[Pathophysiological and diagnostic aspects of Guillain-Barré syndrome]. / Syndrome de Guillain-Barré : physiopathologie et aspects diagnostiques.

Guillain-Barré syndrome (GBS) is the most common cause of acute neuropathy. It usually onset with a rapidly progressive ascending bilateral weakness with sensory disturbances, and patients may require intensive treatment and close monitoring as about 30% have a respiratory muscle weakness and about 10% have autonomic dysfunction. The diagnosis of GBS is based on clinical history and examination. Complementary examinations are performed to rule out a differential diagnosis and to secondarily confirm the diagnosis. GBS is usually preceded by an infectious event in ≈ 2/3 of cases. Infection leads to an immune response directed against carbohydrate antigens located on the infectious agent and the formation of anti-ganglioside antibodies. By molecular mimicry, these antibodies can target structurally similar carbohydrates found on host's nerves. Their binding results in nerve conduction failure or/and demyelination which can lead to axonal loss. Some anti-ganglioside antibodies are associated with particular variants of GBS: the Miller-Fisher syndrome, facial diplegia and paresthesias, the pharyngo-cervico-brachial variant, the paraparetic variant, and the Bickerstaff brainstem encephalitis. Their semiological differences might be explained by a distinct expression of gangliosides among nerves. The aim of this review is to present pathophysiological aspects and the diagnostic approach of GBS and its variants.

Toxic-metabolic encephalopathy in adults: Critical discussion and pragmatical diagnostic approach.

Toxic-metabolic encephalopathy (TME) results from an acute cerebral dysfunction due to different metabolic disturbances including medications or illicit-drugs. It can lead to altered consciousness, going from delirium to coma, which may require intensive care and invasive mechanical ventilation. Even if it is a life-threatening condition, TME might have an excellent prognosis if its etiology is rapidly identified and treated adequately. This review summarizes the main etiologies, their differential diagnosis, and diagnostic strategy and management of TME with a critical discussion on the definition of TME.

Home-based exercise in autoimmune myasthenia gravis: A randomized controlled trial.

The tolerance of exercise and its effects on quality of life in myasthenia gravis are not currently backed up by strong evidence. The aim of this study was to determine whether exercise as an adjunct therapy is well tolerated and can improve health-related quality of life (HRQoL) in stabilized, generalized autoimmune myasthenia gravis (gMG). We conducted a parallel-group, multi-center prospective RCT using computer-generated block randomization. Adults with stabilized, gMG, and no contra-indication to exercise, were eligible. Participants received usual care alone or usual care and exercise. The exercise intervention consisted of 3-weekly 40 min sessions of an unsupervised, moderate-intensity home rowing program over 3 months. The primary endpoint was the change in HRQoL from randomization to post-intervention. Assessor-blinded secondary endpoints were exercise tolerance and effects on clinical, psychological and immunological status. Of 138 patients screened between October 2014 and July 2017, 45 were randomly assigned to exercise (n = 23) or usual care (n = 20). Although exercise was well tolerated, the intention-to-treat analysis revealed no evidence of improved HRQoL compared to usual care (MGQOL-15-F; mean adjusted between-groups difference of -0.8 points, 95%CI -5.4 to 3.7). Two patients hospitalized for MG exacerbation were from the usual care group.

COVID-19-related encephalopathy: a case series with brain FDG-positron-emission tomography/computed tomography findings.

AIM: The aim of this paper is to describe the clinical features of COVID-19-related encephalopathy and their metabolic correlates using brain 2-desoxy-2-fluoro-D-glucose (FDG)-positron-emission tomography (PET)/computed tomography (CT) imaging. BACKGROUND AND PURPOSE: A variety of neurological manifestations have been reported in association with COVID-19. COVID-19-related encephalopathy has seldom been reported and studied. METHODS: We report four cases of COVID-19-related encephalopathy. The diagnosis was made in patients with confirmed COVID-19 who presented with new-onset cognitive disturbances, central focal neurological signs, or seizures. All patients underwent cognitive screening, brain magnetic resonance imaging (MRI), lumbar puncture, and brain 2-desoxy-2-fluoro-D-glucose (FDG)-positron-emission tomography (PET)/computed tomography (CT) (FDG-PET/CT). RESULTS: The four patients were aged 60 years or older, and presented with various degrees of cognitive impairment, with predominant frontal lobe impairment. Two patients presented with cerebellar syndrome, one patient had myoclonus, one had psychiatric manifestations, and one had status epilepticus. The delay between first COVID-19 symptoms and onset of neurological symptoms was between 0 and 12 days. None of the patients had MRI features of encephalitis nor significant cerebrospinal fluid (CSF) abnormalities. SARS-CoV-2 RT-PCR in the CSF was negative for all patients. All patients presented with a consistent brain FDG-PET/CT pattern of abnormalities, namely frontal hypometabolism and cerebellar hypermetabolism. All patients improved after immunotherapy. CONCLUSIONS: Despite varied clinical presentations, all patients presented with a consistent FDG-PET pattern, which may reflect an immune mechanism.

Correction to: Functional outcomes in adult patients with herpes simplex encephalitis admitted to the ICU: a multicenter cohort study.

The original article unfortunately contained a mistake. Due to technical problems the study group was not tagged correctly. Please find the correct tagging down below. We apologize for the mistake.

Functional outcomes in adult patients with herpes simplex encephalitis admitted to the ICU: a multicenter cohort study.

PURPOSE: We aimed to study the association of body temperature and other admission factors with outcomes of herpes simplex encephalitis (HSE) adult patients requiring ICU admission. METHODS: We conducted a retrospective multicenter study on patients diagnosed with HSE in 47 ICUs in France, between 2007 and 2017. Fever was defined as a body temperature higher or equal to 38.3 °C. Multivariate logistic regression analysis was used to identify factors associated with poor outcome at 90 days, defined by a score of 3-6 (indicating moderate-to-severe disability or death) on the modified Rankin scale. RESULTS: Overall, 259 patients with a score on the Glasgow coma scale of 9 (6-12) and a body temperature of 38.7 (38.1-39.2) °C at admission were studied. At 90 days, 185 (71%) patients had a poor outcome, including 44 (17%) deaths. After adjusting for age, fever (OR = 2.21; 95% CI 1.18-4.16), mechanical ventilation (OR = 2.21; 95% CI 1.21-4.03), and MRI brain lesions > 3 lobes (OR = 3.04; 95% CI 1.35-6.81) were independently associated with poor outcome. By contrast, a direct ICU admission, as compared to initial admission to the hospital wards (i.e., indirect ICU admission), was protective (OR = 0.52; 95% CI 0.28-0.95). Sensitivity analyses performed after adjustment for functional status before admission and reason for ICU admission yielded similar results. CONCLUSIONS: In HSE adult patients requiring ICU admission, several admission factors are associated with an increased risk of poor functional outcome. The identification of potentially modifiable factors, namely, elevated admission body temperature and indirect ICU admission, provides an opportunity for testing further intervention strategies.

Posterior reversible encephalopathy syndrome (PRES) and hypomagnesemia: A frequent association?

Posterior reversible encephalopathy syndrome (PRES) is a serious neurological condition encountered in various medical fields. Pathophysiological factor(s) common to PRES cases of apparently unrelated etiologies are yet to be found. Based on the hypothesis that hypomagnesemia might participate in the cascade leading to PRES, our study sought to verify whether hypomagnesemia is frequently associated with PRES regardless of etiology. From a retrospective study of a cohort of 57 patients presenting with PRES of different etiologies, presented here are the findings of 19 patients with available serum magnesium levels (SMLs) during PRES. In the acute phase of PRES, hypomagnesemia was present in all 19 patients in spite of differences in etiology (including immunosuppressive drugs, hypertensive encephalopathy, eclampsia, systemic lupus erythematosus, iatrogenic etiology and unknown). SMLs were within normal ranges prior to PRES and below normal ranges during the first 48h of PRES, with a significant decrease in SMLs during the acute phase. In this retrospective study, constant hypomagnesemia was observed during the acute phase of PRES regardless of its etiology. These results now require larger studies to assess the particular importance of acute hypomagnesemia in PRES and especially the possible need to treat PRES with magnesium sulfate.

Sporadic Creutzfeldt-Jakob disease mimicking nonconvulsive status epilepticus.

BACKGROUND: Nonconvulsive status epilepticus (NCSE) in patients with confusion may be difficult to distinguish from nonepileptic (metabolic/toxic, postanoxic, and spongiform) encephalopathies. This study aimed to describe the misleading presentation of patients with sporadic Creutzfeldt-Jakob disease (sCJD) who were initially diagnosed with a refractory NCSE (rNCSE). METHODS: We retrospectively reviewed the clinical characteristics, EEG records, brain MRI scans, 14-3-3 protein detection in CSF, genotype of the prion protein gene, and neuropathologic data of patients referred to our neurologic intensive care unit (NICU) with this presentation. RESULTS: Ten patients with a final diagnosis of definite (n = 7) or probable (n = 3) sCJD were referred to our NICU with an initial diagnosis of rNCSE. Reanalysis of the EEG ruled out ictal rhythmic activities, but showed diffuse, periodic, or semiperiodic sharp-wave complexes (PSWC) with short period. PSWC were briefly attenuated by auditory (n = 5) or painful (n = 3) stimuli and by IV injection of antiepileptic drugs (n = 5) but without clinical improvement. In addition, PSWC showed fluctuations according to the vigilance level (n = 5). Brain MRI showed hyperintensities in basal ganglia (n = 9/10) and in cortical areas (n = 7/10). 14-3-3 Protein was detected in CSF (n = 10). Only 2 sCJD subtypes were found (MM1 5/7, MV1 2/7). CONCLUSIONS: This series of patients suggests that sporadic Creutzfeldt-Jakob disease should be considered as a differential diagnosis, rather than as a cause, of apparent refractory nonconvulsive status epilepticus. Criteria for nonconvulsive status epilepticus diagnosis should rely on careful examination of both EEG parameters and clinical state so that aggressive, unnecessary treatments can be avoided.

[Management of convulsive status epilepticus: therapeutic strategies]. / Prise en charge de l'état de mal tonicoclonique généralisé : stratégies thérapeutiques.

Increasing duration of generalized tonic-clonic status epilepticus increases the risk of neuronal damage and systemic complications. It is also a recognized contributing factor to drug resistance. The most indispensable quality an anticonvulsive medication is expected to have in this situation is therefore a rapid therapeutic effect, achieved without severe depressive, neurological, cardiovascular or respiratory side effects. The anticonvulsive strategy proposed here takes into account these prerequisites, as well as previously published research findings which remain limited on a number of aspects. The duration of the convulsions before medication must be taken into account when deciding on the initial treatment. If this is less than 30 min, a single drug regimen with benzodiazepine would be appropriate and sufficient initially. If lorazepam, which is unavailable in France, cannot be used, the pharmacokinetically similar clonazepam should be preferred. Beyond 30 min, a combination of benzodiazepine and an anticonvulsive with long-lasting effects -phenobarbital or fosphenytoin- is indicated. The choice between these two latter drugs depends on their respective contraindications and the circumstances surrounding the occurrence of the status epilepticus. The persistence of seizures beyond 20 min after beginning the phenobarbital infusion or 30 min after starting fosphenytoin signals a failure of the initial treatment and requires the immediate introduction of a second line of therapy. This may be an anticonvulsive with long-lasting effects providing the convulsions have been present for less than an hour, there is no suspicion of an acute cerebral lesion and there is no associated systemic factor of cerebral aggression. If not, the employment of anesthetic medication is immediately required.

[The French version of the FOUR score: A new coma score]. / Le FOUR score en français, un nouveau score d'évaluation de la profondeur du coma.

BACKGROUND: Comatose state is a major cause for admission to the intensive care unit. The most commonly used assessment score is the Glasgow coma scale (GCS). Although widely accepted, this score has several limitations. Recently, the full outline of unresponsiveness score (FOUR) has been validated and tested as reliable as the GCS. METHODS: We translated this score in French and tested its reliability in a neurological critical care unit. This study included eight critical care patients and eight intensive care patients. The patients were successively evaluated by two neurologists, four experienced nurses and five inexperienced nurses; a total of 176 evaluations were performed. The weighted kappa (kappa(W)) was used to determine the reliability of the evaluation for both the FOUR score and the GCS. RESULTS: The mean age of the patients was 62 years. The interobserver reliability of the French version of the FOUR score was high (kappa(W)=0.86; IC 95%: 0.83-0.89) comparable to that of the GCS (kappa(W)=0.85; IC 95%: 0.82-0.88). CONCLUSION: The French version of the FOUR score has an excellent interobserver reliability. This score is easy to perform and well accepted, only requiring simple and short training.

[Non specific treatment of status epilepticus]. / Prise en charge non spécifique de l'état de mal épileptique convulsif.

The systemic consequences of status epilepticus occur in two stages: the first stage is a hyperadrenergic period (high blood pressure, tachycardia, arrhythmia, hyperventilation, hypermetabolism, hyperthermia), the second stage a collapsus period, sometimes with acute circulatory failure, and hypoxemia. Symptomatic resuscitation aimed at restoring vital functions should be undertaken. Resuscitation must be started immediately before hospital transfer, by a trained emergency team. Respiratory care includes at least oxygen intake, but it can also require oral intubation (crash induction) and mechanical ventilation. The arterial blood gas objectives are SaO(2)> or =95%, and 35mmHg< or =PaCO(2)< or =40mmHg. Fluid and electrolyte care includes intravenous infusion of normal saline, with control of sodium and calcium levels as well as blood pH within normal limits. Heart rate and blood pressure must be monitored. Mean blood pressure must be kept between 70 and 90mmHg, first by means of plasma volume expansion, and then norepinephrine if necessary. Hyperthermia must be corrected to prevent further neuronal damage. Cerebromeningeal sepsis should be ruled out. Capillary glucose (most often elevated) must be corrected using a pre-established insulin infusion algorithm. Rhabdomyolysis is rare, but can result in hyperkaliemia, acidosis, and acute renal failure. In case of associated intracranial hypertension (traumatic, vascular or infectious injury), status epilepticus is considered as a secondary insult for the brain, that can worsen neuronal damage. Numerous compounds have experimental neuroprotective properties, but none have proven significant efficacy in clinical conditions. Nevertheless, convulsion cessation is considered as a neuroprotective measure.

Vivid dreams, hallucinations, psychosis and REM sleep in Guillain-Barré syndrome.

We conducted a prospective controlled study of the clinical and biological determinants of the mental status abnormalities in 139 patients with Guillain-Barré syndrome (GBS) and 55 patients without GBS placed in the intensive care unit (ICU controls). There were mental status changes in 31% of GBS patients and in 16% of controls (odds ratio = 2.3; P = 0.04). In GBS patients, they included vivid dreams (19%), illusions (30%, including an illusory body tilt), hallucinations (60%, mainly visual) and delusions (70%, mostly paranoid). They appeared a median 9 days after disease onset (range 1-40 days, during the progression or the plateau of the disease), and lasted a median 8 days. Seven (16%) patients experienced the symptoms before their admission to the ICU. Hallucinations were frequently hypnagogic, occurring as soon as the patients closed their eyes. Autonomic dysfunction, assisted ventilation and high CSF protein levels were significant risk factors for abnormal mental status in GBS patients. CSF hypocretin-1 (a hypothalamic neuropeptide deficient in narcolepsy) levels, measured in 20 patients, were lower in GBS patients with hallucinations (555 +/- 132 pg/ml) than in those without (664 +/- 71 pg/ml, P = 0.03). Since the mental status abnormalities had dream-like aspects, we examined their association with rapid eye movement sleep (REM sleep) using continuous sleep monitoring in 13 GBS patients with (n = 7) and without (n = 6) hallucinations and 6 tetraplegic ICU controls without hallucinations. Although sleep was short and fragmented in all groups, REM sleep latency was shorter in GBS patients with hallucinations (56 +/- 115 min) than in GBS patients without hallucinations (153 +/- 130 min) and in controls (207 +/- 179 min, P < 0.05). In addition, sleep structure was highly abnormal in hallucinators, with sleep onset in REM sleep periods (83%), abnormal eye movements during non-REM sleep (57%), high percentages of REM sleep without atonia (92 +/- 22%), REM sleep behaviour disorders and autonomic dysfunction (100%), reminiscent of a status dissociatus. The sleep abnormalities, that were almost absent in non-hallucinated GBS patients, were not exclusively related to ICU conditions, since they also appeared out of ICU, and were reversible, disappearing when the mental status abnormalities vanished while the patients were still in ICU. In conclusion, the mental status abnormalities experienced by GBS patients are different from the ICU delirium, are strongly associated with autonomic dysfunction, severe forms of the disease and possibly with a transitory hypocretin-1 transmission decrease. Sleep studies suggest that mental status abnormalities are wakeful dreams caused by a sleep and dream-associated disorder (status dissociatus).

[Physiopathology of ALS: therapeutic approach]. / Physiopathologie de la sclérose latérale amyotrophique: approches thérapeutiques.

The finding in 1993 of a mutation of the copper zinc super oxyde dismutase (SOD1) provides a major breakthrough in the understanding of the etiopathogenic mechanism of amyotrophic lateral sclerosis. Various mechanisms are commonly implied in the motor neurons degeneration. Excitotoxicity and calcium metabolism abnormalities are one of the most frequently confirmed hypotheses. It allowed proposing riluzole which remains the only one drug proved to be active in the disease. The role of growth factors remains controversial and all therapeutic trials performed with these molecules remained negative. Oxidative stress abnormalities are demonstrated by number of studies but their direct therapeutic application remains to be demonstrated. Apoptosis and the role of mitochondria has been definitely confirmed and open a new therapeutic avenue for the next few years.

Decisional role of the dorsolateral prefrontal cortex in ocular motor behaviour.

Three patients with a unilateral cortical lesion affecting the dorsolateral prefrontal cortex (DLPFC), i.e. Brodmann area 46, were tested using different paradigms of reflexive saccades (gap and overlap tasks), intentional saccades (antisaccades, memory-guided and predictive saccades) and smooth pursuit movements. Visually guided saccades with gap and overlap, latency of correct antisaccades and memory-guided saccades and the gain of smooth pursuit were normal, compared with controls. These results confirm our anatomical data showing that the adjacent frontal eye field (FEF) was unimpaired in these patients. The specific pattern of abnormalities after a unilateral DLPFC lesion, compared with that of the FEF lesions previously reported, consists mainly of: (i) a bilateral increase in the percentage of errors in the antisaccade task (misdirected reflexive saccades); (ii) a bilateral increase in the variable error in amplitude, without significant decrease in the gain, in the memory-guided saccade task; and (iii) a bilateral decrease in the percentage of anticipatory saccades in the predictive task. Taken together, these results suggest that the DLPFC plays a crucial role in the decisional processes, preparing saccades by inhibiting unwanted reflexive saccades (inhibition), maintaining memorized information for ongoing intentional saccades (short-term spatial memory) or facilitating anticipatory saccades (prediction), depending upon current external environmental and internal circumstances.

Concurrent excitatory and inhibitory effects of high frequency stimulation: an oculomotor study.

OBJECTIVE: To describe a reversible neurological condition resembling a crossed midbrain syndrome resulting from high frequency stimulation (HFS) in the midbrain. METHODS: Postoperative evaluation of quadripolar electrodes implanted in the area of the subthalamic nucleus of 25 patients with Parkinson's disease (PD) successfully treated by HFS. RESULTS: Four of the 25 patients experienced reversible acute diplopia, with dystonic posture and tremor in the contralateral upper limb when the white matter between the red nucleus and the substantia nigra was stimulated. The motor signs resembled those caused by lesions of the red nucleus. The ipsilateral resting eye position was "in and down" (three patients) or "in" (one patient). Enophthalmos was seen. Abduction was impaired and vertical eye movements were limited, but adduction was spared. The movements of the controlateral eye were normal. The ocular signs could be best explained by sustained hyperactivity of the extrinsic oculomotor nerve. Simultaneous tonic contraction of the superior rectus, the inferior rectus, and inferior oblique may cause the enophthalmos and partial limitation of upward and downward eye movements. Antagonist tonic contraction of the ipsilateral medial rectus severely impairs abduction. CONCLUSION: This crossed midbrain syndrome, possibly resulting from simultaneous activation of oculomotor nerve and lesion-like inhibition of the red nucleus suggests that high frequency stimulation has opposite effects on grey and white matter.