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Reversible myeloneuropathy of nitrous oxide abuse: Serial electrophysiological studies
Author(s) -
Vishnubhakat S. Murthy,
Beresford H. Richard
Publication year - 1991
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880140105
Subject(s) - medicine , electrophysiology , denervation , anesthesia , electromyography , ataxia , nitrous oxide , motor unit , anatomy , physical medicine and rehabilitation , psychiatry
Detailed electrophysiological studies were performed in 4 patients with myeloneuropathy induced by abuse of nitrous oxide for 1 to 4 years. All presented with paresthesias, weakness, and Lhermitte's phenomena, and exhibited signs of sensorimotor polyneuropathy, ataxia, and arreflexia. Two had subnormal serum vitamin B 12 levels. Baseline electrophysilogic testing revealed reduced motor unit potentials, prolonged F wave latencies, absent H refelxes, denervation potentials, and delays in motor and sensory conduction. Three had peripheral and nuchal delay after median nerve stimulation. All were reevaluated after 3 to 12 months abstinence and treatment with vitamin B 12 , and all showed substantial clinical improvement. Parallel improvement in electrophysiologic findings occurred, but residual minor conduction delays, loss of H reflexes, electromyographic evidence of denervation, or abnormalities of posterior tibial SEP were noted. These findings confirm the reversibility of myeloneuropathy of nitrous oxide abuse and describe the profile of electrophysiologic recovery in subjects who abstain from further neurotoxic exposure.