferent
towards
spinothalamic tract
A-alpha and A-beta carry, these three things to Medulla
vibration, stretch, proprioception
2nd order neuron bring signals from the _____ to _______
medulla to thalamus
2nd order neuron bring signals from the _____ to _______
thalamus to somatosensory cortex
T/F: A-delta and C fibers carry nociceptor sense to the medulla then thalamus then cortex
True
A –alpha and A-beta Dorsal column is the _______ ________ pathway
Medial lemniscus pathway meaning: system that conveys sensations of fine touch, vibration, two-point discrimination, and proprioception (position) from the skin and joints to the brain
pain receptors are called _______
nocireceptors
What type of pain?
A-beta & A-alpha:
fast, light touch
What type of pain?
A-delta
sharp pain because they are myelinated
What type of pain?
c fibers
(unmyelinated) slower, dull burn pain
1st order neuron resides in _______ _____ _______; 2 arms one in the periphery and the other goes into SC at dorsal columns it goes up then _______ over, continues through the dorsal column to medulla where synapse at dorsal column nuclei
dorsal root ganglion
crosses over
(crosses from one side to the other so pain on R side of body is processed on the L side of the body)
2nd order neuron carries info to the _______
thalamus
3rd order neuron goes from thalamus to __________ _____ (location of pain), cingulate cortex: interpretation of pain and or insular cortex (limbic brain) emotional reaction to pain
somatosensory cortex
________ decreases activation and makes it easier to feel pain while serotonin
prostaglandin
what three things make the pain threshold go up and hard to feel pain
serotonin, thromboxane and endorphins
What is the convergence theory?
Convergence theory is when a visceral and somatic afferent converge on the same are of dorsal horn, the brain can not distinguish between the 2 and pain can be felt in a different location
What are some local effects nociceptors can have?
edema, vasodilation and hyperalgesia (enhanced sensitivity to pain)
What is the cortex influence of pain?
The cortex probably influences pain via several mechanisms. It has been proposed that the cortex may reduce pain by interrupting the transmission of noxious information from the spinal cord level by activating descending pain modulatory systems located in the brainstem
It’s the ________ that sends signals to somatosensory cortex, cingulate cortex and insular cortex. The ______ interprets the signal of pain (emotional/rational input) and modulates it.
thalamus
Cortex
What is the purpose of endorphins?
Endorphins turn on/off cells that inhibit (green) or facilitate control of nociceptive signals (red)
Where are the four places we can influence pain?
- at nociceptor
- in dorsal horn
- PAG
- thalamus
What happens at the PAG?
At baseline the cortical influence on pain is blocked by an inhibitory neuron. So initially when you hit your arm there is no cortical modulation of the pain, only when the hypothamus , insular cortex or cingulate cortex signal to an inhibitory neuro to inhibit the baseline blockage of signal (inhibitory neuron) do cortical influence take effect. This is mediated by endorphins.
At the dorsal horn, the modulation of pain is from the:
Modulation of pain is from serotonin, norepi, opioids, gaba receptors
If there is a local issue with pain detection what can we use to help?
NSAIDS, nerve blocks and local anesthesia can be helpful
If there is a transmission issue with pain transmission what can we use to help?
Opioids acetaminophen, gabapentin and tricyclic anti-depressants can help
If there is an issue with pain expression, what can be helpful?
Opioids, benzo, sedative, hypnosis, and distraction can be helpful
T/F: Placebo effect is real, the brain will produce endogenous opioids to modulate pain.
T
**What is a major side effect of morphine?
hypotension and nausea and histamine release
What is the IV dose or morphine and PO?
IV: 0.1 mg/kg
PO: 0.3 mg/kg
Short acting 10-30 min
What is a major side effect of hydromorphone (diludid)?
EUPHORIA *makes people feel high
What is the IV dose for hydromorphone and IM?
IV: 0.015 mg/kg
IM: 1-2 mg/kg
Longer acting about 2-4 hr for IM, shorter for IV
**What is a major side effect of fentanyl?
> 5 mcg can cause chest wall ridigity
**used for breakthrough pain; opioid tolerant cancer - wait 2 hrs before treating another episode
What can you increase the fentanyl dose by per episode?
100 micrograms per episode
What is the IV dose for hydromorphone and nose spray?
IV: 1 mcg/kg lasts about 60 min
Nostril Spray: highly addictive
**Oxycodone side effects?
Possible inadvertend acetaminophen overdose with combination agents
**same as the side effects for hydrocodone
What is the dosing for oxycodone?
5-10 mg PO
OR
30 mg PR
Side effects of codeine (natural alkaloid)?
High incidence of GIside effects
Some patients cannot metabolize it
What is Ross’s fav pain med?
Oxycodone
This as an alternative to a narcotic for acute pain especially neuropathic similar to gabapentin
ketamine
What are two topical meds that can be used in back pain?
lidocaine, capsacin
What are some HA meds?
Headache: phenothiazines (Compazine, ergotomines (sumatriptan), anti-psycotics (Haldol), anti-seizre (valproate)
