Complex Regional Pain Syndrome

Key Features

Essentials of Diagnosis

• Rare disorder characterized by autonomic and vasomotor instability

• Intense, burning pain; often greatly worsened by minimal stimuli, such as light touch

General Considerations

• Formerly called reflex sympathetic dystrophy

• Most cases are preceded by direct physical trauma, often of relatively minor nature, to the soft tissues, bone, or nerve

• May occur after a knee injury or after arthroscopic knee surgery

• Any extremity can be involved, but the hand is most commonly affected and is associated with ipsilateral restriction of shoulder motion (shoulder-hand syndrome)

• The shoulder-hand variant sometimes complicates myocardial infarction or injuries to the neck or shoulder

• The posttraumatic variant is known as Sudeck atrophy

Clinical Findings

Symptoms and Signs

• No systemic symptoms

• Localized pain

• Swelling of involved extremity

• Disturbances of color and temperature in affected limb

• Dystrophic changes in overlying skin and nails

• Limited range of motion

• Findings are not limited to the distribution of a single peripheral nerve

Differential Diagnosis

• Other cervicobrachial pain syndromes

• Rheumatoid arthritis

• Thoracic outlet obstruction

• Systemic sclerosis (scleroderma)

Diagnosis

Imaging Studies

• Bone scans

  • Sensitive in the early phases

  • Show diffuse increased uptake in affected extremity

• Radiographs eventually reveal severe generalized osteopenia

Treatment

Medications

• Nortriptyline

  • Initial dose: 10 mg orally at bedtime

  • Increase gradually to 40–75 mg at bedtime

• Gabapentin, 300 mg three times daily orally

• For mild cases, NSAIDs (eg, naproxen 250–500 mg twice daily orally) can be effective

• For more severe cases associated with edema, prednisone, 30–60 mg/day orally for 2 weeks and then tapered over 2 weeks, can be effective

• Bisphosphonates, calcitonin, regional nerve blocks, and dorsal-column stimulation have been reported to be helpful

Therapeutic Procedures

• Patients with restricted shoulder motion may benefit from physical therapy for scapulohumeral periarthritis

• Regional nerve blocks and dorsal-column stimulation

Outcome

Prognosis

• Good with early treatment

Prevention

• Early mobilization after injury, surgery, or myocardial infarction

References