reflex sympathetic dystrophy

definition

Reflex sympathetic dystrophy

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

· manifested by

· intense or unduly prolonged pain

· vasomotor disturbances

· delayed functional recovery

· trophic changes

Causalgia

· constant burning pain following injury to nerve plexus or peripheral nerve

Sudek’s atrophy

· Sudek 1900

· acute atrophy of bone associated with local injury

· associated with pain, swelling and loss of function

· pain in extremity following injury

· associated with marked spotty osteoporosis

aetiology

· usually preceded by injury

· most commonly Colles fracture

· seen with crush injury

· may be trivial and forgotten

· may occur with coronary artery disease

· shoulder-hand syndrome

pathogenesis

· three factors

1. injury

· often trivial

2. diathesis

· certain personalities predisposed

· anxious, hypersensitive

3. disturbance of centrally mediated autonomic regulation

· basis is excessive sympathetic efferent activity

· numerous theories

Feedback theory

· cycle of 3 factors

· chronic irritation of peripheral sensory nerve secondary to trauma and soft tissue damage

· abnormal state of activity in interneurones

· continuous stimulation of sympathetic and motor efferents

Gate control theory

· disorder of inhibitory fine-tuning mechanism

· cells in dorsal horn that modulate afferent transmission

· small stimulatory (C) and large inhibitory (A) fibres

· cortical feedback

· selective activation of stimulatory fibres opens gate

Peripheral theory

· trauma of peripheral nerves leads to formation of synapse between sensory afferents and motor efferents

· allows for direct cross stimulation and cycle formation

clinical features

Cardinal features

· burning pain out of proportion to injury

· swelling

· stiffness

· discoloration

Stages

Acute

· 0-3 mths

· localised pain

· continuous

· aggravated by stress

· skin changes

· hyperaesthetic and tender (allodynia)

· swollen and warm

· wet with excess swelling

· joints have decreased ROM

· x-ray normal

· bone scan positive

Dystrophic

· 3-6 mths

· proximal spread of pain

· oedema of limb

· skin

· cool and dry

· mottled and dusky

· atrophic with shininess and decreased hair

· early osteoporosis on x-ray

Atrophic

· 6 mths +

· intractable pain

· atrophy of skin, muscles and bone

· flexion contractures

· narrowing of joint space

· diffuse osteoporosis on x-ray

treatment

Physical

· early active range of motion

· aggressive

· splinting

· avoid contractures

· deep friction massage

· may enhance A fibres

· TENS

· may stimulate A fibres

· avoid

· passive range of motion

· extremes of temperature

Sympathetic interruption

Regional sympathetic blockade

· diagnostic and therapeutic

· almost always effective

· if not effective consider another cause

· effect usually temporary

· multiple procedures usually required

· if more than 4 required, consider surgical sympathectomy

Stellate ganglion block

· technique

· 0.25% Marcaine

· anterior paratracheal approach

· at level of C6 (cricoid cartilage)

· success manifested by

· profound Horner’s syndrome

· 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 transmitter - taken up by sympathetic nerve endings and displacing noradrenaline

· reserpine reduces storage vesicle reuptake of catecholamines - depletes sympathetic nerve ending stores of noradrenaline

Surgical sympathectomy

· indication

· partial or temporary relief from 4 blocks

Corticosteroids

· short high doses used

· no controlled trials

· mechanism of action unclear

· significant side-effects

Acupuncture

· effective in 90%

· may close the gate