Nitrous <scp>oxide‐induced</scp> neurological disorders: an increasing public health concern

Abstract

Abstract Background Neurological presentations resulting from nitrous oxide (N 2 O) abuse are increasing in Australia and worldwide. Despite known neuropsychiatric sequelae, N 2 O canisters remain readily available and its use unregulated. Aims To examine the demographics, clinical and electrophysiological findings of patients presenting with neurological complications of N 2 O abuse, and thus inform clinicians and public health decision‐makers of the significant public health concerns of this increasing practice. Methods Consecutive patients presenting to a tertiary referral metropolitan hospital were included in this series. Patients were identified by a search of discharge summaries of patients admitted with acute or subacute neuropathy or myelopathy and a history of N 2 O abuse, and from the electrophysiology database. Results Thirteen patients were identified, most presenting with subacute paraesthesia, sensory ataxia and lower limb weakness. Eleven had low serum vitamin B 12 . Spinal magnetic resonance imaging was consistent with subacute combined degeneration in eight. Nerve conduction studies revealed a motor or sensorimotor axonal neuropathy (three with motor predominance). There was a bimodal demographic distribution consisting of socially isolated, international university students and local residents with a history of mental illness and polydrug abuse. Conclusions Recreational N 2 O use is an emerging health problem in Australia. International university students and patients with pre‐existing mental illness or polydrug use appear to be at increased risk. A severe motor neuropathy may emerge following vitamin B 12 replacement. Public health measures are required to limit the availability of N 2 O and to educate adolescents and young adults about the potential for significant harm.

Topics & Concepts