Diagnosis and Management of Complex Regional Pain Syndrome

Diagnosis and Management of Complex Regional Pain Syndrome

ABSTRACT: Complex regional pain syndrome (CRPS) can be tricky to diagnose. The International Association for the Study of Pain established criteria that differentiated CRPS as type 1 (formerly called "reflex sympathetic dystrophy") or type 2, associated with nerve injury (formerly called "causalgia"); patients also had to have pain disproportionate to the inciting event. Newer, stricter criteria have been proposed that cluster signs and symptoms and require documentation of objective findings as well as symptoms reported by the patient. The key to identifying CRPS is to obtain a proper history, document objective findings, and rule out other disorders that can imitate the condition. Treatment tends to be multifaceted; it includes physical mobilization of the affected limb and medications to help alleviate discomfort. (J Musculoskel Med. 2008;25:464-469, 490)

Silas Weir Mitchell (1829-1914) described "causalgia" after nerve injury during the American Civil War. Over time, the syndrome was given multiple and colorful names, such as algodystrophy, sympathalgia, and posttraumatic spreading neuralgia. The term "reflex sympathetic dystrophy" (RSD) attributed to Evans in 1946 referred to a clinical syndrome similar to that observed in causalgia but in the absence of overt nerve injury. Both entities were renamed "complex regional pain syndrome" (CRPS) at the Orlando consensus workshop in 1993, and new criteria were adopted in 1994 by International Association for the Study of Pain (IASP) taxonomy.1

complex regional pain syndrome CRPS type 1 leg swelling
Figure 1 Swelling is seen in the right leg
of a patient with complex regional pain
syndrome type 1.

The criteria described CRPS type 1 (formerly known as RSD) and type 2 (formerly known as causalgia) as syndromes (a) arising after an initiating noxious event in the absence (CRPS 1) or the presence of overt nerve injury (CRPS 2); (b) with spontaneous pain or allodynia/hyperalgesia not limited to the territory of a single peripheral nerve (for CRPS 1) and disproportionate to the inciting event; (c) with past or present evidence of edema, skin blood flow abnormality, or abnormal sudomotor activity; and (d) excluding other conditions that would otherwise account for the degree of dysfunction.

This taxonomy was meant to be descriptive and general rather than implying etiology or pathophysiology.1 It acknowledged that in some cases the sympathetic nervous system (SNS) may be involved, but the mandatory and all-inclusive role of SNS was minimized. In this article, we discuss the diagnosis and management of CRPS, with emphasis on CRPS 1.

Figure 2 In a patient with recalcitrant complex
regional pain syndrome type 1 (photograph taken
while the patient was under general anesthesia),
fixed dystonic posturing was established within
3 months even though sympathetic blocks,
opioid analgesics, neuropathic medications,
and aggressive therapy were used.


Figure 3 A patient with complex regional pain syndrome type 1 had fixed posturing associated with coldness and profound allodynia 1 year after injury (A). The patient had been immobilized inappropriately in the "position of comfort" early after injury without much therapy to mobilize the extremity (B).


Figure 4 A patient with complex regional pain syndrome type 2 has a lateral plantar nerve laceration (A). Widespread severe allodynia has resulted in dry scaly skin because the patient has been unable to wash the foot for 1 year (B).


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