Prospective study of the additional benefit of plexus magnetic resonance imaging in the diagnosis of chronic inflammatory demyelinating polyneuropathy.

BACKGROUND AND PURPOSE: Hypertrophy/signal hyperintensity and/or gadolinium enhancement of plexus structures on magnetic resonance imaging (MRI) are observed in two-thirds of cases of typical chronic inflammatory demyelinating polyneuropathy (CIDP). The objective of our study was to determine the additional benefit of plexus MRI in patients referred to tertiary centers with baseline clinical and electrophysiological characteristics suggestive of typical or atypical CIDP. METHODS: A total of 28 consecutive patients with initial suspicion of CIDP were recruited in nine centers and followed for 2 years. Plexus MRI data from the initial assessment were reviewed centrally. Physicians blinded to the plexus MRI findings established the final diagnosis (CIDP or neuropathy of another cause). The proportion of patients with abnormal MRI was analyzed in each group. RESULTS: Chronic inflammatory demyelinating polyneuropathy was confirmed in 14 patients (50%), as were sensorimotor CIDP (n = 6), chronic immune sensory polyradiculoneuropathy (n = 2), motor CIDP (n = 1) and multifocal acquired demyelinating sensory and motor neuropathy (n = 5). A total of 37 plexus MRIs were performed (17 brachial, 19 lumbosacral and 8 in both localizations). MRI was abnormal in 5/37 patients (14%), all of whom were subsequently diagnosed with CIDP [5/14(36%)], after an atypical baseline presentation. With plexus MRI results masked, non-invasive procedures confirmed the diagnosis of CIDP in all but one patient [1/14 (7%)]. Knowledge of the abnormal MRI findings in the latter could have prevented nerve biopsy being performed. CONCLUSION: Systematic plexus MRI in patients with initially suspected CIDP provides little additional benefit in confirming the diagnosis of CIDP.

[Bell's palsy]. / La paralysie faciale périphérique a frigore.

Idiopathic peripheral facial palsy, also named Bell's palsy, is the most common cause of peripheral facial palsy in adults. Although it is considered as a benign condition, its social and psychological impact can be dramatic, especially in the case of incomplete recovery. The main pathophysiological hypothesis is the reactivation of HSV 1 virus in the geniculate ganglia, leading to nerve edema and its compression through the petrosal bone. Patients experience an acute (less than 24 hours) motor deficit involving ipsilateral muscles of the upper and lower face and reaching its peak within the first three days. Frequently, symptoms are preceded or accompanied by retro-auricular pain and/or ipsilateral face numbness. Diagnosis is usually clinical but one should look for negative signs to eliminate central facial palsy or peripheral facial palsy secondary to infectious, neoplastic or autoimmune diseases. About 75% of the patients will experience spontaneous full recovery, this rate can be improved with oral corticotherapy when introduced within the first 72 hours. To date, no benefit has been demonstrated by adding an antiviral treatment. Hemifacial spasms (involuntary muscles contractions of the hemiface) or syncinesia (involuntary muscles contractions elicited by voluntary ones, due to aberrant reinnervation) may complicate the disease's course. Electroneuromyography can be useful at different stages: it can first reveal the early conduction bloc, then estimate the axonal loss, then bring evidence of the reinnervation process and, lastly, help for the diagnosis of complications.

Good prognosis of postpartum lower limb sensorimotor deficit: a combined clinical, electrophysiological, and radiological follow-up.

Postpartum lower limb motor and/or sensory deficit is an uncommon obstetrical complication. We aimed to identify its incidence, etiology, and precipitating factors, as well as the neurological prognosis by retrospectively analyzing the successive neurological evaluations, electrophysiological, and MRI data from all the consecutive patients with postpartum motor and/or sensory deficits of the lower limbs referred from the Lariboisière Obstetrical Department to the Lariboisière Neurophysiology Department, from January 2012 to June 2016, as well as data concerning labor and morphological characteristics of mother and baby. Thirteen patients (0.11% of the parturient women in the Lariboisière hospital) were included. Eight (62%) had lumbosacral plexopathy. Symptoms followed a first vaginal delivery in 10/13 patients (77%), in patients who were mostly overweight (mean patient BMI before pregnancy 25.6 ± 3.2 kg/m2). Labor duration was slightly longer than average (mean labor duration 8.9 ± 2.9 h). No other potentially precipitating factor was identified. Recovery was good in all patients, 7/11 (64%) made a rapid full recovery (mean recovery time 5 ± 2.5 weeks excluding one patient who had a normal neurological examination at 2 weeks but still complained of foot weakness that fully recovered in 1 year), and a minority (4/11, 36%) still complained of minor symptoms at time of follow-up, but showed marked improvement. New mothers presenting postpartum lower limb nerve injury should, therefore, be reassured.

Plasma exchanges for severe acute neurological deterioration in patients with IgM anti-myelin-associated glycoprotein (anti-MAG) neuropathy.

Monoclonal IgM anti-myelin-associated glycoprotein (MAG) antibody-related peripheral neuropathy (anti-MAG neuropathy) is predominantly a demyelinating sensory neuropathy with ataxia and distal paresthesia. The clinical course of anti-MAG neuropathy is usually slowly progressive making difficult the identification of clear criteria to start a specific treatment. Although no consensus treatment is yet available, a rituximab-based regimen targeting the B-cell clone producing the monoclonal IgM may be proposed, alone or in combination with alkylating agents or purine analogs. However, in some rare cases, an acute and severe neurological deterioration can occur in few days leading to a rapid loss of autonomy. In these cases, a treatment rapidly removing the monoclonal IgM from the circulation might be useful before initiating a specific therapy. We report successful treatment with plasma exchanges (PE) in four patients presenting with acute neurological deterioration. PE allowed a dramatic and rapid neurological improvement in all patients. PE are safe and may be useful at the initial management of these cases of anti-MAG neuropathy.

[Where have the neuronal stem cells of the subependymal zone gone in human beings?]. / Ou sont donc passées les cellules-souches neuronales de la couche sous-ependymaire chez l'etre humain?

Stem cells are characterized by their ability for self-renewal (allowing them to be present throughout the entire life of the organism) and their ability to give rise to differentiated cells belong to one or more lineages. The strict definition of these cells is however still a matter of debate. There is new experimental evidence (including in human beings) that stem cells are present within the brain and may give rise to neurons. Ependymal cells have been proposed to play such a role. In fact, subependymal cells expressing GFAP would be more likely candidates. Such cells are observed in the brain of human beings. They are able to differentiate into neurons in vitro but such potential appears to be repressed in vivo.

[From bench to bedside: should we believe in the efficacy of stem cells in cerebral ischaemia?]. / Du laboratoire au lit du patient: faut-il croire à l'efficacité des "cellules souches" Dans l'ischemie cérébrale?

Stroke is the third cause of mortality and the leading cause of morbidity in industrialized countries. At the present time, ischaemic stroke is treated at the acute phase by thrombolysis with a recombinant of the tissular-plasminogen activator, which must be administered within the first 3 hours. Cell therapy, while using the self-renewal and differentiation potentials of stem cells, brings new hope for the long-term care of ischaemic stroke. Animal studies show that stem cells improve functional deficit without reduction of infarct volume and with very rare differentiation of the stem cell. These experimental studies suggest that stem cells would support cerebral plasticity via growth factor production and stimulation of endogenous mechanisms of local repair. Assessment of effectiveness and safety in the use of stem cells in cerebral ischaemia still require thorough investigation before clinical trials in humans can be developed.

Adaptive common carotid arteries remodeling after unilateral internal carotid artery occlusion in adult patients.

OBJECTIVE: This study was undertaken in human adults to examine modifications in common carotid internal diameter (ID), intima-media thickness (IMT), cross-sectional area (CSA) and wall shear stress (WSS) occurring both on the ipsilateral side of an internal carotid artery (ICA) occlusion and on the non-occluded contralateral side. METHODS: Seventeen patients with unilateral ICA occlusion had repeated echo-Doppler examinations during 1 year and were compared to 12 volunteers with control non-occluded common carotid arteries (CCA). RESULTS: The cause of ICA occlusion was atherosclerosis in nine patients, dissection in five, and undetermined in three. The results showed a significant reduction in ID on the occluded side (5.15 +/- 0.30 mm) compared with the non-occluded side (5.96 +/- 0.20 mm, P < 0.05) and with control arteries (5.55 +/- 0.10, P < 0.05). A significant reduction in blood flow was observed on the occluded side (404 +/- 58 ml/min) compared with the non-occluded side (703 +/- 51 ml/min, P < 0.0001) and with controls (567 +/- 27 ml/min, P < 0.0001). Wall cross-sectional area was found to be positively correlated to blood flow (r = 0.35, P < 0.01), without any significant difference in mean CSA between both sides. Interestingly, wall shear stress values were identical on both sides whatever the cause of ICA occlusion, and did not differ from those in controls. CONCLUSIONS: Our results suggest that in humans, the internal diameter of the common carotid artery decreases in response to chronic decrease in blood flow, in order to maintain a constant wall shear stress even in pathological arteries.

[Management of neuropathic pain]. / Prise en charge de la douleur neuropathique.

Neuropathic pain is often underestimated and not adequately treated. The DN4 scale is very useful for its identification since it will benefit from pharmacological and non-pharmacological specific alternative care. The pathophysiological mechanisms involve the hyperexcitability of nociceptive pathways or decreased inhibitory descending controls that will be the target of pharmacological treatments. Frontline molecules are antidepressants (tricyclics and mixed serotonin and norepinephrine reuptake inhibitors) and antiepileptics (α2δ calcium channel inhibitors). However, these drugs will only have a partial efficacy on pain. The therapeutic strategy is based on reasonable goals, starting with a monotherapy adapted to the patient's symptoms and comorbidities and increased step by step. Patient compliance to contract is essential and requires clear and complete information. The impact on profession, social and family integration should rapidly be taken into account. In case of inefficiency, a change of the first-line treatment or an association could be considered. Some indications justify a specific therapy. Patients with resistant chronic pain should be sent to a specialized centre. New drugs are being studied and non-pharmacological support must be evaluated.

Tele-transmission of EEG recordings.

EEG recordings can be sent for remote interpretation. This article aims to define the tele-EEG procedures and technical guidelines. Tele-EEG is a complete medical act that needs to be carried out with the same quality requirements as a local one in terms of indications, formulation of the medical request and medical interpretation. It adheres to the same quality requirements for its human resources and materials. It must be part of a medical organization (technical and medical network) and follow all rules and guidelines of good medical practices. The financial model of this organization must include costs related to performing the EEG recording, operating and maintenance of the tele-EEG network and medical fees of the physician interpreting the EEG recording. Implementing this organization must be detailed in a convention between all parties involved: physicians, management of the healthcare structure, and the company providing the tele-EEG service. This convention will set rules for network operation and finance, and also the continuous training of all staff members. The tele-EEG system must respect all rules for safety and confidentiality, and ensure the traceability and storing of all requests and reports. Under these conditions, tele-EEG can optimize the use of human resources and competencies in its zone of utilization and enhance the organization of care management.

Somatosensory evoked potentials in the assessment of peripheral neuropathies: Commented results of a survey among French-speaking practitioners and recommendations for practice.

BACKGROUND: Somatosensory evoked potentials (SSEPs) are increasingly performed for the assessment of peripheral neuropathies, but no practical guidelines have yet been established in this specific application. STUDY AIM: To determine the relevant indication criteria and optimal technical parameters for SSEP recording in peripheral neuropathy investigation. METHODS: A survey was conducted among the French-speaking practitioners with experience of SSEP recording in the context of peripheral neuropathies. The results of the survey were analyzed and discussed to provide recommendations for practice. RESULTS: SSEPs appear to be a second-line test when electroneuromyographic investigation is not sufficiently conclusive, providing complementary and valuable information on central and proximal peripheral conduction in the somatosensory pathways. CONCLUSIONS: Guidelines for a standardized recording protocol, including the various parameters to be measured, are proposed. CLINICAL RELEVANCE: We hope that these proposals will help to recognize the value of this technique in peripheral neuropathy assessment in clinical practice.

Thrombotic carotid megabulb: fibromuscular dysplasia, septae, and ischemic stroke.

The proximal internal carotid artery is most commonly spared in cerebral fibromuscular dysplasia. The authors report the cases of three young black patients with stroke and carotid megabulbs with fibrous components, two of whom had superimposed thrombi.

Age-related changes of neuronal counts in the human pedunculopontine nucleus.

Cholinergic neurons in the basal forebrain and the upper brainstem undergo changes during aging and in dementia of the Alzheimer type, Parkinson's disease and progressive supranuclear palsy. Little is known about the effect of age on neurons in the tegmental pedunculopontine nucleus. Cholinergic neurons revealed by choline acetyltransferase immunohistochemistry were quantified in the brains of 20 subjects who died without neurological disorder between 28 and 101 years of age. A U-shaped relationship between cell counts and age was found, namely, a decrease in counts between 28 and 70, a minimum between 80 and 91 years of age, and, in four subjects aged 98-101 years counts comparable to those of subjects having died between 28 and 65 years. The findings suggest that the loss of cholinergic pedunculopontine nucleus neurons is not linear. In centenarians age-related neuronal decrease in pedunculopontine nucleus neurons may be slower or the stock of pedunculopontine nucleus neurons greater than in subjects dying earlier.

[Peripheral neuropathy caused by thallium poisoning]. / Neuropathie périphérique par intoxication au thallium.

A 20-year-old man developed over three weeks a sensory and painful neuropathy associated with diffuse alopecia. There was motor weakness, and superficial and deep hypoesthesia of the inferior limbs. Deep tendon reflexes were normal. Electrophysiological study mainly showed axonal motor neuropathy. This patient was admitted six weeks after the first symptoms. The clinical picture suggested thallium poisoning, which was confirmed by thallium concentrations in plasma, urine, hair and nails. After search, thallium was identified in a rat poison.

[Angioplasty of atheromatous hemodynamic stenoses of intracranial vertebral arteries]. / Angioplastie de sténoses athéromateuses hémodynamiques des artères vertébrales intracrâniennes.

We describe three patients presenting transient ischemic attacks or minor stroke, relapsing despite anticoagulation and antiplatelet therapy, in relation to tight stenosis of the intracranial vertebral arteries, without functional communicating arteries. Percutaneous transluminal angioplasty was successfully performed. We have a 6, 24 and 36 months follow-up. After a review of the literature, we discuss indication and risks of this procedure.

Understanding angiogenesis: a clue for understanding vascular malformations.

Vasculogenesis is defined by the differentiation of mesodermal precursors into endothelial cells, and angiogenesis by the formation of new vessels from preexisting vessels. Growth factors initiate cellular differentiation but also induce endothelial migration and proliferation; extracellular proteolysis is essential for disassembly and reassembly of endothelial cells to their environmental matrix and allow their migration to elongate the arterial tree. The coagulation and fibrinolysis system, metalloproteinases and adhesion molecules are critical during this step. The balance between pro- and antiangiogenic factors regulates angiogenesis. Ongoing studies dissecting angiogenesis mechanisms offer a new perspective to our understanding of vascular malformations.

[Neurosurgical embryology. Part 4: What are stem-cells?]. / Les cellules-souches, un outil thérapeutique pour le futur?

Stem-cells have been identified in the adult human brain in two zones which are the subventricular zone and the gyrus dentatus of the hippocampus. Improvement of techniques aimed to identify, to localize and to follow the lineage of these cells have been crucial to the understanding of the following processes: a) identification of cellular proliferation, b) specific immunostaining of differentiated glial and neuronal cells, c) transplantations to decipher between intrinsic stem-cell properties and influence of the environment on the fate of the cell. Furthermore, it seems that stem-cells from other sources than the brain can differentiate into neurons both in vitro and in vivo. The aim of this review is to sum up what is known about cerebral stem-cells and the challenging tools they mean for the future.

[Development and maturation of the pyramidal tract]. / Développement et maturation du faisceau pyramidal.

The pyramidal tract contains axons that originate from neurons located in layer 5 of the neocortex of the frontal areas 4 and 6 and of the parietal lobe. These neurons are generated during the first half of gestation in humans. The growth of these axons is highly regulated and the mechanisms that control this growth begin to be unravelled. For example, netrins could serve as chemattractants, the adhesion molecule L1 plays a crucial role in the control of axonal decussation at the level of the medulla, the ephrin B3-Eph A4 couple prevents the axons from crossing the midline. During development, the total number of pyramidal axons increases progressively and then decreases by regression of exuberant collaterals. The pyramidal tract is the sole unmyelinated tract in the human spinal cord at birth. This accounts for the protracted central conduction time in newborns. This immaturity of the pyramidal system could explain the existence of specific motor reflexes in newborns (the so-called primary reflexes) that disappear as the pyramidal system matures.

[Neurosurgical embryology. Part 8: Post-natal angiogenesis and remodeling]. / Angiogenèse post-natale et remodelage. Un stimulus majeur: les contraintes hémodynamiques.

Post-natal angiogenesis (microvascular proliferation) and remodeling (modifications of diameter and wall thickness) occur in various physiological circumstances including adaptation to exercise or wound healing. The formation of a new vessel is submitted to the combinative action of growth factors. New endothelial cells migrate, proliferate, differentiate and attract pericytes and future smooth muscle cells to create the new vessel. Powerful stimuli leading to remodeling and to the creation of new vessels are mainly represented by hemodynamic forces generated by pressure and blood flow, and by hypoxia. Our purpose is to overview the molecular mechanisms and the stimuli giving rise to these processes.

[Vasculogenesis and angiogenesis: molecular and cellular controls. part I: growth factors]. / Vasculogenèse et angiogenèse: contrôles moléculaires et cellulaires. lère Partie: les facteurs de croissance.

Angiogenesis characterizes embryonic development, but occurs also in adulthood, under physiological circumstances like adaptation to muscular exercise or in pathology like cancers. Knowledge of these mechanisms has step forward partly due to knock-out mice that have allowed to devoid an exact role to the different growth factors that are involved. Interestingly, the same growth factors and their receptors are equally involved during development and adulthood. We have detailed here their respective role and how interactions between them leads to a newly formed vessel.