Complex Regional Pain Syndrome
- Also known as
- RSD Reflex Sympathetic Dystrophy
- Causalgia
| CRPS I = RSD | CRPS II = Causalgia |
|---|---|
| Initiating noxious event or cause for immobilisation | Initiating injury to nerve |
| Continuing pain or hyperalgesia disproportionate to initiating event | Continuing pain, hyperalgesia or allodynia following nerve injury but not necessarily limited to distribution of the nerve |
| Evidence of oedema, cutaneous blood flow changes or abnormal sudomotor activity | Evidence of oedema, cutaneous blood flow changes or abnormal sudomotor activity |
| Excluded by diagnosis that would account for degree of pain and dysfunction | Excluded by diagnosis that would account for degree of pain and dysfunction |
Types
- Type 1: RSD
- 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
- Type 2: Causalgia
- Constant burning pain following injury to nerve plexus or peripheral nerve
- Sudeck's Atrophy
- Acute atrophy of bone associated with local injury
- Associated with pain, swelling & loss of function
- Pain in extremity following injury
- Associated with marked spotty osteoporosis
Aetiology
- Usually preceded by injury
- more common after trivial injury rather than major
- can be either sympathetically mediated or sympathetically independent
- exact pathophysiology is unknown
- may involve all motor, sensory, sympathetic and parasympathetic fibres
- pathological changes are thought to occur in the spinal cord where abnormal connections form between motor / sensory / autonomic pathways
- Most common Colles fracture
- 25 %
- 60 % with tight cast
- Seen with crush injury
- May be trivial & forgotten
- May occur with Coronary Artery Disease
- Like Frozen Shoulder
- Shoulder-Hand Syndrome
- Associated with partial or complete nerve injury
- 10% cord or head injury
Pathology
- Three factors
- Injury - Often trivial
- Diathesis
- Some personalities predisposed
- Anxious & hypersensitive
- Disturbance of centrally mediated autonomic regulation
- Basis is excessive Sympathetic Efferent Activity
- Numerous Theories
- Feedback Theory
- Cycle of 3 factors
- Chronic irritation of Peripheral Nerves 2° -> Trauma or soft tissue damage
- Abnormal state of activity in interneurones
- Continued stimulation of sympathetic & motor efferents
- Cycle of 3 factors
- Gate Control Theory
- Disorder of inhibitory fine tuning
- Cells in Dorsal Horn that modulate afferent transmission
- Small stimulatory "C" & large inhibitory "A" fibres
- Cortical feedback
- Selective activation of stimulated fibres opens gate
- Peripheral X Stimulation Theory
- Peripheral Nerve trauma leads to formation of synapse between sensory afferent & motor efferents
- Allows for direct cross stimulation & cycle formation
- Feedback Theory
Clinical Features
- Mean duration of symptoms 32/12
- 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
- Motor = spasm
- UL commoner than LL
Stages
| Stage 1 | Stage 2 | Stage 3 | |
|---|---|---|---|
| Acute | Dystrophic | Atrophic | |
| Time | 0-3/12 | 3-6/12 | > 6/12 |
| Symptoms |
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| Signs |
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| Investigations |
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XR: Early osteoporosis |
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Prognosis
- sympathetically mediated CRPS has better prognosis than sympathetically independent CRPS
- Mean duration of symptoms 32m
Management
- Early = best results
- Late = poor outcome
- functional use of entire limb through supervised physiotherapy
- diagnostic or therapeutic neural block
- includes stellate ganglion; brachial plexus & IV guanethidine block
- anti-neuropathic pain medication
- Physical - stress loading
- Early active ROM
- Aggressive splinting
- Avoid contractures
- Deep friction massage
- May enhance "A" fibres
- TENS - May stimulate "A" fibres
- Avoid - Passive ROM
- Temperature extremes
- Sympathetic Interruption
- Regional Sympathetic Blockade
- Almost always effective
- If not effective consider another cause
- Effect usually temperature
- Multiple procedures usually required
- If > 4 required, consider surgical sympathectomy
Stellate Ganglion Block
- Technique
- 0.25% Marcaine
- Anterior paratracheal approach
- At C6 Level ~ Cricoid cartilage
- Success manifested by
- Profound Horner's
- Rapid onset of pain relief
- Cool, dry hand
- Followed by gentle physiotherapy
Intravenous block
- Technique
- Bier's block
- Infusion of Guanethedine or Reserpine
- Basis
- Guanethedine is false transmitte
- Taken up by sympathetic nerve endings & displaces Noradrenaline
- Reserpine depletes sympathetic nerve ending stores of Noradrenaline by decreased storage vesicle reuptake
- Guanethedine is false transmitte
Surgical Sympathectomy
- Indicated if partial /temperature relief from 4 blocks
Corticosteroids
- Short high doses used
- No controlled trials
- MOA unclear
- Significant Side Effects
Acupuncture
- Effective in 90%
- ? "Closes the gate"
Pharmacologic
- Amitriptyline
- Nifedipine - Peripheral vasodilation
- Gabapentin
- Oxycodone
Therapeutic Trial |
||
|---|---|---|
Amitriptylline |
Up to 50mg nocte |
Inc every 5 days |
Gabapentin |
Up to 600mg tds |
Slow introduction |
Mexiletine |
Up to 100mg tds |
Slow introduction |
Oxycodone |
5mg prn |
Convert to SR |
Dorsal column stimulator
Intraspinal opioid
Amputation
- Phantom Limb Pain
- 50-75% incidence
- early onset
- diminishes with time
- distally located
- lower > upper
- Mechanisms
- peripheral
- neuroma
- spontaneous activity of peripheral nerve
- spinal
- disinhibition of dorsal horn neurons
- expansion of receptive fields
- supraspinal
- cortical reorganisation
- peripheral
- Treatment
- Peri-operative regional anaesthesia
- Anti-neuropathic pain medications
- Revision of stump neuroma
- Treatment of stump infection or pressure areas
- Revision of prosthesis
Webpage Last Modified: 14 October, 2011
