Neurological Impairment in a Young Population Exposed to Recreational Nitrous Oxide

Recruiting

• Conditions: Neuropathy
• Interventions: Other: None, pure observationnal study

• Registration Number: NCT05469321
• Lead Sponsor: Centre Hospitalier Universitaire de Nīmes

Brief Summary

Nitrous oxide (N2O) is a colorless, flammable, analgesic gas used in surgery and dentistry. The consumption of N2O has increased among young French people aiming to relax because of its short-lived neuropsychological effect (euphoria, depersonalization, analgesia) and its wide availability on the market.

It can be responsible in case of prolonged use and overdose of a vitamin B12 deficiency with possible neuropsychiatric complications: sensitivomotor neuropathy, myelopathy, behavioral and cognitive disorders of acute or sub-acute installation.

N2O inhibits the activitý of methionine synthase, decreases the activitý of methylmalonyl-CoA mutase leading to vitamin B12 deficiency but in addition to the interference with vitamin B12 metabolism there seems to be a direct toxicity of N20.

Myelin alteration was the typical electromyography finding but new axonal profiles were also described. Since myelopathy affects both the posterior and lateral cords, combined spinal cord sclerosis is the most common location of injury associated with N2O intoxication.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2022-07-19
• Study First Submitted QC: 2022-07-19
• Study First Posted: 2022-07-21
• Study Start: 2022-08-22
• Status Verified: 2024-01
• Last Update Submitted: 2024-01-12
• Last Update Posted: 2024-01-16
• Primary Completion: 2024-12
• Study Completion: 2024-12

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Patients	None, pure observationnal study	patients presenting to the CHU of Nîmes for an acute or subacute neurological picture after having consumed N2O.

Primary Outcome Measures

Name	Time	Method
INCAT Sensory Sum score (ISS)	Baseline	grades from 0 (no involvement) to 20 (severe involvement)
ONLS - Overall Neuropathy Limitations Scale	Baseline	Overall Neuropathy Limitation Scale = arm scale (range 0 to 5) + leg scale (range 0 to 7); (range: 0 (no disability) to 12 (maximum disability)
vitamin B12 level	baseline	vitamin B12 level in µmom/L
MRC score	baseline	MRCss - Medical Research Council sum score : This score assigns a rating to each muscle group: "0" = absence of visible contraction visible contractions, " 1 " = visible contractions without movement of limbs, " 2 " = insufficient 2" = insufficient movements to overcome weightlessness, "3" = movements to overcome weightlessness, "4" = movements against weightlessness and resistance, "5" = normal muscle strength.
electroneuromyogram	baseline	Normal Yes/No
Romberg score	Baseline	A positive Romberg test means the presence of sensory ataxia
Rankin score	Baseline	disability measurement score from 0 (none) to 6 (death)
Cerebral MRI	baseline	lesions yes/No
methyl malonic acid level	baseline	methyl-malonic acid level
Pan-medullary MRI	baseline	lesions yes/No

Trial Locations

Locations (1)

CHU de Nîmes; 🇫🇷 Nîmes, France