Recreational nitrous oxide abuse related subacute combined degeneration of the spinal cord in adolescents - A case series and literature review.

Nitrous oxide (N₂O) is a commonly used inhaled anesthetic in outpatient dental procedures. However, the increasing recreational use of N₂O may result in vitamin B₁₂ deficiency-related neurologic and psychiatric symptoms. The aim of this study was to demonstrate the clinical features of chronic N₂O abuse in pediatric patients.

Patients under 20 years of age who were diagnosed with N₂O-induced subacute combined degeneration of the spinal cord from 2012 to 2018 were enrolled in this study. Clinical presentations, laboratory, imaging, ancillary studies, treatments and outcomes were analyzed.

Nine patients were included, all of whom presented with symptoms of myeloneuropathy including limb numbness, limb weakness or unsteady gait. Six patients had low or low-normal vitamin B₁₂ (cyanocobalamin) levels. Eight patients had evidence of subacute combined degeneration of the spinal cord via neuroimaging studies. All of the patients received vitamin B₁₂ supplementation as treatment. All had full recovery of muscle power within 2 months. Five patients had persistent sensory deficits.

Chronic N₂O abuse can cause permanent neurological damage if not treated promptly. Clinical staff should be aware of the various presentations of neurotoxicity related to N₂O abuse.