4 - Chronic Pain Flashcards
What is a phenotypic switch?
Although acute noxious stimuli are transmitted to the spinal cord via Aδ and C fibers, the presence of allodynia is thought to be mediated by the activation of large-diameter Aβ fibers
AB fibers develop the ability to secrete substance P
What causes radicular spinal pathology?
Facet pathology?
mechanical nerve root compression by a herniated disc
degenerative changes to the joints (like arthritis)
What is the treatment for radiculopathy?
Often ESI
What is the treatment for facet pain?
Radiofrequency rhizotomy of the medial branches
Which nerves are most commonly effected by herpetic neuralgia?
Cervical
Thoracic
Trigeminal
What are the two metabolites of morphine?
Morphine - 6 - gluconuride (analgesic)
Morphine - 3 - gluconuride (harmful)
What is NNT?
Numbers Needed to Treat
Why should oxycodone not be taken with alcohol?
Increases its plasma concentration by 300%
What are the weak opiods?
codeine
tramadol
hydrocodone
tapentadol
For what age group is codeine not effective?
Children under 12 lack the enzymes to convert prodrugs to morphine
Get all the side effects but no analgesia
Why are anticonvulsants useful in treating chronic pain?
Block membrane activity (usually via sodium channel blocking)
How long does it take for lidocaine patches to be effective?
A couple of days
What is chronic pain?
Persistent pain with distinct periods of uninterrupted pain for 3 months
Increases in substance P and substance P receptors is specifically related to what kind of pain?
Inflammatory
What are three big differences between inflammatory and neuropathic pain
- Inflammatory pain gets better when inflammation decreases. Neuropathic pain is persistent, even when tissue healing is evident.
- neuropathic pain causes allodynia, inflammatory does not
- neuropathic pain is not adequately managed with NSAIDs
What is CPSP?
Chronic Postsurgical Pain
persistent pain more than 2 months postop that can’t be explained by other causes