Imaging appearance of myelopathy secondary to nitrous oxide abuse: a case report and review of the literature

Abstract

Purpose The abuse of nitrous oxide (N₂O) can induce Vitamin B₁₂ deficiency that subsequently leads to central nervous demyelination, myelopathy and peripheral neuropathy. Although myelopathy has been reported in the past, the specific locations and prognosis of the disease are still unclear.

Materials and methods: We report the case of a 22-year-old male who presented with quadriplegia that began after a 3-month history of inhalation of N₂O. We summarized the clinical data of this entity and performed a comprehensive literature review of various presentations and MRI features of myelopathy secondary to N₂O abuse.

Results: In combination with previous reports of 14 cases, we found that the onset of the disease was usually subacute, and the majority of patients (92.85%) were young men. There was no definite relationship between myelopathy and the amount or duration of N₂O inhalation. The most common clinical manifestation was sensory ataxia, and the cervical spinal cord was the most frequently impaired area of the whole spinal cord. The spinal cord lesions had a high signal intensity on T2-weighted MRI and usually involved more than three spinal segments and impaired the posterior column more significantly. Most patients recovered well after vitamin B₁₂ supplementation.

Conclusions: Myelopathy secondary to N₂O abuse is generally seen in young men. The clinical diagnosis mainly depends on a history of N₂O inhalation and the characteristic imaging changes in the posterior cervical spinal cord. Early diagnosis and intervention are important for a satisfactory prognosis.

Keywords: MRI; Nitrous oxide; myelopathy; vitamin B deficiency.