[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.

[Differential diagnosis of status epilepticus in intensive care: about one case of sporadic Creutzfeldt-Jakob]. / Diagnostic différentiel d'un état de mal épileptique en réanimation: à propos d'un cas de Creutzfeldt-Jakob sporadique.

A 78-year-old man was admitted in the intensive care unit for epilepsy seizure (tonic-clonic seizure). Since three months, his wife reports motor dysfunction (weakness) and since two weeks, rapidly progressive changes in cognition (apraxia, akinetic mutism). The diagnosis of probable sporadic Creutzfeldt-Jakob on the basis of clinical, EEG and MRI lesions was made. Refining diagnostic criteria is probably needed, including the usefulness of repeated MRI with FLAIR and diffusion-weighted imaging.

[Medico-economic assessment of the Pontoise Hospital stroke unit]. / Évaluation médico-économique de l'unité neurovasculaire du centre hospitalier de Pontoise.

INTRODUCTION: Annually, approximately 120,000 people in France have a stroke. Various controlled studies have pointed out the benefits of treatment in a stroke unit (SU). The objective of this study was to evaluate, from a medical point of view, the economic impact of the Pontoise Hospital SU. PATIENTS AND METHODS: Based on the national cost study (NCS [étude nationale des coûts: ENC]) we analyzed data of five diagnosis related groups (DRG) which have a principle diagnosis in relation with stroke. This work was limited to strokes and transient ischemic events in adults and excluded sub-arachnoid hemorrhage. Medical and economic parameters were collected over the period from January to October 2006 and compared with those of the same period in 2005, that is to say before the opening of the SU. RESULTS: Three hundred and twenty-three hospital stays occurred between January 1st and October 31st, 2006 and 216 during the same time period before the opening of the SU, an increase of approximately 50% of all stroke-related admissions in our hospital. The number of stays carried out in the neurology unit increased by 29%. There was no significant difference between the two periods regarding age (median 69 versus 70 years) and sex- ratio. Average length of stay (ALS) was the same (9 days). There were no significant differences concerning the death rate (5.6% versus 6.2%) and that of discharge to home (44.6% versus 44.4%). The cost by stay in 2006 was 3534 euros [median; min 664-max 57,542] versus 3541 euros in 2005 [681-35,149] (p=0.57). Analysis by DRG highlighted an increase in the cost for serious strokes, cerebral infarctions and hemorrhages. For transitory ischemic events, the cost and the ALS decreased. CONCLUSION: After the opening of the SU, there was an increase in the activity without an increase in the total cost. This could be related in part to the limited means allocated to the stroke unit at its opening (in particular medical staff). The NCS can be used to evaluate the activity of a stroke unit. This work could be completed on a larger number of units or in several units of different size.

Transient decrease of water diffusion in Wernicke's encephalopathy.

We report water diffusion abnormalities in periventricular areas in a patient with Wernicke's encephalopathy. The reduction in diffusion disappeared after 2 weeks of treatment with intravenous thiamine. We suggest that the restricted mobility of cerebral water is related to inflammatory lesions.

Cerebral Venous Thrombosis.

Cerebral venous thrombosis is a rare disorder with highly variable and nonspecific clinical presentations. For these reasons, specific treatment should be given only when the diagnosis has been firmly established. Etiologic diagnosis should begin in the emergency department to identify underlying conditions that require specific treatment. The mainstay of treatment is anticoagulation with heparin, even in the case of cerebral hemorrhage, followed as soon as possible by oral anticoagulant administration. The optimal duration of oral anticoagulation has not been established. By analogy with systemic venous thrombosis, it should be prolonged 3 to 6 months. When a high risk of recurrence is present, treatment should be continued until the risk disappears. In contrast to arterial stroke, complete recovery of prolonged or severe neurologic deficit is possible, justifying initiation of anticoagulation even when the clinical situation seems desperate. For the same reason, aggressive treatment of intracranial hypertension and seizures or status epilepticus is warranted. Screening for extraneurologic venous thrombosis should be done by means of clinical examination and, if necessary, specific imaging procedures. Local thrombolysis is not yet of proven efficacy and safety. It can be used in patients with clinical worsening related to documented extension of the venous thrombosis despite anticoagulation and in the absence of cerebral hematoma. Surgical treatment is limited to external ventricular drainage and suboccipital craniotomy in the very rare cases of cerebellar vein thrombosis with edematous cerebellar infarct.

[Aspirin and cerebral ischemic accidents]. / Aspirine et accidents ischémiques cérébraux.

At the acute phase of cerebral infarction, two recent large studies found that the use of aspirin reduces both mortality and the risk of the recurrence of stroke. In primary prevention, aspirin nearly halves the risk of myocardial infarction but does not reduce that of stroke. Concerning the secondary prevention of atherothrombotic brain infarcts, aspirin has been the most extensively studied drug, and is efficient between 50 mg and 1.3 g. In spite of the efficacy of other antiplatelets in this indication--ticlopidine (500 mg), clopidogrel (75 mg) and dipyridamole (400 mg)--aspirin remains the most cost-effective, doses between 100 and 300 mg being the most widely used. Cardiac diseases with a high embolic risk require the use of oral anticoagulation. In nonvalvular atrial fibrillation, the choice of antithrombotic drugs depends on risk stratification: oral anticoagulants are indicated in high-risk subjects, whereas aspirin is recommended in low-risk subjects and when oral anticoagulants are contraindicated. Studies with associations of aspirin and other antiplatelets are required to increase the yield of this medication in high-risk subjects, in parallel with efforts to detect and to treat the vascular risk factors.

[Anti-platelet and anticoagulant therapy in acute cerebral ischemia]. / Antiplaquettaires et anticoagulants dans l'ischémie cérébrale aiguë.

Therapeutical trials in the acute phase of stroke have showed a moderate benefit of administration of aspirin in prevention of death or recurrent cerebral events. This benefit was obtained despite a small increase in systemic and cerebral haemorrhages. Heparin used at high dosage, without any control of coagulation test, induces an excess of cerebral and systemic haemorrhage which overset its benefit in prevention of recurrent cerebral events. Similar results have been observed with heparinoid and nadroparine used at high dosage. The only benefit of anticoagulation is the prevention of total and fatal pulmonary embolism which has been observed in all recent studies. The antithrombotic treatment which offers the best ratio benefit-risk in the acute phase of stroke is aspirin at a minimum dosage of 160 mg by day and, if risk factors are present, heparin at an adequate dosage to prevent venous thrombo-embolism. Explicative studies are required to explore the potential benefit of heparin in patients with a high risk of recurrent cerebral ischemic events.

[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.