Complex regional pain syndrome type I (RSD) or peripheral mononeuropathy? A discussion of three cases.

OBJECTIVE: Peripheral nerve pathology commonly results in symptoms that suggest a diagnosis of complex regional pain syndrome (CRPS) type I (RSD). We briefly review common symptoms of peripheral nerve pathology (referred pain, hyperpathia, and autonomic changes) and present three illustrative cases of peripheral nerve injury misdiagnosed and treated as RSD. The nonspecificity of current taxonomy regarding CRPS as it relates to the three cases is emphasized.

DESIGN: The study is case series.

SETTING: All three of the cases were diagnosed and treated for their painful symptoms at a university hospital clinic that provides multispecialty evaluations for painful conditions.

PATIENTS: The three patients all had work-related injuries resulting in pain, hyperpathia, and autonomic changes in one of their upper extremities. Their injuries were representative of common peripheral nerve lesions, one being a neuroma, one an irritative lesion, and one an entrapment.

RESULTS AND CONCLUSIONS: The clinical entity of CRPS quite apparently encompasses symptomatology caused by peripheral nerve entrapment, irritative lesions, and neuroma. As such, its use as a diagnostic end point may overlook these treatable conditions. As illustrated in these cases, peripheral nerve pathology may prove a diagnostic challenge and alternative techniques of investigation other than electrophysiologic studies are often helpful.