Complex Regional Pain Syndrome

Aka: Complex Regional Pain Syndrome, Reflex Sympathetic Dystrophy, RSD, Sudeck's Atrophy, Causalgia, Shoulder-Hand Syndrome, Post-traumatic Pain Syndrome

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II. Definitions

  1. Complex Regional Pain Syndrome (CRPS, previously Reflex Sympathetic Dystrophy)
    1. Severe, Chronic Pain and Disability of a limb (part or whole)

III. Pathophysiology

  1. Unclear mechanism
  2. Post-Traumatic inflammatory changes are present in CRPS
  3. Genetic component is likely
    1. Another family member with CRPS is not uncommon
  4. Other mechanisms postulated
    1. Small fiber nerve injury
    2. Sympathetic Nervous System involvement
    3. Emotional response to painful to stimuli

IV. Epidemiology

  1. Incidence: 26 per 100,000 patients
  2. Female predominance (3-4 fold more common)
  3. Peak Incidence age 50 to 70 years old

V. Types

  1. Type I Complex Regional Pain Syndrome (CRPS1) or Reflex Sympathetic Dystrophy (90% of cases)
    1. Not attributable to a specific nerve lesion
  2. Type II Complex Regional Pain Syndrome (CRPS2) or Causalgia
    1. Attributable to a specific nerve lesion
    2. However, resulting Allodynia and hyperalgesia does not follow a single nerve

VI. Risk Factors

  1. Local Trauma (most common)
    1. Limb Fracture (CRPS complicates up to 3-7% of Fractures)
      1. Colles Fracture (28% develop CRPS)
      2. Distal Radius Fracture (3-5% develop CRPS)
    2. Stab or Puncture Wound
    3. Animal Bite
  2. Shoulder-Hand Syndrome
    1. Myocardial Infarction
    2. Cerebrovascular Accident
  3. Routine surgery
  4. Diabetes Mellitus
  5. Malignancy with paraneoplastic syndrome

VII. Associated Conditions

  1. Psychiatric Conditions (esp. Major Depression)
    1. Present in up to half of CRPS cases, but does not appear to have a cause-effect relationship

VIII. Symptoms

  1. Limb pain
    1. Upper limb is affected in 60% of cases
    2. Burning, tingling, stabbing numbness or electric shock-like pain in the distal extremity
    3. Pain is typically out of proportion to initial injury
  2. Onset 4-6 weeks after a mild to moderate limb injury
    1. See precipitating injuries above

IX. Signs

  1. Pain
    1. Burning ache in a non-Dermatome pattern (early)
    2. Hyperalgesia (disproportionate pain to inciting event) develops
    3. Pain does not follow a single nerve innervation pattern (even when the initial cause was nerve related)
  2. Trophic Changes
    1. Early Changes
      1. Local edema
      2. Increased edema, sweating and erythema (hyperemia)
    2. Progressive Changes (esp. trophic changes of hair and nails)
      1. Skin thins
      2. Hair coarsens
      3. Nail thickens
    3. Late Changes
      1. Muscles shorten and atrophy
      2. Joints ankylose moving distal to proximal
  3. Autonomic instability varies by duration
    1. Same limb may have both warm and cold changes simultaneously
    2. Warm Changes (early, first 8 months)
      1. Warm, erythematous, edematous extremity (inflammation)
    3. Cold Changes (later, after 8 months)
      1. Cold, dusky, sweaty extremity
  4. Sensory Abnormalities
    1. Allodynia (exquisite sensitivity to slight touch)
    2. Hyperpathia or Hyperalgesia (severe pain from gentle pressure)
  5. Bony changes
    1. Patchy Osteopenia

X. Stages

  1. Mild (Days to weeks)
    1. Burning pain worse with movement
    2. Edema
    3. Muscle spasm
    4. Patchy Osteopenia may occur
    5. Usually self limited
  2. Moderate (weeks to months)
    1. Pain of local hyperesthesia
    2. Muscle wasting
      1. May radiate up extremity
      2. May affect contralateral extremity
    3. Skin cold and pale
    4. Abnormal bone scan
    5. Requires aggressive treatment
  3. Severe (weeks to months)
    1. Pain from cold and from touch of additional clothing
    2. Loss of mobility of several joints
    3. Psychiatric changes
    4. Aggressive management may be too late

XI. Imaging

  1. XRay (Changes in 85% of cases)
    1. Diffuse Osteopenia in 69% of cases (non-specific)
  2. Vascular Ultrasound
    1. Exclude other diagnoses (e.g. DVT, limb Claudication)
  3. Abnormal bone scan in 50-85% of cases
    1. However, not recommended for clinical evaluation of CRPS

XII. Differential Diagnosis

  1. See Acute Severe Pain Out of Proportion
  2. Musculoskeletal Condition
    1. Stress Fracture
    2. Osteoarthritis
    3. Gouty Arthritis
    4. Pseudogout
    5. Rheumatologic Conditions
    6. Tenosynovitis
  3. Infection
    1. Osteomyelitis
    2. Septic Joint
    3. Soft tissue infection (abscess, Cellulitis, Necrotizing Fasciitis)
  4. Neurovascular conditions
    1. Compartment Syndrome
    2. Radiculopathy
    3. Diabetic Neuropathy
    4. Peripheral Neuropathy
    5. Postherpetic Neuralgia
    6. Charcot Foot
    7. Compression Neuropathy (e.g. Carpal Tunnel Syndrome)
    8. Thoracic Outlet Syndrome
    9. Raynaud Disease
    10. Deep Vein Thrombosis (esp. with Phlegmasia Alba or Cerulea Dolens)
    11. Peripheral Arterial Disease (Claudication)
    12. Central spinal stenosis (pseudo-Claudication)
    13. Buerger Disease

XIII. Diagnosis: Budapest CRPS Criteria

  1. Pain disproportionate to inciting injury AND
  2. No other diagnosis explains signs and symptoms AND
  3. At least 1 Symptom in 3 of the 4 categories
    1. Sensory Abnormalities
      1. Allodynia (exquisite sensitivity to slight touch) OR
      2. Hyperpathia or Hyperalgesia (severe pain from mild pin prick)
    2. Vasomotor
      1. Temperature asymmetry OR
      2. Skin Color asymmetry or changes
    3. Edema or Sweat Changes (Sudomotor)
      1. Edema OR
      2. Sweating asymmetry or changes
    4. Motor or trophic changes
      1. Decreased joint range of motion
      2. Motor dysfunction (weakness, Tremor, Dystonia)
      3. Trophic Changes (nails, hair, skin)
  4. At least 1 Sign in at 2 of 4 categories
    1. Sensory Abnormalities
      1. Allodynia
        1. Exquisite sensitivity to light touch OR
        2. Deep somatic pressure OR
        3. Joint range of motion
      2. Hyperpathia or Hyperalgesia
        1. Severe pain to pin prick
    2. Vasomotor
      1. Temperature asymmetry OR
      2. Skin Color asymmetry or changes
    3. Edema or Sweat Changes (Sudomotor)
      1. Edema OR
      2. Sweating asymmetry or changes
    4. Motor or trophic changes
      1. Decreased joint range of motion
      2. Motor dysfunction (weakness, Tremor, Dystonia)
      3. Trophic Changes (nails, hair, skin)

XIV. Management

  1. Active range of motion ("Move it OR lose it")
    1. Aggressive physical therapy with pain control
    2. Avoid immobilization (e.g. splints, slings)
  2. Physical therapy
    1. Isotonic stength
    2. Passive range of motion
    3. Aerobic Exercises
    4. Pool Exercises
    5. Ergonomic adjustments
  3. Analgesics
    1. NSAIDS (e.g. Ibuprofen or Naprosyn )
    2. Acetaminophen
  4. Antiinflammatory: Medications with best evidence
    1. Oral Corticosteroids
      1. Supported by good quality evidence if given with first 6 months after onset
      2. Prednisone 30-40 mgh orally for 2 to 4 weeks
    2. Bisphosphonates (e.g. Pamidronate 60 mg IV for 1 dose)
      1. Supported by good quality evidence if given within first 6 months of symptoms
  5. Neuropathy agents
    1. Gabapentin (Neurontin)
    2. Pregabalin (Lyrica)
    3. Tricyclic Antidepressant (e.g. Amitriptyline, Nortriptyline)
  6. Topical Medications
    1. Topical Lidocaine Patch (Lidoderm 5% or the OTC Lidocare 4%)
    2. Topical Dimethyl sulfoxide cream (50%) applied for 2 months
      1. May act as free radical scavenger
  7. Novel medications (consult pain management specialists or rheumatology)
    1. Intravenous Immunoglobulin
      1. Goebel (2010) Ann Intern Med 152:152-8 [PubMed]
      2. Goebel (2013) Rheumatology 52 (11): 2091-3 [PubMed]
    2. Lidocaine infusion
      1. Initial: 1.5 mg/kg (1-3 mg/kg) IV over 20-30 min
      2. Later: 0.2 to 2 mg/kg per hour
      3. Wallace (2000) Anesthesiology 92(1):75-83 [PubMed]
      4. Ferrini (2004) J Support Oncol 2(1): 90-4 [PubMed]
  8. Invasive measures (pain management procedures)
    1. Spinal cord stimulation
    2. Intrathecal Baclofen Pump
    3. Sympathetic Nerve block (Stellate Ganglion, Brachial Plexus, lumbar)
      1. Temporary relief
  9. Other measures
    1. TENS Unit (questionable efficacy)
    2. Mental health counseling for patient and family

XV. Prognosis

  1. Longterm Disability is common
    1. Only 20% can participate in prior activities (pain is the limiting factor in >70%)
    2. Schwartzman (2009) Clin J Pain 25(4): 273-80 [PubMed]

XVI. References

  1. Money and Glauser (2017) Crit Dec Emerg Med 31(1): 15-21
  2. Martin in Ruddy (2001) Kelley's Rheumatology, p. 503-4
  3. Bussa (2015) Acta Anesthesiol Scand 59(6): 685-97 [PubMed]
  4. Harden (2013) Pain Med 14(2): 180-229 [PubMed]
  5. Lloyd (2021) Am Fam Physician 104(1): 49-55 [PubMed]
  6. Raja (2002) Anesthesiology 96(5):1254-60 [PubMed]
  7. Turner-Stokes (2011) Clin Med 11(6):596-600 [PubMed]

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