Complex Regional Pain Syndrome -

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

Complex Regional Pain Syndrome

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

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

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

	Stage 1	Stage 2	Stage 3
	Acute	Dystrophic	Atrophic
Time	0-3/12	3-6/12	> 6/12
Symptoms	Continued localised pain Aggravated by stress	Proximal spread of pain	Intractable pain
Signs	Skin changes Swollen & warm sensory – allodynia autonomic – wet with excess swelling motor – joints have decreased ROM	Skin changes Cool & dry Mottled & dusky Atrophic with shininess & decreased hair Oedema of limb	Atrophy of skin, muscles & bone Flexion contractures
Investigations	XR: normal Bone scan +ve with Periarticular accentuation on delayed scan Highly specific Not predictive	XR: Early osteoporosis	XR: Narrow joint space Diffuse osteoporosis

Stages of CRPS

sympathetically mediated CRPS has better prognosis than sympathetically independent CRPS
Mean duration of symptoms 32m

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

Technique
- Bier’s block
- Infusion of Guanethedine or Reserpine
Basis
1. Guanethedine is false transmitte
  - Taken up by sympathetic nerve endings & displaces Noradrenaline
2. Reserpine depletes sympathetic nerve ending stores of Noradrenaline by decreased storage vesicle reuptake

Dorsal column stimulator

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
- Treatment
  - Peri-operative regional anaesthesia
  - Anti-neuropathic pain medications
  - Revision of stump neuroma
  - Treatment of stump infection or pressure areas
  - Revision of prosthesis