Analysis of clinical characteristics and prognostic factors in 110 patients with nitrous oxide abuse

Abstract

Purpose: To review the clinical symptoms, auxiliary examination findings, and outcomes of patients with nitrous oxide (N 2 O) abuse, and analyze the factors that affect outcomes. Methods: Patients with N 2 O abuse treated in the Department of Neurology between January 2018 and December 2020 were included. The clinical data of these patients were collected, and follow-up was conducted to determine the outcomes. Results: The average age of the 110 patients with N 2 O abuse was 21.4 ± 4.2 years (range: 14-33 years). Clinical presentation primarily included neurological symptoms, such as limb numbness and/or weakness (97%), psychiatric symptoms, changes in appetite, and skin hyperpigmentation. Laboratory test results were characterized by vitamin B 12 deficiency (60%, 34 out of 57 cases) and high homocysteine level (69%, 31 out of 45 cases). Electromyography indicated mixed axonal and demyelination injury (92%, 80 out of 87 cases). Motor and sensory nerves were simultaneously involved, and injury primarily involved the lower limbs. One hundred and seven (97%) patients were clinically diagnosed with peripheral neuropathy, of whom 26 (24%) exhibited spinal abnormalities on magnetic resonance imaging, supporting a diagnosis of subacute combined degeneration. Treatment included N 2 O withdrawal and vitamin B 12 supplementation. Reexamination of six patients indicated that treatment was effective. Follow-up was completed for 51 patients. Thirty-four patients (67%) recovered completely, 17 patients (33%) had residual limb numbness, and only one patient experienced relapse. Sex was an independent prognostic factor; the outcomes of female patients were better than that of male patients. Conclusion: The recreational use of N 2 O has largely expanded among youth in recent decades, which has become a growing public health concern in China. It highlights the importance of the recognition of various clinical symptoms, particularly limb numbness and/or weakness related to the cases of N 2 O abuse. The therapeutic administration of vitamin B 12 supplementation and N 2 O withdrawal can make the overall prognosis good, especially for female patients.

Case report: Recreational nitrous oxide abuse triggered peripheral neuropathy possibly through the immune-mediated pathogenesis

“…These patients primarily exhibited limb numbness or weakness, especially the lower limbs. Decreased muscle strength, superficial sensory disturbances, and decreased tendon reflex were the most common neurological signs according to the published report (7). Increased plasma homocysteine level is more sensitive than plasma vitamin B12 level for clinical diagnosis, as N 2 O mainly consumes vitamin B12 in tissue but not blood (3).…”

“…Peripheral neuropathy is the most common N 2 O-related neurological disorder with a morbidity up to 97% ( 7 ). These patients primarily exhibited limb numbness or weakness, especially the lower limbs.…”

A man in his twenties with weakness and numbness in his legs

“…Lystgassindusert nevropati beskrives typisk hos unge mennesker i 20-årene og rammer i bemerkelsesverdig grad mest underekstremitetene, med symptomer som inkluderer varierende grad av ustøhet, nummenhet og svakhet (11,12). Nevrofysiologisk beskrives oftest en sensorimotorisk nevropati med blandet aksonal og demyeliniserende affeksjon.…”

High Incidence of Signs of Neuropathy and Self-Reported Substance Use Disorder for Nitrous Oxide in Patients Intoxicated with Nitrous Oxide

“…A Dutch study in patients intoxicated with N 2 O reported that 38% of the patients showed signs of neuropathy [1]. The literature showed that 36–98% of patients who presented in the hospital with N 2 O abuse showed signs of neuropathy [16, 17]. Supplementation with vitamin B12 could reverse damage, provided that N 2 O use is discontinued [18, 19].…”