Pain Flashcards
Chemical mediators, ______and _____ is released from pancreatic ______ neurons and can lead to visceral cancer pain
Substance P and calcitonin gene-related peptide (CGRP)
vagal afferent neurons
The pancreas has sensory innervation via ___
vagal branches
and
axons from splanchnic nerves and celiac plexus
Central alpha-2-receptor agonists cause (analgesia/pain)
analgesia
- sympatholysis
Lumbar sympathetic block targets the _______, along the anterolateral border of the lumbar vertebrae. _____ muscle is located posteromedial to the ganglia, and is often injected by contrast.
lumbar sympathetic ganglia
Psoas major
Most common indication for epidural steroid injection is ____
- Radicular pain caused by herniated disk
- Spinal stenosis
*Radicular pain responds favorably to ESI
Cauda equina syndrome affects ____ dermatomes
S3-S5
- saddle anesthesia
(True/False) localized pain is nototoriously difficult to treat
True
- TENS, ESI do not have good results
Why is treating phantom limb pain so difficult?
Lack of RCTs
Order from most to least common nerves affected by herpes zoster
- Thoracic
- Opthalmic division of trigeminal n (V1)
- Maxillary division of trigem n. (V2)
- Cervical spinal roots
- Sacral spinal roots
Patients with trigger point myofascial pain often have _____.
Painful limitation of ROM
Spasm
Stiffness
Weakness
What pain syndrome is associated with hypermobile muscles and can be made worse with trigger point injections??
Fibromyalgia
How do TCAs provide analgesia in non-cancer related pain? (4)
- SSRI
- NMDA antagonist
- mu-opioid receptor agonist
- Na-K channel blocker
TCAs are mu-opioid receptor (agonists/antagonists)
agonists
*naloxone is a mu-opioid receptor antagonist
Lower extremity complex regional pain syndrome (CRPS)
- (autonomic dysfunction, burning pain, cyanotic, edematous, glossy skin ect)
is treated with_______
serial lumbar plexus sympathetic block
Common side effect of serial lumbar plexus sympathetic block
Failure of ejaculation
(not erectile dysfunction)
- sympathetic dependence of ejaculation
Why is diarrhea associated with celiac plexus block?
(T5-T12): Supplies innervation to all intraabdominal organs and most of bowel
_______ is an NMDA antagonist that may be used in the treatment of CRPS
Memantine
How does NAC work against acetaminophen toxicity?
N-acetylcystine: provides cysteine for replenishment of hepatic stores, which enhances elimination pathway
(True/False) Epidural steroid injections for lumbar radiculopathy have a direct correlation duration of symptoms. The Longer the disorder, the better it works.
False
- inverse
The more acute the symptoms, the higher predictor of success
Inhibitory neurotransmitters: inhibit central nociceptor terminals -> reducing excitatory transmitter release
Glycine
- acts at spinal levels
GABA
- acts at higher levels
Cation channel gating or excitation occurs as a result of ____ stimulation of ______ in peripheral tissues
noxious stimulation of the primary afferent neurons (ie. nociceptors)
Excitatory neurotransmitters that lead to opening (gating) of cation channels in the presynaptic nociceptor terminals
Glutamate,
substance P,
calcitonin gene-related peptide
Patients from (higher/lower) socio-economic backgrounds are more sensitive to pain
lower
- worse coping mechanisms
- worse understanding
The stellate ganglion is made of the ______ and _____ sympathetic ganglia and lies in close proximity to the carotid artery, internal jugular vein, lung, and brachial plexus
Inferior cervical
First thoracic sympathetic ganglia
Side effects of stellate ganglion block
- Vasovagal reactions
- need to differentiate form intravascular, epidural, spinal injections - Horner syndrome
- Ptosis, miosis, anhidrosis, enopthalmos
______ is the most common complication of celiac plexus blockade. It is most often used for ____
#1: Orthostatic hypotension - splanchnic vasodilation by sympatholysis #2: diarrhea
Pain caused by unresectable pancreatic cancer
When there is impingement of the spinal CORD itself that results in functional impairment such as weakness, numbness, or abnormal reflexes, the diagnosis is (radiculitis/myelopathy)
Myelopathy
*radiculitis indicates inflammation of spinal NERVE ROOT, which may lead to pain in that nerve’s distribution WITHOUT weakness
When there is impingement of the spinal NERVE ROOT that results in nerve pain with functional impairment such as weakness, numbness, or abnormal reflexes, the diagnosis is (radiculopathy/myelopathy)
Radiculopathy
*myelopathy is at the spinal cord, not the spinal nerve root
Herpes zoster can cause blindness in immunocompromised pts if the ______ nerve is affected
trigeminal nerve
Meds approved for fibromyalgia
Duloxetine - SNRI, additional antinociceptive effect
Milnacipran - SNRI, additional antinociceptive effect
Pregabalin - a-2/delta calcium channel modulator
How does neuraxial fentanyl work and why is it so fast?
activation of mu receptors in the substantia gelatinosa in the dorsal horn of the spinal cord
- where they inhibit release of excitatory neurotransmitters (substance P and glutamate)
What is more concerning, lipophilic fentanyl or hydrophilic morphine/hydromorphone
Hydrophilic
- ascend in CSF to reach resp centers of the brainstem
- also works at dorsal horn of SC
*lipophilic opioids work at dorsal horn of SC and through systemic absorption
Epidural (hydromorphone/fentanyl) has less cephalic spread
fentanyl
- more lipophilic, and absorbed systemically by surrounding fat
- the more lipophilic, the shorter its duration in the epidural space
*hydromorphone and morphine is hydrophilic
First order neurons secrete _____ in the dorsal horn as a chemical mediator of pain signaling.
Substance P
Wind-up phenomenon
exponentially progressive increase in firing of neurons w/ repeated stimulation
a ________ is the next step for failed medical management of complex regional pain syndrome
one sided diagnostic sympathetic block
- sympathectomy alone w/o analgesia
What is complex regional pain syndrome?
syndrome that produces spontaneous pain
- Hyperalgesia or allodynia
and is associated with autonomic dysfunction
Type 1: no nerve damage
- trivial injury, sprain, burn
Type 2: nerve damage present (usually to major nerve trunk)
- traumatic injury, gsw, knife wound
a ________ is the last resort for treating complex regional pain syndrome and is indicated for refractive neuropathic pain rather than nociceptive pain
Spinal cord stimulator
- short electrical bursts to dorsal column of spinal cord
Thigh dermatomes
- L1
- L2
- L3
- L1: Along inguinal ligament
- L2: Medial/lateral upper thigh
- L3: Medial/lateral lower thigh (does not include knee)
Thigh dermatomes
- L4
- L5
- S1
- L4: lateral lower thigh, knee, and 1/2 of big toe
- L5: Lateral calf and toes 1.5-4
- S1: 5th toe
How does pKa affect local anesthetics?
Associated with speed of onset of drug
- sodium bicarb can be added to LA
_______ is the best tx for a pt with an acute lumbosacral radiculopathy
NSAIDs
In pt with an acute lumbosacral radiculopathy, what should be done first, imaging or treatment?
Conservative treatment
- then CT or MRI if needed
- XR does not pick up soft tissues like herniated disc
Neuropathic pain occurs following injury to (afferent/efferent) pathways and involve (central/peripheral) mechnanisms.
afferent
-> hyper-excitability
Both central and peripheral components
How does gabapentin and pregabalin work?
a-2-delta ligands that bind the subunit on VG calcium channels ->
prevent release of nociceptive neurotransmitters
For electrical pain signals to pass, the NMDA receptor must be open. What are common NMDA receptor antagonists?
Ketamine
Nitric oxide
Methadone
Sympathetic plexus blocks are ideal interventions for patients with _______ refractive to medical therapy. A good marker of successful sympathetic block is ________.
regional neuropathic pain with sympathetic mediation
Increase in limb temp by 2-3 degrees Celsius as blood vessels dilate
Most common cause of seizure immediately after LA injection during a stellate ganglion block?
Vertebral or carotid artery injection
The stellate ganglion is located at the level of _____ transverse process. The stellate ganglion block is often used in the tx of _____
C7
- fusion of the inferior cervical and first thoracic ganglions
Complex regional pain syndrome
Bupivacaine, d/t its ______ can cause CNS toxicity at lower doses than many other local anesthetics
potency and lipid-solubility
Local anesthetics belonging to the (ester/amide) class, more commonly result in hypersensitivity reactions d/t their ______
Ester
PABA metabolite
The nerve supply to the lower extremity is derived from the _____ and ____ plexus
Lumbar and sacral
The lumbar plexus gives rise to ______ nerves
Femoral n
Obturator n
Lateral femoral cutaneous n
The sacral plexus gives rise to ______ nerves
Posterior cutaneous n of the thigh
Sciatic n
A sciatic peripheral nerve block covers _____
cutaneous innervation to posterior thigh and all of the leg and foot below the knee,
EXCEPT medial strip supplied by saphenous n.
The saphenous nerve supplies sensation to ___
skin on the medial side of the leg and foot
Second order neurons describe transmission of pain signals from _____ to ____
dorsal horn of the spinal cord
contralateral spinothalamic tract to thalamus
TENS is a useful treatment of ______ and involves electrical stimulation of _____ to inhibit signaling of ________ fibers.
Myofascial pain syndrome
- acute and chronic
Large diameter A-beta cutaneous mechanoreceptors to inhibit signaling of A-delta and C pain fibers
Are the analgesic effects of TENS reversible?
Yes - with naloxone
- implies mu-receptor agonism, central and peripheral
______ involves osteoarthritic degeneration, causing axial back pain that may radiate to ipsilateral buttocks or thigh. Pain worsened with spinal hyperextension and lateral rotation. Achy in nature, not electrical. Not associated with numbness, weakness, or tingling.
Facet syndrome / Facet arthropathy
Cons of PCA vs On-request Opioid
PCA:
- More pruritus
- more respiratory depression if PCA + continuous
(True/False) application of TENS electrodes on the contralateral limb has shown successful analgesia
True
THe superior hypogastric plexus is found at ___
L5 anterior to the aortic bifurcation
The ________ block targets the sympathetic fibers that innervate the pelvic organs and is therefore effective in treating chronic pelvic pain
superior hypogastric block
in early complex regional pain syndrome (CRPS), _____ block may be indicated
Lumbar sympathetic block
-plexus: L2-L5
The suprascapular nerve is derived from _____ via the brachial plexus
C5-C6
Chronic shoulder pain d/t arthritis can be managed with _____ nerve bloc.
Suprascapular nerve block
Post-stroke pain, paresthesias, and allodynia are likely a result of _____
thalamic pain syndrome
- d/t latent brain plasticity after a thalamic injury
Inhibitory neurotransmitters
Glycine and y-aminobutyric acid (GABA)
Nociceptors consists of ___ and ___ fibers with cell bodies located in the trigeminal and dorsal root ganglia
A-delta
C fibers
Chronic opioid therapy has profound effects on adrenal and gonadal axes leading to which effects on hormones?
Increased
1. prolactin
Decreased
- testosterone
- Estrogen
- Cortisol
- LH
- FSH
What is coccydynia?
Chronic pain syndrome that occurs from traumatic and nontraumatic causes
- fractures
- child birth
- tumors
