[Acute and chronic toxicities associated with the use and misuse of nitrous oxide: An update]. / Toxicités aiguës et chroniques associées à l'usage et au mésusage du protoxyde d'azote : mise au point.

Nitrous oxide (N2O) is used since the eighteenth century as an anesthetic and analgesic but also for recreational use. If the labelled uses of N2O and their modalities are nowadays perfectly framed, the misuse of N2O takes very alarming proportions among teenagers and young adults. This misuse is the cause of acute (hypoxia, barotrauma, burns, neuropsychiatric disorders) and chronic complications if repeated (myeloneuropathy, anemia, thrombosis, inhalant use disorder). The main mechanism of the latter is mainly related to a functional deficit in vitamin B12 induced by N2O. The management of acute complications is symptomatic. The management of chronic complications is based on vitamin B12 supplementation. The best biomarker of chronic N2O exposure is the elevation of the plasmatic level of methylmalonic acid. In all cases of recreational misuses, addiction treatment is necessary to prevent complications or their worsening by providing information in order to stop consumption.

[Treatment of tremor by stereotactic surgery]. / Traitement du tremblement par chirurgie stéréotaxique.

Thalamotomy in the ventrolateral thalamic nucleus is a common treatment of severe parkinsonian or essential tremor. Although results are often satisfactory, complications may occur and alter the success of the operation. High frequency stimulation of the target before thalamotomy leads to transitory abolition of the tremor. Therefore, a chronic stimulation device was developed and its use produced results similar to those of thalamotomy for parkinsonian tremor. Unwanted side-effect can be reduced by changing the parameters of the stimulation. Improvements in multiple sclerosis and post-traumatic tremors may be expected. We present a review of the indications and results of both technics.