Complex Regional Pain Syndrome (CRPS)

Question 1

what are the 2 types of CRPS?

Answer 1

CRPS 1: complex disorder that may develop as a consequence of trauma affecting the limb(s) without an obvious nerve lesion

CRPS 2: aka “causalgia,” the same as CRPS, but with a well-defined peripheral nerve injury. May demonstrates neurological symptoms

Question 2

what are the characteristics of CRPS in children?

Answer 2

often no preceding traumatic event
occurs more often in LEs
osteoporosis is rare
more favorable prognosis than adults
bone scan results more inconsistent with decreased uptake when study is positive

Question 3

what are the 4 theories to describe CRPS?

Answer 3

1. aberrant neurogenic inflammation
2. vasomotor dysfunction
3. nociceptive sensitization
4. neuroplasticity central nervous system

Question 4

what is the mechanism for the “abberant neurogenic inflammation” theory in CRPS?

Answer 4

the release of neuropeptides in the periphery due to retrograde depolarization, producing vasodilation and protein extravasation

Question 5

what is the mechanism for the “vasomotor dysfunction” theory in CRPS?

Answer 5

inhibition of sympathetic vasoconstrictor neurons

Question 6

what is the mechanism for the “nociceptive sensitization” theory in CRPS?

Answer 6

excitation of peripheral nociceptors by cytokines, leading to amplification of signaling

Question 7

what is the mechanism for the “neuroplasticity of the central nervous system” theory in CRPS?

Answer 7

spinal and cerebral neurons become more responsive, may fire without input and lose inhibition capabilities

Question 8

what is hyperalgesia?

Answer 8

increased sensitivity to stimulation with a lower threshold to pain

Question 9

what is hypoesthesia?

Answer 9

decreased sensitivity to stimulation

Question 10

what is hyperpathia?

Answer 10

excessive reaction to stimuli that outlasts the initiating stimulus and spreads beyond normal dermatomal borders

Question 11

what is allodynia?

Answer 11

pain arising from a nonnoxious stimuli

Question 12

what is dysesthesia?

Answer 12

an unpleasant abnormal sensation

Question 13

what are sudomotor changes?

Answer 13

edema
hyperhydrosis
anhydrosis

Question 14

whare are trophic changes?

Answer 14

hair changes
loss of skin wrinkles
shiny skin
penciling of fingertips 2/2 palmar pad atrophy
nail changes

Question 15

what are vasomotor changes?

Answer 15

temperature asymmetry
skin color changes
vasoconstriction
vasodilation
vasomotor spasm
prolonged capillary refill

Question 16

what are sensory changes?

Answer 16

hyperesthesia
allodynia to light touch

Question 17

what are motor changes?

Answer 17

weakness
dystonia

Question 18

what are helpful tests for dianosing CRPS?

Answer 18

**Triple phase bone scan (TPBS)
radiographs to look for osteoporosis
isolated cold stress test
laser Doppler velocimetry

Question 19

what is a phentolamine test?

Answer 19

mixed 1-/alpha 2-adrenergic antagonist; blocks the sympathic receptors from receiving circulating norepinephrine and epinephrine; specific for SMP

Question 20

what is the QSART test for CRPS?

Answer 20

measurement o stimulate sweat output; greater and prolonged with a hyperfunctioning sympathetic nervous system

Question 21

what are the 3 criteria for diagnosis of CRPS?

Answer 21

1. an inciting noxious event or an immobilization
2. continuing pain, allodynia, or hyperalgesia to any inciting event
3. evidence at some point of edema, changes in skin blood flow, or abnormal sudomotor activity in the region of pain

Question 22

which patients respond best to a stellate ganglion block?

Answer 22

patients with SMP (sympathetically maintained pain) will respond to the blockade because the CNS is not involved. in patients with SIP (sympathetically independent pain), stellate ganglion blocks are often ineffective

Question 23

what are the required symtoms for a diagnosis of Fibromyalgia?

Answer 23

diagnosis is based on a constellation of symtpoms and exclusion of inflammatory and metabolic diseases. Pain is chronic (>3 mo), widespread, bilateral, and across all 4 quadrants. Tenderness to palpation of at least 11 of 18 defined tender points. Fatigue, disrupted sleep, headaches, and mood disorders are common.

Question 24

which drugs are helpful in the management of CRPS?

Answer 24

adrenergic compounds
calcium channel blockers
corticosteroids
bisphosphonates

Question 25

what percentage of patients with CRPS present with osteopenia or osteoporosis?

Answer 25

70-80%