Chronic progressive condition characterized by severe pain, swelling, and skin changes.
Subtypes
- Type 1 (AKA RSD) : not associated with nerve injury, but may be associated with other trauma –
- Type 2 (AKA causalgia): associated with nerve injury
Both types:
- spontaneous pain or allodynia not limited to single peripheral nerve distribution — disporportionate to inciting event.
- history of edema, blood flow abnormality, abnormal sweating.
- no better explanation exists.
Pathophysiology
- upregulation of NMDA receptors
- elevated glutamate levels
- immunogenic
- cytokine release
- neurogenic inflammation
- adrenoreceptor pathology
- sympathetic afferent coupling
- …etc.
Epidemiology
- 3:1 female predominance
- most common in 4th decade, but wide variation in age range affected.
- 2-5% of patients with a peripheral nerve injury
Symptoms
- at site of a previous injury (of varying severity)
- spread beyond site of original injury.
- most commonly burning pain
- also muscle spasms, local swelling, joint tenderness / stiffness, nail and skin changes.
- allodynia / hyperalgesia
- eventually disuse atrophy and stiffness.
Stages
- Type one is characterized by severe, burning pain at the site of the injury. Muscle spasm, joint stiffness, restricted mobility, rapid hair and nail growth, and vasospasm.
- Type two is characterized by more intense pain. Swelling spreads, hair growth diminishes, nails become cracked, brittle, grooved, and spotty, osteoporosis becomes severe and diffuse, joints thicken, and muscles atrophy.
- Type three is characterized by irreversible changes in the skin and bones, while the pain becomes constant and may involve the entire limb. There is marked muscle atrophy, severely limited mobility of the affected area, and flexor tendon contractions.
Diagnosis is primarily clinical, but adjuncts are:
- thermography
- sweat testing
- radiography – patchy osteoporosis; bone scan, bone densitometry
- electromyopgraphy (for type II)
- nerve blocks
Treatment
- PT/OT: desensitization, mobilization
- Medication: GABA agonists, steroids, antidepressants, NSAIDs
- nerve blocks
- neurostimulation
- sympathectomy
- ketamine
Filed under: orthopedic surgery
