What are the diagnosis and management of Complex Regional Pain Syndrome (CRPS)?

Complex Regional Pain Syndrome: Diagnosis and Management

Diagnosis of CRPS

CRPS is primarily a clinical diagnosis based on the Budapest Criteria, requiring symptoms present for at least 12 months to be considered chronic, with excruciating pain disproportionate to the initial injury that worsens with touch or stimulation. 1, 2

Clinical Presentation

• Pain characteristics: Excruciating, burning pain that gradually increases in intensity and spreads within the affected limb, sometimes extending to the contralateral limb 3, 1
• Sensory abnormalities: Allodynia (pain from light touch) and hyperalgesia (increased pain sensitivity) are hallmark features 1, 4
• Autonomic dysfunction: Temperature dysregulation, skin color changes (mottling, cyanosis), and abnormal sweating patterns in the affected limb 1, 5
• Motor impairment: Functional limb weakness appearing disproportionate to injury, decreased active range of motion, and altered movement patterns 1, 4
• Trophic changes: Hair loss, tissue changes, skin discoloration, and in chronic cases, muscle atrophy and bone demineralization 3, 1, 5

Diagnostic Criteria Framework

For chronic CRPS (>12 months), diagnosis requires four components: 2

1. General criteria: Budapest Criteria fulfilled for ≥12 months, with CRPS remaining a diagnosis of exclusion 2
2. History-based criteria: At least 3 of 5 specific historical features present 2
3. Physical examination: Asymmetric limb findings, sensory disturbances, and musculoskeletal changes 2
4. Optional diagnostic testing: IENFD assessment, imaging for bone demineralization 2

CRPS Subtypes

• Type I (reflex sympathetic dystrophy): Occurs without identifiable nerve injury 3, 4
• Type II (causalgia): Develops after documented nerve injury 3, 4

Diagnostic Testing

Three-phase bone scintigraphy is the most useful imaging modality, with pooled sensitivity of 78% and specificity of 88%, making it valuable for ruling out disease 3, 5

• MRI: High specificity (91%) but low sensitivity (35%) for CRPS Type I; more useful for Type II to visualize nerve injury and muscle denervation 3
• Ultrasound: Power Doppler shows increased flow in affected limbs with 73% sensitivity and 92% specificity 3
• Radiographs: Insensitive but useful to exclude other pathology; may show bone demineralization in chronic cases 3

Common diagnostic pitfall: CRPS does not demonstrate placebo response except at very early time points (15-30 minutes), distinguishing it from other pain syndromes 3, 6

Management of CRPS

Physical and occupational therapy are the absolute cornerstone and mandatory first-line treatment, with all other interventions serving only to facilitate participation in rehabilitation. 6, 5, 7

First-Line Treatment Algorithm

Step 1: Immediate Physical Rehabilitation (must be initiated regardless of pain severity) 6, 5

• Gentle stretching and mobilization: Focus on increasing external rotation and abduction 6
• Active range of motion exercises: Gradually increase while restoring alignment and strengthening shoulder girdle muscles 6
• Sensorimotor integration training: Graded motor imagery and mirror therapy to address neurocognitive body perception disorders 5, 4
• Weight-bearing activities: Encourage optimal postural alignment and even weight distribution 1

Step 2: Analgesics for Pain Control (to enable physical therapy participation) 6

• NSAIDs/Acetaminophen: First-line pharmacologic agents if no contraindications 6
• Oral corticosteroids: 30-50 mg daily for 3-5 days, then taper over 1-2 weeks to reduce inflammation and edema 6

Second-Line Treatments (When First-Line Insufficient)

Step 3: Neuropathic Pain Medications 4, 7

• Gabapentinoids (gabapentin, pregabalin): Target neuropathic pain component 4
• Antidepressants: Adjuvant analgesics for neuropathic pain 7
• Opioids: Add only if above medications insufficient to allow physical therapy participation 7

Step 4: Sympathetic Nerve Blocks (for moderate to severe cases with sympathetic dysfunction) 6, 7

• Stellate ganglion blocks (upper extremity) or lumbar sympathetic blocks (lower extremity): Use only when there is consistent improvement and increasing duration of relief with each successive block 6
• Critical requirement: Must be integrated into multimodal rehabilitation, not used as monotherapy 6
• Continuation criteria: Document progressive improvement with each block; discontinue if no increasing duration of relief 6
• Contraindication: Do NOT use sympathetic blocks for non-CRPS neuropathic pain 6

Step 5: Adjunctive Interventions 6

• Botulinum toxin injections: When pain relates to spasticity 6
• Subacromial corticosteroid injections: When pain relates to subacromial inflammation 6

Advanced Treatments for Refractory Cases

Step 6: Neuromodulation (only after failure of above treatments and only in specialized centers) 6, 5, 4

• Spinal cord stimulation: Best evidence among interventional procedures; requires trial before permanent implantation 6, 5, 4
• Dorsal root ganglion stimulation: Emerging option with promising results 5, 4, 2
• TENS: Use as part of multimodal approach, not monotherapy 6

Critical caveat: Interventional procedures should be limited to exceptional cases and performed only in specialized centers 5

Psychological Support (Integrated Throughout Treatment)

• Stepped psychological interventions: Reduce anxiety and avoidance behavior that perpetuate disability 5
• Cognitive behavioral therapy: Demonstrated beneficial effect in multiple studies 8
• Address comorbidities: Treat depression and anxiety concurrently 8

Treatment Pitfalls to Avoid

• Never delay physical therapy waiting for pain to resolve—this worsens outcomes through disuse and pain upregulation 5, 7
• Do not continue sympathetic blocks indefinitely without documented progressive improvement and increasing duration of relief 6
• Avoid peripheral somatic nerve blocks for long-term treatment—these are not indicated 6
• Do not use sympathetic blocks for non-CRPS neuropathic pain—this contradicts evidence-based guidelines 6
• Document objective functional outcomes (ADLs, work capacity, autonomic stability) beyond pain scores to justify continued interventional treatment 6

Monitoring and Follow-Up

• Evaluate at least twice annually by a specialist due to high recurrence risk 1
• Monitor for systemic symptoms: Neurocognitive disorders of body perception and symptom processing accompany regional findings 5
• Track functional outcomes: Measure improvements in strength, fine motor skills, sensorimotor integration, and participation in daily activities 5, 2