Sympathetic Pain Flashcards
pain: definition
unpleasant sensory + emotional experience associated with actual or potential tissue damage
biology of pain (purpose)
protective mechanism to prevent tissue injury and permit recovery from injury
nociception: def
physiological processing of tissue damaging information
hyperalgesia: def
heightened pain, when damaged tissue is exposed to noxious stimulus
analgesia: def? not the same as?
loss of pain. not the same as anaesthesia = loss of sensation
allodynia: def?
pain arising from gentle touch, painful response to a stimulus that isn’t normally painful
musckuloskeletal/mild pain: what are the two pains, main sensation, and fiber?
first pain = pricking pain, a-delta fibers. second pain = burning, more diffuse pain via C-fibers
first pain: is what?
initial response to tissue damage sensed by free nerve endings, transmitted by sensory a-delta fibers
secondary pain: is what? what transmitters? (4)
ongoing pain, by release of bradykinin, histamine, acid metabolites, prostaglandins at site of lesion
deep pain: aka? treatment? type of pain/feeling?
nociceptive pain. treated with opioids. deep aching pain, felt as deep to the body surface, poorly localized.
deep pain: causes?
initiated by major trauma like post operative pain, injury, childbirth. can also be pain due to disease like cancer, heart attack
neuropathic pain: results from? examples? (5)
results from nerve injury, or herpes zoster infections. phantom limb pain, causalgia, trigeminal neuralgia, diabetic neuropathy, HIV-AIDS neuropathy.
neuropathic pain: what? onset? characterized by?
chronic, bad pain. slow onset that outlasts original injury. allodynia, hyperalgesia, causalgia, spontaneous stimulus independent pain
neuropathic pain: response to medication?
responds poorly to opioids. treat with antidepressants, cannabinoids, or anticonvulsants like pregabalin or gabapentin
CRPS: stands for? what is it?
complex regional pain syndrome: chronic neuropathic pain associated with altered sympathetic outflow; most painful chronic condition
CRPS: initiated by? what body parts affected? 3 characteristics?
initiated by tissue injury. affected part usually hands or feet. hot or cold from altered vasomotor outflow, damp from increased sudomotor activity, piloerection
two types of CRPS?
type I (reflex sympathetic dystrophy or sudeck’s atrophy) - no demonstrable nerve lesions. type II (causalgia) - evidence of obvious nerve damage
diagnosis of CRPS: need to distinguish from? goes away with?
from other chronic pain syndromes like fibromyalgia, MS. goes away with sympathetic blockade like phentolamine (alpha blocker)
diagnosis of CRPS: process?
establish baseline pain. give phentolamine or placebo. blockade of sympathetic nerve terminals confirmed by measuring skin temperature going up. measure pain scores
diagnosis of CRPS: why also give beta blocker/propanolol?
phentoalmine/alpha blocker decreases blood pressure so baroreceptor reflex increases HR. propanolol blocks this effect on the heart so pt doesn’t know if they received placebo or treatment
treatment of CRPS: what is ineffective? injection?
opioid/NSAIDs ineffective. local anesthetic sympathetic blocks into stellate or L2-L4 ganglia = lasting pain relief
treatment of CRPS: topical? oral? surgical?
topical clonidine (alpha 2 agonist to restrict regional sympathetic outflow. oral sympatholytic agents like prazosin - too much hypotension. surgical sympathectomy
CRPS: what works best for treatment? but?
pregabalin/gabapentin (anticonvulsants) work best for all neuropathic pains, but only effective 30% of time
