Clinical, electrophysiological and radiological features of nitrous oxide-induced neurological disorders.

Purpose: We summarized the clinical manifestations, laboratory and electrodiagnostic characteristics and magnetic resonance imaging (MRI) findings of nitrous oxide (NO) abuse-induced neurological disorders. Patients and Methods: We retrospectively reviewed 33 patients with NO abuse-induced neurological disorders and reported their demographic data, clinical manifestations, laboratory examinations, nerve conduction studies, together with spinal and brain MRI. Results: The most frequent clinical manifestations included numbness and weakness in the extremities and unspecified gait disturbance. Low serum vitamin B levels were found in 9 patients, and high homocysteine levels were noted in 27 patients. Nerve conduction studies showed a sensory-motor neuropathy. Sixteen patients showed bilateral high-intensity T2 signal within the posterior column on spinal MRI, and four patients showed cerebral white matter lesions on brain MRI. Conclusion: NO abuse has become a significant public health problem because of the severe neurological disorders related to chronic abuse. Clinical physicians should be aware of the toxic effects of NO