Ten steps in characterizing and diagnosing patients with peripheral neuropathy.

Cost-effective approaches for arriving at correct diagnoses should be used. Herein, we compare three approaches for the differential diagnosis of a common neurologic syndrome, peripheral neuropathy. In the "shotgun" approach, a standard battery of hematologic, biochemical, serologic, antibody, enzyme, molecular genetic, and other tests are ordered after the presence of a neuropathy is established, without a detailed characterization of the neuropathy. In the "gestalt" approach, the specific variety of neuropathy is identified by recognition of a clinical pattern of symptoms, course, or disease associations. The "10-step" approach, encompassing components of the two other methods and adding others, evolved from our assessment of many patients with peripheral neuropathy. In the 10-step approach, the history and neurologic examination place the patient's disorder into one of perhaps 21 anatomic-pathologic patterns. Next, electrophysiologic and other tests confirm the correctness of this anatomic-pathologic patterns. Finally, a series of evaluations exclude or include an increasingly shorter list of diagnoses until only one likely one remains or the disorder remains undiagnosed. We advocate the 10-step over the shotgun or gestalt approach, because it emphasizes careful initial characterization of neuropathy and emphasizes use of a logical step-by-step inclusion or exclusion to arrive at a short list of diagnostic possibilities. The approach depends ultimately on the judgement of adequately trained and experienced physicians, not on the results of single tests. The 10-step approach is not a mindless algorithm, leading inevitably to the correct diagnosis, but depends on judgment based on extensive background and neurobiologic and clinical knowledge and training.