Diagnostic investigation of patients with chronic polyneuropathy: evaluation of a clinical guideline

Objective-(1) To evaluate a clinical guideline for the diagnostic investiga tion of patients presenting with signs and symptoms (present for longer tha n 6 weeks) suggesting a chronic polyneuropathy. (2) To investigate the cont ribution of electrophysiological studies to a focused search for aetiology in these patients. Methods-A chart review was carried out of a consecutive group of outpatient s in 1993-7 at a university department of neurology, with signs and symptom s suggesting a polyneuropathy in whom the diagnostic investigation had been carried out according to a recently introduced guideline. Diagnostic tests were performed and final diagnoses were made. Results-Unnecessary investigations were carried out in 108 (51%) of 213 pat ients and too few tests in 23 (11%) of these patients. In 82 (48%) of the 1 72 patients who fulfilled the inclusion criteria neurophysiological tests d id not contribute to the final diagnosis. Neurophysiological criteria for d emyelination were fulfilled in only 13 (8%) of the 172 patients. Conclusion-In patients presenting with signs and symptoms of chronic polyne uropathy the number of tests in the diagnostic investigation can be conside rably reduced. In patients with signs and symptoms of polyneuropathy, provi ding the clinical phenotype is typical, in the presence of diabetes mellitu s, renal failure, HIV infection, alcoholism, or use of potentially neurotox ic drugs further investigations are non-contributory. The significance of e lectrophysiological studies in the investigation of patients with polyneuro pathy is rather to separate sensorimotor neuropathies from pure sensory neu ropathies than to distinguish between demyelinating and axonal neuropathies .