Sympathetic Pain

Question 1

pain: definition

Answer 1

unpleasant sensory + emotional experience associated with actual or potential tissue damage

Question 2

biology of pain (purpose)

Answer 2

protective mechanism to prevent tissue injury and permit recovery from injury

Question 3

nociception: def

Answer 3

physiological processing of tissue damaging information

Question 4

hyperalgesia: def

Answer 4

heightened pain, when damaged tissue is exposed to noxious stimulus

Question 5

analgesia: def? not the same as?

Answer 5

loss of pain. not the same as anaesthesia = loss of sensation

Question 6

allodynia: def?

Answer 6

pain arising from gentle touch, painful response to a stimulus that isn’t normally painful

Question 7

musckuloskeletal/mild pain: what are the two pains, main sensation, and fiber?

Answer 7

first pain = pricking pain, a-delta fibers. second pain = burning, more diffuse pain via C-fibers

Question 8

first pain: is what?

Answer 8

initial response to tissue damage sensed by free nerve endings, transmitted by sensory a-delta fibers

Question 9

secondary pain: is what? what transmitters? (4)

Answer 9

ongoing pain, by release of bradykinin, histamine, acid metabolites, prostaglandins at site of lesion

Question 10

deep pain: aka? treatment? type of pain/feeling?

Answer 10

nociceptive pain. treated with opioids. deep aching pain, felt as deep to the body surface, poorly localized.

Question 11

deep pain: causes?

Answer 11

initiated by major trauma like post operative pain, injury, childbirth. can also be pain due to disease like cancer, heart attack

Question 12

neuropathic pain: results from? examples? (5)

Answer 12

results from nerve injury, or herpes zoster infections. phantom limb pain, causalgia, trigeminal neuralgia, diabetic neuropathy, HIV-AIDS neuropathy.

Question 13

neuropathic pain: what? onset? characterized by?

Answer 13

chronic, bad pain. slow onset that outlasts original injury. allodynia, hyperalgesia, causalgia, spontaneous stimulus independent pain

Question 14

neuropathic pain: response to medication?

Answer 14

responds poorly to opioids. treat with antidepressants, cannabinoids, or anticonvulsants like pregabalin or gabapentin

Question 15

CRPS: stands for? what is it?

Answer 15

complex regional pain syndrome: chronic neuropathic pain associated with altered sympathetic outflow; most painful chronic condition

Question 16

CRPS: initiated by? what body parts affected? 3 characteristics?

Answer 16

initiated by tissue injury. affected part usually hands or feet. hot or cold from altered vasomotor outflow, damp from increased sudomotor activity, piloerection

Question 17

two types of CRPS?

Answer 17

type I (reflex sympathetic dystrophy or sudeck’s atrophy) - no demonstrable nerve lesions. type II (causalgia) - evidence of obvious nerve damage

Question 18

diagnosis of CRPS: need to distinguish from? goes away with?

Answer 18

from other chronic pain syndromes like fibromyalgia, MS. goes away with sympathetic blockade like phentolamine (alpha blocker)

Question 19

diagnosis of CRPS: process?

Answer 19

establish baseline pain. give phentolamine or placebo. blockade of sympathetic nerve terminals confirmed by measuring skin temperature going up. measure pain scores

Question 20

diagnosis of CRPS: why also give beta blocker/propanolol?

Answer 20

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

Question 21

treatment of CRPS: what is ineffective? injection?

Answer 21

opioid/NSAIDs ineffective. local anesthetic sympathetic blocks into stellate or L2-L4 ganglia = lasting pain relief

Question 22

treatment of CRPS: topical? oral? surgical?

Answer 22

topical clonidine (alpha 2 agonist to restrict regional sympathetic outflow. oral sympatholytic agents like prazosin - too much hypotension. surgical sympathectomy

Question 23

CRPS: what works best for treatment? but?

Answer 23

pregabalin/gabapentin (anticonvulsants) work best for all neuropathic pains, but only effective 30% of time