CRPS

Definition

 

Chronic Regional Pain Syndrome

 

CRPS 1

 

Sympathetically mediated pain syndrome

- excessive or exaggerated response of extremity to injury, surgery or disease

 

Manifested by

- intense or unduly prolonged pain

- vasomotor disturbances

- trophic changes

- delayed functional recovery

 

CRPS 2

 

Following injury to nerve plexus or peripheral nerve

 

Historical Names

 

RSD (regional sympathetic dystrophy)

 

Sudeck's Atrophy 1900

- acute atrophy of bone associated CRPS

- associated with marked spotty osteoporosis

 

Aetiology

 

Usually preceded by trivial injury or surgery

 

Colles fracture

- most common

- 25 %

- associated with tight cast

 

Crush injury

 

Association with coronary artery disease

- like frozen shoulder

 

Shoulder-Hand Syndrome

- 10% cord or head injury

- i.e more common in stroke patients

- sustain injury to shoulder resulting in CRPS1 in ipsilateral hand

 

Pathology

 

Basis is excessive sympathetic efferent activity

- disturbance of centrally mediated autonomic regulation

 

Exact pathophysiology is unknown

- may involve all motor, sensory, sympathetic and parasympathetic fibres

- pathological changes are thought to occur in the spinal cord 

- abnormal connections form between motor / sensory / autonomic pathways

 

Injury

- often trivial

- some personalities predisposed

- anxious & hypersensitive

 

Theories

 

1. Feedback Theory

- abnormal state of activity in interneurones

- continous stimulation of sympathetic & motor efferents

 

2. Gate Control Theory

- disorder of inhibitory fine tuning

- cells in dorsal horn that modulate afferent transmission

 

3. Peripheral Cross Stimulation Theory

- peripheral Nerve trauma leads to formation of synapse between sensory afferent & motor efferents

- allows for direct cross stimulation & cycle formation

 

Clinical Features

 

Upper limb more common than lower limb

 

Cardinal features

- burning pain out of proportion to injury

- swelling

- stiffness

- vasomotor discoloration

- autonomic = oedema, vascular, sudomotor

- sensory allodynia / pain from non noxious stimuli to skin

 

CRPS HandCRPS Hand 2

 

Stages

 

Stage 1:  Acute 0-3/12

 

1.  Continued localised pain

2.  Sensory allodynia

3.  Motor - decreased ROM

4.  Autonomic - wet with excess sweating

5.  Skin changes - Swollen & warm

 

Xray - normal

Bone scan - positive

 

Stage II:  Dystrophic 3-6/12

 

1.  Proximal spread of pain

2.  Skin changes

- cool & dry

- mottled & dusky

- atrophic / shiny skin / decreased hair

3.  Oedema of limb

 

Xray - early osteoporosis on XR

 

Stage III: Atrophic > 6/12

 

1.  Intractable pain

2.  Atrophy of skin, muscles & bone

3.  Flexion contractures

4.  Diffuse osteoporosis on Xray

 

Prognosis

 

Mean duration of symptoms 32 months

 

Prevention

 

Zollinger et al Lancet 1990

- RCT of vitamin C 500mg v placebo post wrist fracture

- significant reduction in prevalence of CRPS 1

 

Management

 

Best results with early diagnosis and action

 

Physical Therapy

 

1.  Early active ROM / aggressive splinting

- avoid contractures

- passive and active ROM

 

2.  Oedema control

- pressure dressings / garments

 

3.  Desensitisation

- temperature / sensation

- cold water / hot water

- vibrations

 

Medications

 

NSAIDS

 

Amitriptyline

 

Gabapentin

 

van de Vusse e al BMC Neurol 2004

- RCT of gabapentin v placebo

- 2 three week treatments separated by 2 weeks

- some pain and sensory improvement

- not significant overall

 

Ketamine

 

Sigtermans et al Pain 2009

- RCT intravenous ketamine v placebo

- good pain relief

- minimal functional improvement

 

Sympathetic Interruption

 

Regional Sympathetic Blockade

- diagnoses and treatment

- almost always effective

- if not effective consider another cause

- effect usually temporary

- multiple procedures usually required

- if > 4 required, consider surgical sympathectomy

 

Options

- stellate ganglion blocks

- IV blocks / guanethidine / reserpine

- surgical sympathectomy

 

Stellate Ganglion Block

 

Technique

- 0.25% Marcaine

- can use Botox to lengthen the treatment effect

- anterior paratracheal approach

- at C6 level ~ cricoid cartilage

 

Results

 

Ackerman et al South Med J 2006

- stellate ganglion blocks with LA

- 40% success if symptoms < 6 weeks

- 36% success if duration 12 weeks

- 25% in group with symptoms averaging 35 weeks

 

Intravenous block / Bier's Block

 

Options

 

Guanethedine

- false transmitter

- taken up by sympathetic nerve endings

- displaces Noradrenaline

 

Reserpine

- depletes sympathetic nerve ending stores of Noradrenaline

- decreases storage vesicle reuptake

 

Results

 

Paraskevis et al Clin Rheumatol 2006

- bier blocks of guanethedine and lidocaine

- multiple treatments required

- complete pain relief and return to function in all 17 patients

 

Surgical Sympathectomy

 

Indication

- good but temporary relief from 4 blocks

 

Amputation

 

Contra-indicated

- poor results with stump RSD