Reversible Neuropsychiatric Disturbances Caused by Nitrous Oxide Toxicity: Clinical, Imaging and Electrophysiological Profiles of 21 Patients with 6-12 Months Follow-up

Rui Zheng; Qinzhou Wang; Mingyuan Li; Fuchen Liu; Yongqing Zhang; Bing Zhao; Yuan Sun; Dong Zhang; Chuanzhu Yan; Yuying Zhao; Wei Li

doi:10.2147/NDT.S270179

Reversible Neuropsychiatric Disturbances Caused by Nitrous Oxide Toxicity: Clinical, Imaging and Electrophysiological Profiles of 21 Patients with 6-12 Months Follow-up

Neuropsychiatr Dis Treat. 2020 Nov 23:16:2817-2825. doi: 10.2147/NDT.S270179. eCollection 2020.

Authors

Rui Zheng^#¹, Qinzhou Wang^#², Mingyuan Li³, Fuchen Liu⁴, Yongqing Zhang¹, Bing Zhao¹, Yuan Sun¹, Dong Zhang², Chuanzhu Yan^{1

2}, Yuying Zhao², Wei Li²

Affiliations

¹ Department of Neurology, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao City, People's Republic of China.
² Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan City, People's Republic of China.
³ EMG-Evoked Potential Room, Binzhou Medical University Hospital, Binzhou City, People's Republic of China.
⁴ Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA.

^# Contributed equally.

Abstract

Purpose: Nitrous oxide (N₂O) abuse has become an increasingly severe problem in China. The aim of the study was to summarize the features of N₂O-induced neurology and enhance the awareness of this disease among physicians.

Patients and methods: We retrospectively reviewed the clinical, imaging, electrophysiological characteristics and the prognosis of patients with N₂O neurotoxicity in our hospital from January 2016 to August 2019.

Results: Twenty-one patients (average age: 22.6±4.6 years) were collected. Eighty-six percent (18/21) patients presented with acute or subacute neurological disorders as their initial symptoms. The remaining fourteen percent (3/21) had psychiatric symptoms as the earliest symptoms. With progression, movement dysfunction appeared in ninety percent (19/21) of the patients with fifty-three percent (10/19) presented with weakness limited to both lower extremities. Sixty-two percent (13/21) of the patients presented with subjective sensory deficit. Seventy-one percent (15/21) had vibration sense impairment and positive Romberg's sign. Sixty-seven percent of the patients had hyporeflexia or areflexia. Fourteen percent (3/21) showed positive Babinski's sign. Seventy-eight percent (14/18) showed significantly increased homocysteine (HCY) level and only seventeen percent (3/18) showed decreased serum vitamin B₁₂ level. T₂ hyperintensity involving the posterior columns and lateral columns with inverted V sign in cervical spinal MRI had been observed in forty-seven percent (8/17) of the patients. Axonal peripheral neuropathy occurred in eighty-five percent (17/20) of the patients. The level of serum vitamin B₁₂ and HCY, as well as imaging findings, were rapidly recovered after supplementation of Vitamin B₁₂.

Conclusion: The N₂O-induced neuropsychiatric disturbances mainly occurred in the young groups and should be recognized by clinicians. The prognosis of N₂O intoxication is relatively good.

Keywords: nitrous oxide toxicity; peripheral neuropathy; psychiatric disturbance; subacute combined degeneration; vitamin B12 deficiency.