Peripheral sympathetic function in patients with a polyneuropathy.

Abnormal peripheral vasoconstrictor responses to inspiration were found in the finger tips of 11 out of 20 patients with a suspected polyneuropathy, most of whom had no clinical evidence of autonomic involvement. Among these 11 patients the neuropathy involved both motor and sensory fibers in 9, sensory fibers alone in 1, and autonomic fibers alone in another; it was accompanied by electrical changes suggestive of axonal degeneration in 9 patients, and by normal findings in 1, while the remaining patient was not investigated electrophysiologically. In addition to conventional electrophysiological tests of somatic motor and sensory function, it is suggested that peripheral vasomotor function be evaluated when patients with a polyneuropathy are being investigated, in order to identify the spectrum of nerve fibers that are involved and thereby characterize the disorder more fully.