Diphtheritic neuropathy, an analysis based on muscle and nerve biopsy and repeated neurophysiological and autonomic function tests.

A patient with diphtheritic neuropathy was investigated with repeated tests of parasympathetic and sympathetic vasomotor and sudomotor functions for one year after the onset of symptoms. Somatic nerve function was tested with nerve conduction studies and an index based on ten variables was used to follow the course of the neuropathy. Sural nerve and anterior tibial muscle biopsies were performed. A severe but shortlasting impairment of the parasympathetic vagal reflex arc was found. The recovery of this function paralleled the clinical course. Sympathetic functions were normal. The neurophysiological variables of somatic nerve function showed signs of a mainly demyelinating mixed sensory/motor neuropathy. The recovery of these variables was slow. The nerve and muscle biopsies demonstrated mild changes consistent with a mixed, demyelinating, non-inflammatory neuropathy.