Flashcards in Chronic Pain Deck (34)
Protopathic pain is conducted by what nerve fibers?
A-delta and C nerve fibers (noxious)
What is epicritic sensation?
Non-noxious: touch, pressure, proprioception, temperature
What is a rhizotomy?
Transection of dorsal nerve root of the spinal cord
Why do you have continued pain after rhizotomy?
1. Some C fibers enter the ventral nerve root
2. 1st order neurons can travel up or down 3 segments in Lissaur's tract
Where do opioids primarily act upon in the pain pathway?
Dorsal horn of the spinal cord
What are wide dynamic range neurons responsible for?
Central sensitization of pain secondary to "wind up" (repeated stimulation leading to huge pain transduction)
What nerve fibers carry fast pain?
A-delta fibers (myelinated)
What nerve fibers carry delayed pain?
How do NSAIDs and aspirin help with pain?
Decreases prostaglandin formation which is responsible for nociceptor sensitization
How does peripheral sensitization occur?
Chemical mediators (bradykinin, prostaglandins, substance P, etc.), heat, frequency of stimuli
How does central sensitization occur?
Wind up (repeated stimulation leading to a huge increase in pain transduction) and neurochemical mediators (CGRP, substance P, etc.)
Mechanism of action for tramadol?
Weak mu-receptor agonist, increased serotonin release, decreased NE reuptake, NMDA receptor antagonist, capsaicin (VR1) receptor agonist
What treatment option can prevent the pain syndrome of post-herpetic neuralgia?
Epidural anesthesia (sympathectomy) since post-herpetic neuralgia has a sympathetic component
CRPS I vs II
I: Reflex sympathetic dystrophy
When would you use an EMG for CRPS?
To differentiate between CRPS I and II (abnormal in II)
Progression of CRPS can be evidenced by: increased opioid use, warm/red extremities, osteoporosis, sweat testing, EMG
Osteoporosis (stage 2 of CRPS)
Most effective treatment for early CRPS?
Stellate ganglion blocks (~3-12 injections)
Which gender is more prone to developing CRPS?
Treatment for phantom limb pain?
Anticonvulsants, TCAs, Alpha-2 agonists, NMDA antagonists, opioids
What type of anesthesia should be avoided in patients with phantom limb pain?
Definition of dysasthesia
Unpleasant sensation with or without a stimulus
Definition of anesthesia dolorosa
Pain in an area that lacks sensation
Definition of neuralgia
Pain in the distribution of nerves
Definition of allodynia
Perception of non-noxious (epicritic) sensation as pain
How do transcutaneous electrical nerve stimulation (TENS) work?
Stimulating large afferent epicritic fibers (i.e. rubbing a painful area to help "distract" from the pain)
Which is an unexpected complication from a stellate ganglion block: hoarseness, nasal stuffiness, ptosis, miosis, anhidrosis
Hoarseness: blockage of the recurrent laryngeal nerve
Stellate ganglion block is done by locating which transverse process?
Chassiaignac's tubercle of C6
Celiac plexus is found at which vertebral level?
Common side effect of a successful celiac plexus block?
Hypovolemia from the upper abdominal sympathectomy (decreased SVR and increased venous pooling)
What is the advantage of using an intrathecal pump for opioids vs. PO?
Decreased doses are used so less likely to have side effects (still have tolerance and withdrawal effects)
Patient with disk herniation and radiculopathy had lumbar epidural steroid injection done with minimal relief, what is the best next step?
Repeat LESI with same dose of steroid; can take up to 3 injections to be successful
Interventional treatment for facet syndrome?
Medial branch steroid injection (level above and at the level)
Lower back pain, worse with sitting and walking down stairs with normal ABIs