The changes in nerve conduction in acute idiopathic polyneuritis.

In acute idiopathic polyneuritis weakness of relatively sudden onset sometimes progresses swiftly to severe paralysis. And yet even severely affected patients with this disease may survive with the aid of artificial respiration and apparently recover complete motor and sensory function within several weeks. The nature of the disturbance of nerve conduction underlying this reversible loss of function is not understood and is of considerable interest in view of its relatively rapid time course. There have been reports of slowing of motor conduction velocity in some patients with 'neuritis' (Hendriksen, 1956; Redford, 1958). Lambert (1960) showed a proximal failure of excitability and/or blocking of conduction in the majority of motor fibres, with subsequent recovery, but we are not aware of any detailed serial electrophysiological studies of sensory function in patients with acute idiopathic polyneuritis. In this paper we describe serial electrophysiological studies of both motor and sensory nerve function in such a patient in the hope that they may throw light on the nature of the reversible disturbance of nerve conduction in acute idiopathic polyneuritis. Investigations were started within 12 days of the onset of the illness while the patient required artificial respiration, and they were repeated at intervals subsequently as he recovered.