Chapter 192 - Complex regional pain syndrome Flashcards

1
Q

Complex regional pain syndrome other historic names

A

1) posttraumatic pain syndrome
2) causalgia
3) reflex sympathetic dystrophy

and many more

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2
Q

Epidemiology of CRPS

incidence
gender ratio
age

A

1-12% with peripheral nerve injury
female 2-4x more
higher in elderly

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3
Q

CRPS causes three types

A

1) traumatic
2) nontraumatic
3) idiopathic

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4
Q

Traumatic causes of CRPS

A

1) fracture
2) dislocation
3) sprains
4) crush injury
5) burns
6) iatrogenic injury

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5
Q

Most commonly involved never in traumatic causes of CRPS

A

1) median nerve

2) sciatic nerve

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6
Q

Nontraumatic causes of CRPS

A

1) prolonged bed rest
2) neoplasm
3) metabolic bone disease
4) DVT
5) MI (5-20% get CRPS)
6) CVA

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7
Q

Shoulder-hand syndrome

A

chronic pain of UE secondary to MI

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8
Q

Sudeck atrophy

A

post-traumatic reflex dystrophy with bone involvement on XRAY

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9
Q

Three components of CRPS

A

Complex: dynamic and variable presentation
- autonomic, cutaneous, motor, inflammatory, dystrophic changes

Regional: distribution of symptoms beyond area of original region

Pain: pain out of proportion
- burning, thermo, allodynia

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10
Q

Types of CRPS

A

TYPE 1 = reflex sympathetic dystrophy

TYPE 2 = causalgia

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11
Q

Diagnostic criteria for CRPS TYPE 1

A

1) history of inciting event
2) spontaneous pain, hyperalgesia, allodynia beyond the territory of single peripheral nerve
3) disproportionate to initial event
4) edema, blood flow abnormality and abnormal sudomotor activity since initial event
5) absence of other conditions

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12
Q

Diagnostic criteria for CRPS TYPE 2

A

1) history of nerve injury
2) spontaneous allodynia or pain not limited to region of injury
3) edema, temperature and skin blood flow abnormality, abnormal sudomotor or motor dysfunction in region of pain since original nerve injury
4) absence of other conditions

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13
Q

CRPS NOS

A

not otherwise specified

subtype that partially meet current criteria but previous criteria said CRPS

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14
Q

Theories of CRPS pathogenesis

A

1) exaggerated local inflammatory response (neurogenic inflammation)
- elevated inflammatory mediators
- steroids help treat symptoms

2) sympathetically mediated syndrome
- sympathectomy may help short term but no long term effect

3) ischemia reperfusion injury
- vasoconstriction from inflammation and resultant vasodilation pain
- tadalafil helps with pain

4) central sensitization theory
- NMDA receptor caused pain
- ketamine (NMDA antagonist) helps

5) nerve damage
- amputated limbs show small fiber loss in CRPS

6) autoimmune
- antineuronal autoantibodies in 30-90% of CRPS
- IVIG helps with pain

7) cortical reorganization theory
- altered sensory representation of affected limb
- computer-based graded motor imagery helps
- mirror therapy helps

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15
Q

Trophic changes in CRPS

A
nail atrophy/hypertrophy
hair growth cahnges
skin atrophic
motor dysfunction
loss of ROM
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16
Q

Budapest consensus criteria on CRPS

A

1) pain disproportionate to event
2) have > 1 symptom of the following:
a) vasomotor: temperature or color asymmetry
b) sensory: hyperesthesia or allodynia
c) motor/trophic: decrease ROM, weakness, trophic changes
d) sudomotor/edema: sweating, edema
3) have > 2 signs of the same 4 domains
4) no other diagnosis

17
Q

Adjunctive tests for CRPS

A

1) pulse oximetry
2) nerve conduction studies
3) neuroinflmmatory mediators: substance P, bradykinin, CGRP

CRP, ESR, WBC should not be elevated

4) bone scan - non specific
5) MRI - non specific

18
Q

Temperature rise with sympathetic blockade

19
Q

CRPS pain relief with sympathetic blockade (immediate)

A

75-100%

less is non-specific

20
Q

Sympathetic blockade agents

A

1) iv alpha blocking phentolamine
2) iv bretylium
3) Bier blockade
4) spinal block
5) epidural
6) local anesthetic of paravertebral lumbar sympathetic chain (lidocaine or bupivacaine)

21
Q

First line treatment for CRPS

A

Physiotherapy

22
Q

Goals of physiotherapy

A

1) mobilization, swelling control, isometric strengthening
2) desensitization of affected region
3) stress loading, isotonic strengthening, ROM, postural normalization and aerobic doncitioning
4) vocational rehabilitation

23
Q

Adjunctive therapy to physiotherapy

A

1) mirror visual feedback
2) pain exposure physical therapy
3) transcutaneous electrical nerve stimulation
4) acupuncture and electroacupuncture

24
Q

Pharmacological therapy classes for CRPS

A

1) opioid: inhibit central nociception (mu receptors)
2) tricyclic antidepressants: inhibit reuptake monoaminergic transmitters
3) GABA agonist (gabapentin/neurontin)
4) alpha-adrenergic blocker: phentolamine, phenoxybenzamine, prazosin
5) beta blocker: propranolol
6) CCB: muscle relaxation increase blood flow
7) Bisphosphonate: inhibit osteopenic activity
8) NSAID
9) steroids

25
Sympathetic blockade in CRPS key points
1) temporary response 2) diagnostic 3) can reverse process if done in first 6 months 4) reduce pain score and depression in long run 5) no effect on long term quality of life
26
Epidural and intrathecal drug therapy in CRPS
effective but expensive and may require hospitalization
27
Drucker's three stages of CRPS
Stage 1: 0-3 months Stage 2: 3-6 months Stage 3: after 6 months
28
Surgical sympathectomy pain relief in patients that benefited from sympathetic blockade with local anesthetic
90%
29
Level of ganglionectomy
L2 + L3 +/- L4
30
Problem with bilateral high ganglionectomy (L1)
Ejaculatory disturbances
31
Chemical sympathectomy
L2, L3, L4 vertebrae injection of 3 ml of 6.5-7% phenol in water or 3ml of absolute alcohol
32
Open sympathectomy steps
flank incision split external, internal obliques and transversus abdominus Stay retroperitoneal Identify lumbar sympathetic chain behind IVC or aorta
33
Pain relief after sympathectomy
94%
34
Complications of sympathectomy
1) injury to genitofemoral nerve, ureter, lumbar vein, aorta, IVC 2) neuralgia 50% (ache in anterolateral thigh) - resolves 12 weeks later 3) retrograde ejaculation 25-50% if L1 sympathectomy bilateral
35
Treatment guidelines for CRPS TYPE 1 by stages
Stage 1: physiotherapy +/- TENS; sympathectic blockade, steroid Stage 2: surgical sympathectomy considered as well Stage 3: neuromodulation, maniputation of joint under anesthesia, antidepressant, vocational guidance