Nitrous oxide induced subacute combined degeneration with longitudinally extensive myelopathy with inverted V-sign on spinal MRI: a case report and literature review

Nitrous oxide (N2O), a long-standing anesthetic, is also neurotoxic by interfering with the bioavailability of vitamin B12 if abused. A few case studies have reported the neurological and psychiatric complications of N2O. Here, we reported a patient of N2O induced subacute combined degeneration (SCD) with longitudinally extensive myelopathy with inverted V-sign exhibiting progressive limb paresthesia and unsteady gait. This case raises the awareness of an important mechanism of neural toxicity of N2O, and clinical physicians should be well recognized this in the field of substance-related disorders.