Complex regional pain syndrome

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Background

Abbreviation

  • CRPS

Other Names

  • Reflex sympathetic dystrophy (RSD)
  • Causalgia
  • Reflex neurovascular dystrophy (RND)
  • Amplified musculoskeletal pain syndrome (AMPS)

Definition

  • Disorder of the extremities characterized by regional pain that is disproportionate in time or degree to the usual course of any known trauma or other lesion
  • Pain is not in a specific nerve territory or dermatome
  • Pain usually has a distal predominance of abnormal sensory, motor, sudomotor, vasomotor, and/or trophic findings
  • CRPS often worsens over time
  • 35% of patients report symptoms throughout their whole body.[1]

Sub-Types

Type I NO evidence of peripheral nerve injury (edema, erythema, numbness), 90% of clinical presentations
Type II YES evidence of peripheral nerve injury, considered more serve type

Causes

  • Generally unknown
  • Inciting event
    • Found in about 90% of cases - usually begin 4-6wks after fxs, crush injuries, sprains, and surgery.[2]
  • Proposed mechanisms
    • Classic inflammation, neurogenic inflammation, and maladaptive changes in pain perception at the level of the central nervous system

Clinical Features

Type II CRPS showing skin changes[3]
Pain burning, stinging, or tearing sensation that is felt deep inside the limb, usually continuous but can be paroxysmal.[4]
Sensory hyperalgesia, allodynia, or hypesthesia
Motor weakness, occasional tremor, myoclonus, or dystonic postures
Skin warmth, skin color changes, sweating, or edema, other skin/hair/nail changes

Differential Diagnosis

Evaluation

Clinical: Budapest consensus criteria:

At least 1 symptom in three of the following four categories:

Sensory allodynia, hyperalgesia
Vasomotor temperature asymmetry, skin color changes, skin color asymmetry
Sudomotor edema, sweating
Motor/trophic decreased ROM, weakness, tremor, dystonia, trophic changes (hair, nail, skin)
And, there is no other diagnosis that better explains the signs and symptoms

Rule-Out Emergent Etiologies

Other Imaging

  • CT/MRI/XR are all NOT diagnostic for CRPS[4]

Management

Ketamine for Flare-Ups

  • Initial bolus - 0.2–0.3 mg/kg of infused over 10mins.[3]
    • Avoid IV push - could cause dissociative side effects.
    • Diagnostic- pain should resolve by the end of the 10min bolus and if so, continue
  • Infusion - 0.2 mg/kg/hr over 4-6hrs.

No discharge prescription usually required. If needed:

Opioids should NOT be used for chronic or acute CRPS. Patient education on this is important.

Disposition

  • Outpatient follow-up with pain management
  • Referral for PT/OT - important for all CRPS patients
  • Consider psychiatric referral if warranted

See Also

Acute pain management

External Links

References

  1. ↑ Schwartzman RJ, Erwin KL, Alexander GM (May 2009). "The natural history of complex regional pain syndrome". The Clinical Journal of Pain. 25 (4): 273–80. doi:10.1097/AJP.0b013e31818ecea5. PMID 19590474.
  2. ↑ Sandroni P, Benrud-Larson LM, McClelland RL, Low PA. Complex regional pain syndrome type I: incidence and prevalence in Olmsted county, a population-based study. Pain 2003; 103:199.
  3. ↑ 3.0 3.1 Ducharme, Jim, MD. "Tips for Managing Complex Regional Pain Syndrome - ACEP Now." ACEP Now. N.p., 11 Sept. 2015.
  4. ↑ 4.0 4.1 4.2 Birklein F, O'Neill D, Schlereth T. Complex regional pain syndrome: An optimistic perspective. Neurology 2015; 84:89.
  5. ↑ Harden RN, Oaklander AL, Burton AW, et al. Complex regional pain syndrome: practical diagnostic and treatment guidelines, 4th edition. Pain Med 2013; 14:180.