FWD:Complex REgional Pain Syndrome article by Steven Parrillo

Complex Regional Pain Syndrome : Steven J Parrillo, DO, FACOEP, FACEP,



Background: Reflex sympathetic dystrophy syndrome (RSDS), has been recognized since the Civil War when it was called causalgia, a name chosen to describe intense burning extremity pain after an injury. Since then, RSDS has had a number of name changes. Bonica coined the term reflex sympathetic dystrophy in 1953. The American Association of Hand Surgery proposed changing the name to sympathetic maintained pain syndrome. A consensus expert panel recommended a change to complex regional pain syndrome (CRPS). However, although many clinicians still use the term RSDS, the terms currently in favor are complex regional pain syndrome I (the equivalent of RSD) and CRPS II, also known as causalgia.

CRPS/RSDS has readily identifiable signs and symptoms and is treatable if recognized early; however, the syndrome may become disabling if unrecognized. Emergency physicians are frequently in a position to identify the problem and may play a significant role in minimizing impact of this common entity.


Pathophysiology: No single hypothesis explains all features of RSDS. Schwartzmann states that a common mechanism may be injury to central or peripheral neural tissue. Roberts proposes that sympathetic pain results from tonic activity in myelinated mechanoreceptor afferents. Input causes tonic firing in neurons that are part of a nociceptive pathway. Campbell et al propose a hypothesis that places the primary abnormality in the peripheral nervous system.

Most agree that CRPS is a neurologic disorder affecting central and peripheral nervous systems.

Recent literature suggests 2 new etiologic possibilities. German research has noted the association between elevated levels of soluble tumor necrosis factor receptor 1 (sTNF-R1) and enhanced tumor necrosis factor-alpha activity in patients with polyneuropathy with allodynia. Other German researchers have described autoantibodies in patients with CRPS, especially CRPS type 2.

All agree that, regardless of the mechanism, the patient experiences intense burning pain in one or more extremities.

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