Prospective follow-up study of chronic polyneuropathy of undetermined cause

Forty consecutive patients with chronic sensorimotor polyneuropathy of undetermined cause were followed to determine disease progression and prognosis. They had had neurological symptoms for at least 1 year before presentation. Neurophysiological examination in all patients showed chronic axonal degeneration, which was confirmed by sural nerve biopsy. Patients were reviewed every 3 months. Laboratory tests were performed every 6 months for the first 2 years and then annually. Neurophysiological examination was performed annually in all patients. Patients were followed up for at least 4 years. In no instance was a possible etiological factor detected during follow-up. The clinical and electrophysiological findings had a slowly progressive course. We suggest that patients with a chronic polyneuropathy of undetermined cause despite detailed investigations do not require further extensive and expensive laboratory tests and neurophysiological studies during follow-up.