Nitrous Oxide-Induced Neuropathy among Recreational Users in Vietnam

Abstract

Nitrous oxide (N2O) commonly referred to as laughing gas, has significant medical uses. This study aims to describe the neurological disorders associated with N2O. We conducted across-sectional study that enrolled patients with nitrous oxide toxicity admitted to Vietnam Poison Control Center, Bach Mai Hospital, Hanoi, Vietnam from June 2018 to July 2019. The questionnaire included demographic characteristics, characteristics of using N2O, signs and clinical symptoms, neuroimaging findings, injury on electromyography (EMG) and the Total Neuropathy Score clinical version (TNSc) criteria. A total of 47 participants were included with mean age: 24.38 ± 6.20 years. The number of balloons used per week was 130.59 ± 117.43. The mean duration of N2O exposure was 8.79 ± 7.1 months. Multivariate linear logistic regression revealed that the number of N2O balloons used per week was significantly associated with TNSc point (Beta: 0.315; 95% CI: 0.001–0.022). We found that myeloneuropathy and peripheral neuropathy were the main neurological disorders related to N2O abuse, which should improve the awareness of the appearance of neurological disorders associated with N2O abuse.

The Clinical Presentations of Nitrous Oxide Users in an Emergency Department

“…In our study, eight of 21 (38%) patients initially had a low serum vitamin B12 level. The prevalence of vitamin B12 deficiency among N 2 O abusers was similar to other studies [ 37 ]. A total of 12 of 14 (85.7%) patients presented an elevated homocysteine level.…”

“…Therefore, interpreting the results, such as prevalence, was not suitable. Therefore, the finding of high prevalence of concomitant abuse in our study may be biased as well, even though our patient number was relatively bigger than or similar to the previous studies [ 4 , 6 , 37 , 39 , 40 ]. Studies of higher evidence should be carried out for a better interpretation of this issue.…”

Review article: Clinical manifestations and outcomes of chronic nitrous oxide misuse: A systematic review

“…Most case series reported neurological complaints with 23 studies reporting presentations of sensory change, weakness or autonomic dysfunction, [17][18][19][20][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] whereas seven described psychiatric symptoms. 18,21,23,27,30,31,33 Other conditions reported included hyperpigmentation, 22,25,39 pruritis 25 and haematological sequelae. 25 Case report findings are summarised in Table 2.…”

“…Serum B12 levels were described in 21 case series [17][18][19][20][22][23][24][25][26][27][28][29]31,[33][34][35][36][37][38][39][40] with 243 reported values; of which 111 were low, 126 were normal and six were high. Homocysteine, MMA, haemoglobin and MCV were described in 19, [18][19][20][22][23][24][25][26][27][28][29][31][32][33][34][35][37][38][39] five 24,26,34,35,37 and 12, 18,20,[23][24][25]27,…”

“…MRI spine results were reported in 21 case series with dorsal column abnormalities demonstrated in 18 studies, [17][18][19][20][22][23][24][25]27,[29][30][31][32][33][34][37][38][39] lesions of unspecific location in one study 28 and two reported no cord lesion. 35,40 Cerebral white matter changes were identified in two case series.…”