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

Authors Zheng R, Wang Q, Li M, Liu F, Zhang Y, Zhao B, Sun Y, Zhang D, Yan C, Zhao Y, Li W

Received 7 July 2020

Accepted for publication 18 October 2020

Published 23 November 2020 Volume 2020:16 Pages 2817—2825


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Dr Jun Chen

Rui Zheng,1,* Qinzhou Wang,2,* Mingyuan Li,3 Fuchen Liu,4 Yongqing Zhang,1 Bing Zhao,1 Yuan Sun,1 Dong Zhang,2 Chuanzhu Yan,1,2 Yuying Zhao,2 Wei Li2

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

*These authors contributed equally to this work

Correspondence: Wei Li
Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 Wenhua West Road, Jinan City, Shandong Province 250012, People’s Republic of China
Tel +86-185 60085517

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

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