Lecture 9 (2/3) Flashcards
what are Causes of Chronic Neuropathic Pain?
nerve trauma, nerve compression, iatrogenic injury, infections, inflammation of nerve, toxins, radiation
what is iatrogenic?
caused by the medical treatment itself
what is carpal tunnel syndrome?
when nerves get caught in the openings, they are being pressed down
- can also be from tumours
what is hereditary neuropathy?
genes that go awry, leading to nerve disfunction
difference between neuropathic and inflammatory pain
- neuropathic: dynamic
- inflammatory: not dynamic
sensory deficits are:
neuropathic
Allodynia and hyperalgesia is more common in:
neuropathic pain
what is distal radiation?
pain moving away from center to sides
are paroxysms more common in neuropathic or nociceptive pain?
neuropathic
how does PDN (painful diabetic neuropathy) injure tissue?
- Damage to blood vessels
- Nerves get damaged
- Numb bc of nerve damage
- If you don’t have pain, you will have numbness / ppl with pain: numb and pain
- Why a foot? Glove and stocking distribution
___% of chickenpox people experience shingles at some pt in life
50%
- 20% of those people can develop PHN
what is post herpetic neuralgia?
- Virus goes dormant in one of your DRG until sometime in your 60-70s
- You’ll get a rash in the dermatome where the virus went dormant (shingles)
- Only called PHN if the pain doesn’t go away after rash goes away
trauma only accounts for __% of amputations
8%
what are the top 2 causes of amputations
1 cause of amputations: type 2 diabetes
#2 cause: PAD (peripheral artery disease)
which part of the body is more commonly amputated?
More common upper limbs to be amputated (more severe and frequent)
what are phantom limb symptoms?
- pain
- itch, vibration, temperature
- movement
- size, shape, position
rings, etc. - referred phantom sensation
what is telescoping in PLP?
over time, they feel like their phantom limb is retracting into their body
- Sometimes they feel like they can’t open a phantom hand (it’s retracted)
phantom limb pain might be because of changes in:
the brain OR in the periphery (and brain is changing bc of changes in periphery)
- We don’t have an answer for that for pain in general either
what is the central hypothesis for PLP?
If people have phantom limb pain, area of cortex responsible for amputated limb can take over function of other body parts
- Suggest if you have PLP, something has gone wrong
explain evidence for peripheral hypothesis in PLP
- Lidocaine blocks are very effective – if you do on spinal nerve of DRG, PLP is always gone (almost 100%)
- If you do it near the stump, it’s still pretty effective (50%)
- mirror box therapy
what is mirror box therapy?
- brain got fooled and phantom limb pain went away
- At week 4, they crossed over the other group to mirror therapy and it worked
- Cheap, no side effects, BUT
- Fails to replicate
what is Complex regional pain syndrome (CRPS)?
a disabling condition characterized by burning pain, increased sensitivity to tactile stimuli, and sensations of pain in response to normally non-painful stimuli
what are the key neurological processes involved in CRPS?
Wind-up (the increased sensation of pain with time) and central nervous system (CNS) sensitization
what receptor has significant involvement in CRPS sensitization process?
NMDA receptors + CNS glutamate levels
- also evidence of NMDA receptors in peripheral nerves
what is CRPS type 2?
classic traumatic neuropathic pain (single peripheral nerve damage with burning, allodynia hyperalgesia)
- Follows a discrete nerve distribution
- Responds well to nerve blocks
- Has mechanical allodynia
what is CRPS type 1?
not clearly neuropathic, inflammatory, or neuropathic (own category)
- Clear evidence that something is wrong bc they have swelling, redness, change in skin temp (burning hot or ice cold), hair falls out, thickened nails, crazy sweating or none (changes in autonomic functioning in addition to the pain)
- Doesn’t respond well to nerve blocks, but might respond well to sympathetic blocks
- Used to be called reflex sympathetic dystrophy (RSD)
what causes CRPS?
- Inflammatory reactions
- Peripheral sensitization
- Central sensitization
- Cortical Plasticity
- Sympathetic processes
- Psychological Factor
- Genetic Predisposition
