AXONAL AND DEMYELINATING NEUROPATHY WITH REVERSIBLE PROXIMAL CONDUCTION BLOCK, AN UNUSUAL FEATURE OF VITAMIN-B12 DEFICIENCY

We report a 35-year-old patient with megaloblastic anemia who presente d with features of subacute combined degeneration of the cord. Electro physiological studies showed features of axonal neuropathy. In additio n, there was evidence of prominent focal proximal conduction block in several nerves. After treatment with cyanocobalamin the neuropathy imp roved, and the peripheral nerve conduction block detected earlier disa ppeared. Reversible nerve conduction block as a feature of vitamin B12 deficiency in man, to our knowledge, has not been reported in literat ure, so far. (C) 1998 John Wiley & Sons, Inc.