How should I diagnose and initially manage suspected Complex Regional Pain Syndrome in a patient with severe disproportionate limb pain, swelling, color or temperature changes, and motor or trophic abnormalities after trauma or immobilization?

Complex Regional Pain Syndrome: Diagnosis and Initial Management

Diagnosis

Complex Regional Pain Syndrome (CRPS) is diagnosed clinically based on the presence of continuing pain that is disproportionate to the inciting event, combined with sensory, vasomotor, sudomotor/edema, and motor/trophic abnormalities. 1

Clinical Diagnostic Criteria

The diagnosis requires 2, 1:

• Continuing pain disproportionate to any inciting event (this is the cardinal feature) 2, 1

• At least one symptom in three of four categories:

  • Sensory: hyperalgesia, allodynia 1
  • Vasomotor: temperature asymmetry, skin color changes 1
  • Sudomotor/edema: edema, sweating changes or asymmetry 1
  • Motor/trophic: decreased range of motion, motor dysfunction (weakness, tremor, dystonia), trophic changes (hair, nail, skin) 1

• At least one sign at time of evaluation in two or more categories:

  • Sensory: hyperalgesia to pinprick, allodynia to light touch 1
  • Vasomotor: temperature asymmetry >1°C, skin color changes or asymmetry 1, 3
  • Sudomotor/edema: edema, sweating changes or asymmetry 1
  • Motor/trophic: decreased range of motion, motor dysfunction, trophic changes 1

Critical Diagnostic Pitfalls

Temperature differences >1°C between limbs, while considered diagnostic, are actually less common than previously assumed and should not be required for diagnosis. 3 The absence of this finding does not exclude CRPS 3.

Pain out of proportion to the injury is the earliest and most consistent finding—this should trigger immediate consideration of CRPS even before other signs develop 1, 3.

Essential History Elements

Document the following 2, 1:

• Precipitating event: CRPS typically follows fractures (most common), limb trauma, surgery, or immobilization 4, 2, 1
• Time course: Symptoms usually develop within weeks to months after the inciting event 1
• Pain characteristics: Burning, aching quality; worsened by movement, light touch, or temperature changes 1, 3
• Functional impact: Inability to use the affected limb, sleep disturbance 5

Physical Examination Findings

Systematically assess 1, 3:

• Sensory: Test for allodynia (pain with light touch), hyperalgesia (exaggerated pain response to pinprick) 1
• Vasomotor: Compare skin temperature bilaterally (use thermometer if available), observe color changes (red, blue, pale, mottled) 1, 3
• Sudomotor: Look for asymmetric sweating or dry skin 1
• Motor: Assess range of motion, strength, presence of tremor or dystonia 1
• Trophic: Examine for edema (measure limb circumference), skin changes (shiny, thin), abnormal hair or nail growth 1, 3

Differential Diagnosis—Critical Exclusions

Before diagnosing CRPS, you must exclude vascular emergencies and treatable structural lesions:

• Acute limb ischemia: Check pulses with handheld Doppler; absent pulses demand emergency vascular surgery consultation within 6 hours 6, 7
• Acute compartment syndrome: Pain out of proportion, pain with passive stretch, tense compartment; requires emergency fasciotomy 8
• Nerve entrapment or impingement: Consider imaging if focal neurological deficits suggest surgically treatable lesion 2
• Infection: Cellulitis, osteomyelitis; initiate antibiotics promptly if suspected 8
• Deep vein thrombosis: Unilateral edema with warmth; obtain venous Doppler 2

Initial Management

Physical therapy is the cornerstone and first-line treatment for CRPS and should be initiated immediately upon diagnosis. 5

Treatment Algorithm by Severity

Mild CRPS

• Physical therapy alone with graded motor imagery and desensitization exercises 2, 5
• Goal: Restore function and prevent progression 5

Mild to Moderate CRPS

• Physical therapy PLUS adjuvant analgesics: 5
  • Anticonvulsants (gabapentin, pregabalin) for neuropathic pain 5
  • Antidepressants (tricyclics, SNRIs) for neuropathic pain 5
• Add opioid if insufficient analgesia to allow participation in physical therapy 5

Moderate to Severe CRPS

• Physical therapy PLUS regional anesthetic blockade (sympathetic or somatic nerve blocks) to enable participation in therapy 5
• Consider corticosteroids in early inflammatory phase (first 3 months) 4
• Consider bisphosphonates for bone pain and trophic changes 4

Refractory Chronic CRPS

• Multidisciplinary approach: 5
  • Continue physical therapy 5
  • Psychological support (cognitive-behavioral therapy) 5
  • Spinal cord stimulation (strongest evidence for refractory cases) 2, 5
  • Intrathecal analgesia 5

Specific Pharmacological Options

Evidence-based medications include: 4, 2

• Neuropathic pain agents: Gabapentin, pregabalin, tricyclic antidepressants, SNRIs 4, 5
• Corticosteroids: Prednisone 30-40 mg daily tapered over 2-4 weeks (early inflammatory phase only) 4
• Free radical scavengers: N-acetylcysteine, vitamin C (prophylaxis in fracture patients) 4
• Bisphosphonates: Alendronate, pamidronate for bone pain 4
• Calcitonin: For bone metabolism abnormalities 4

Investigational therapies with emerging evidence: 2

• Ketamine infusions 2
• Botulinum toxin 2
• Intravenous immunoglobulin 2

Critical Management Principles

Early diagnosis and immediate treatment initiation are essential—delayed treatment significantly worsens prognosis 5. Most patients, particularly younger individuals, recover gradually with appropriate early intervention 2.

Physical therapy must be maintained throughout treatment regardless of other interventions; it is the only intervention with consistent evidence across all severity levels 5.

Re-evaluate non-recovering patients for surgically treatable causal lesions (nerve entrapment, impingement, infections, tumors) and potentiating conditions (polyneuropathy, circulatory insufficiency) 2.

Prognosis

Most patients recover with early, aggressive treatment, but a small percentage develop refractory chronic pain requiring long-term multidisciplinary management. 5 Females have substantially higher risk of developing CRPS, and workplace accidents are a well-recognized cause 2.