Quiz 3 Pain Manament Flashcards
What are the two types of pain?
Nociceptive and Neuropathic
Which of the two types of pain does Opiates work best for?
Nociceptive pain
What kind of meds work best for Neuropathic pain?
Tricyclic Antdepressants and Neuropathic meds like Lyrica, Neurontin, Carabmazipine.
Describe the basic Nociception pathway
Stimulation - noxious stimulus releases neural chemicals that also stimulate other nociceptors
Transmission - Action potential moves from site of stimulus to the dorsal horn of the spinal cord then to the CNS
From Dorsal horn, neurotransmitters are released (Glutamate, Substance P, Calcitonin related peptide)
Perception - Concious experience of pain releayed through thalamus. Higher cortical structures transmit pain
Modulation - inhibition of impulses via the brainstem by releasing endogenous opioids, serotonin, NE, GABA
What are some common characteristics of Neuropathic pain?
Burning, Tingling, Shocks, Hyperalgesia, Allodynia (pain from stiumuli that is not normally painful)
What does PQRST stand for when assessing pain?
P - Palliative and provocative factors (agravating or alleviating)
Q - Quality
R - Radiation
S - Severity (can use pain scale)
T - Temporal relations (??)
Analgesia produced by neuraxial opioids is not associated with?
- SNS denervation
- Skeletal muscl weakness
- Loss of proprioception
What lab test can be used to measure pain?
NONE. Pain is subjective. Need to evaluate for outward signs of pain like grimacing, guarding, HTN, tachycardia, ….
What is neuraxial opioids?
Placement of opioids in epidural or subarachnoid space.
Where are Opioid receptors located?
the brain, spinal cord, and GI Tract
What are the 4 types of Opioid pain receptors?
Delta, Kappa, Mu, Nociceptive
What are the opioids routes of uptake into the body from an epidural?
- Diffusion of the drug across the dura to gain access to mu opioid receptors
- systemic absorption
- uptake into the epidural fat
What happens when the Mu1 receptor is stimulated?
Analgesia, Miosis (constricted pupil), Dependence
How long until CSF concentration of fentanyl will peak?
20 minutes.
What happens when the Mu2 receptor is stimulated?
Respiratory depression
Euphoria
Reduced GI motility
Dependence
**Spinal Analgesia**
Where do opioids work on the nerve - Pre or Postsynapse?
They work on both the Pre and Postsynapse.
They help to hyperpolarize the cell to decrease pain sensation
NMDA will pump in excess Ca++ into cell to hyperpolarize. Mu receptor will stimulate pump to push K+ out of cell.
What can happen if NMDA receptors are overstimulated by glutamate?
Can lead to Neuropathic pain
What are four classic side effect for Neuraxial opiods?
- Pruritus
- Nausea and vomiting
- Urinary retention
- Depression of ventilation
What will occur if epi is added to opioid epidural does?
Decrease systemic asorption of opioid but not effect diffusion across dura into the CNS.
What are the point for opioid use intrathecal?
- Vascular absorption is limited and clinically insignificant
- Cephalad movement of opioid in CSF depends on lipid solubility
- Coughing or straining can affect movement in CSF
- Positioning has no affect.
How does Naloxone work?
Nonselective antagonist at all 3 opioid receptors.
How is Nalooxone metabolized and what is the metabolite?
Hepatic microsomal enzyme and naloxone-3-glucuronide.
T or F - Opioids must exist in the ionized state in order to form a strong bond at the opioid receptor?
True
What is the peak effect of morphine after IV administration?
15-30 mins