Clinical trial NCT05329909: Epidemiology of Neurological Complications to Nitrous Oxide Poisoning
Official title: Epidemiology of Neurological Complications to Nitrous Oxide Poisoning
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Neurology Department
Keywords: nitrous oxide poisoning
Lead sponsor: Centre Hospitalier de Saint-Denis
Sponsor class: OTHER
First posted: 2022-04-15
Enrollment: 135
Sex: ALL
Minimum age (years): 16
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: cohort of patients who have been exposed to N2O and have neurological disorders

Brief summary: N2O inactivates vitamin B12, impairing its ability to act as a cofactor of methionine synthase. In addition, the elimination of vitamin B12 is increased. Neurological damage is similar to that described in combined sclerosis of the marrow, and are probably related to induce vitamin B12 deficiency. The use of N2O can then precipitate the rapid appearance of signs (neurological, psychiatric and hematological) related to a true and/ or functional vitamin B12 deficiency.

In 1978, RB Layzer described the first 3 cases of peripheral neuropathy secondary to nitrous oxide (N2O) consumption. In 2016, a team collected the 91 published cases: among these, 72 had neurological complications, and 52 had a concentration of vitamin B12 considered "low" or "normal-low"

Since then, consumption patterns seem changed due to: an increasing ease of access, the change of container (packaging in cartridge 8 grams versus bottle of 600 grams) and a usually occasional and festive consumption that seems to become solitary and regular, This change in consumption patterns is explained by an increased incidence of neurological complications, although no epidemiological work is yet available.

The objective of this work is to describe the epidemiology of this condition, to correlate it with major recent social phenomena (confinement related to the SARS-Cov2 pandemic), and finally to compare the incidence of myelopathies secondary to N2O with the incidence of other frequent inflammatory neurological diseases (autoimmune myelitis and Guillain-Barré syndrome).


Eligibility criteria: Inclusion Criteria:

* Adult patient (≥16 years)
* Hospitalized or having consulted with the departments of Neurology or Internal Medicine for neurological phenomena related to the consumption of N2O. The neurological phenomena included are usually: neuropathies or myelopathies, However, the existence of other neurological or psychiatric signs is not a factor of exclusion: for example, headaches or cognitive or psychiatric disorders with acute onset.
* Exposure to N2O for recreational or medical reasons (Meopa anesthesia).
* Lack of alternative diagnosis other than N2O poisoning
* Consultation for neurological disorders between 01/01/2018 and 31/12/2021

Exclusion Criteria:

* Minor subjects or subjects subject to a legal protection measure (guardianship, curators) during the consultation.
* Refusal to include in a study explained in the file
* Absence of N2O consumption during the 6 months preceding the appearance of signs

Primary outcomes:
measure: sexe
timeFrame: Day 1
measure: age
timeFrame: Day 1
measure: place to live
timeFrame: Day 1
measure: Occupational status
timeFrame: Day 1
measure: consumption of toxic substances (alcohol, tobacco, cannabis)
timeFrame: Day 1
Secondary outcomes:
measure: Date and nature of first symptoms
timeFrame: Day 1
measure: consumption mode and quantity
timeFrame: Day 1
Other outcomes:
measure: detail of symptoms, origin and consequences
timeFrame: Day 1
Locations:
city: Saint-denis
country: France
facility: Hôpital DELAFONTAINE
state: ILE DE France
Study officials:
References:
citation: Layzer RB, Fishman RA, Schafer JA. Neuropathy following abuse of nitrous oxide. Neurology. 1978 May;28(5):504-6. doi: 10.1212/wnl.28.5.504.
citation: Sanders RD, Weimann J, Maze M. Biologic effects of nitrous oxide: a mechanistic and toxicologic review. Anesthesiology. 2008 Oct;109(4):707-22. doi: 10.1097/ALN.0b013e3181870a17.
citation: Garakani A, Jaffe RJ, Savla D, Welch AK, Protin CA, Bryson EO, McDowell DM. Neurologic, psychiatric, and other medical manifestations of nitrous oxide abuse: A systematic review of the case literature. Am J Addict. 2016 Aug;25(5):358-69. doi: 10.1111/ajad.12372. Epub 2016 Apr 1.
citation: Vollhardt R, Mazoyer J, Bernardaud L, Haddad A, Jaubert P, Coman I, Manceau P, Mongin M, Degos B. Neurological consequences of recreational nitrous oxide abuse during SARS-CoV-2 pandemic. J Neurol. 2022 Apr;269(4):1921-1926. doi: 10.1007/s00415-021-10748-7. Epub 2021 Aug 21.