[Optic neuritis: aetiopathogenesis, diagnosis, prognosis and management]. / Neuritis óptica: etiopatogenia, diagnóstico, pronóstico y manejo.

The main causes of optic neuritis (ON) are multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody disease, also known as MOGAD. When all screening is negative, we can speak of idiopathic ON, although this diagnosis should be provisional. ON can be diagnosed clinically and paraclinical tests are not routinely required to confirm it. However, tests such as magnetic resonance imaging (MRI), visual evoked potentials (VEP) and optical coherence tomography (OCT) can lend support to the diagnosis if the clinical presentation is atypical. The use of new MRI sequences, OCT, multifocal VEPs and the determination of neurofilaments has allowed ON to be used as a model for remyelination and neuroprotection, leading to phase II clinical trials. Some of these drugs, such as opicinumab, clemastine, phenytoin or simvastatin, have shown positive results; however, their clinical effect remains to be defined. It is accepted that corticosteroids do not improve the long-term prognosis of ON, although some retrospective studies suggest that there is a therapeutic window from the onset of symptoms. Plasmapheresis has also been shown to be effective in patients with ON. In this review we will address basic aspects of the management of ON, in the fundamental context of MS, NMOSD and MOGAD, with emphasis on etiopathogenic, diagnostic, prognostic and therapeutic developments.

TITLE: Neuritis óptica: etiopatogenia, diagnóstico, pronóstico y manejo.La neuritis óptica (NO) tiene como principales causas la esclerosis múltiple (EM), las enfermedades dentro del espectro de la neuromielitis óptica (NMOSD) y la enfermedad asociada a anticuerpos contra la proteína de la mielina del oligodendrocito, también conocida como MOGAD. Cuando todo el cribado es negativo, podemos hablar de NO idiopática, aunque este diagnóstico deberá ser provisional. La NO se puede diagnosticar clínicamente y no se requieren de forma rutinaria pruebas paraclínicas para confirmarla. Sin embargo, pruebas como la resonancia magnética (RM), los potenciales evocados visuales (PEV) y la tomografía de coherencia óptica (OCT) pueden dar soporte al diagnóstico si la presentación clínica es atípica. El uso de nuevas secuencias de RM, la OCT, los PEV multifocales y la determinación de neurofilamentos han posibilitado el uso de la NO como modelo de remielinización y neuroprotección, propiciando la realización de ensayos clínicos de fase II. Algunos de estos fármacos, como el opicinumab, la clemastina, la fenitoína o la simvastatina, han obtenido resultados positivos; no obstante, su efecto clínico está por definir. Se acepta que los corticoides no mejoran el pronóstico a largo plazo de la NO, aunque algunos estudios retrospectivos sugieren que existe una ventana terapéutica desde el inicio de los síntomas. La plasmaféresis también ha demostrado eficacia en pacientes con NO. En esta revisión abordaremos aspectos básicos del manejo de la NO, en el contexto fundamental de la EM, la NMOSD y la MOGAD, haciendo hincapié en las novedades etiopatogénicas, diagnósticas, pronósticas y terapéuticas.

Do multimodal evoked potentials add information to MRI in clinically isolated syndromes?

The role of multimodal evoked potentials (MMEPs) in establishing multiple sclerosis (MS) diagnosis and prognosis has diminished nowadays. The objective of this article is to evaluate whether MMEPs add information to MRI in identifying patients with higher risk of relapse or development of disability after a clinically isolated syndrome (CIS). Patients who underwent visual, somato-sensory and brainstem auditory evoked potentials (EPs) were identified from a cohort of consecutive CIS. Patients also underwent brain MRI within 3 months of first attack. We analysed time to second attack and to Expanded Disability Status Scale (EDSS) score of 3.0 according to number of Barkhof criteria and number of abnormal MMEPs. A complete study was performed in 245 patients who were followed for a mean of 76.4 months (interquartile range: 61 to 96). Seventy-one patients (29%) had the three EPs normal, 115 patients (47%) had one abnormal EP; 40 patients (16%) had two; and 19 patients (8%) had three abnormal EPs. Baseline MRI determined the risk for converting to clinically definite MS and correlated with disability according to previous studies. EPs individually did not modify the risk of conversion or disability. However, the presence of three abnormal EPs increased the risk of reaching moderate disability (hazard ratio 7.0; 1.4-34.9) independently of baseline MRI. In conclusion, in the presence of three abnormal EPs could help identify CIS patients with a higher risk of developing disability, independently of MRI findings. However, the utility of MMEPs is limited by the low percentage of CIS patients having the three abnormal at baseline.

[Detection of episodes of ischemic tissue hypoxia by means of the combined intraoperative neurophysiologic monitoring with the tissue oxygenation monitoring in aneurysm surgery]. / Detección de episodios de hipoxia tisular isquémica mediante la monitorizaciónneurofisiológica intraoperatoria combinada con la monitorización de la oxigenacióntisular en la cirugía aneurismática.

INTRODUCTION: Intraoperative neuromonitoring in aneurysm surgery can be very useful to determine inadequate positions of the vascular clip that cause partial or complete compromise of the cerebral sanguineous flow in the vascular territories irrigated by the arteries related to aneurysm. The direct visualization of these arteries after the application of the surgical clip can be insufficient in detecting this potentially detrimental situation. Knowing this circumstance on the onset would allow the neurosurgeon to correct it and to avoid, therefore, cerebral ischemic tissue hypoxia. We show the utility of the intraoperative monitoring of the oxygen tissue pressure (PtiO2) and the somatosensorial evoked potential (SSEP) for the detection of these situations with the example of a clinical case. CLINICAL CASE: We present the case of a 62 year-old woman, that presented with subarachnoid hemorrhage of aneurysmal origin. The cerebral arteriography demonstrated the existence of an aneurysm of the posterior communicating artery that was treated initially by endovascular procedure with partial exclusion of the aneurysm. For this reason it was decided to complete the treatment with a programmed surgery. The patient was put on an intraoperative monitoring system with a PtiO2 sensor located in the risk area and with SSEP. After positioning the surgical clip the partial oxygen pressure decreased rapidly, as well as the amplitude of the cortical potential of the left posterior tibial nerve. The knowledge of this situation allowed the detection of a trapped posterior communicating artery. After correcting this situation by replacing the surgical clip, both variables recovered to their basal values. CONCLUSIONS: The intraoperative PtiO2 monitoring, combined with neurophysiologic monitoring during aneurysm surgery offers a fast and trustworthy form of early detection of ischemic phenomena caused by bad positioning of the surgical clip.

Brainstem auditory and somatosensory evoked potentials: a methodological study to evaluate the reproducibility of two devices.

We aimed to determine whether statistical significant differences exist between the sets of results obtained from two devices used in our department for measuring brainstem auditory evoked potentials (BAEPs) and somatosensory evoked potentials (SEPs). We obtained BAEP and median and posterior tibial nerve SEP values bilaterally in ten healthy subjects. The tests were performed on the same subject using two devices consecutively. The equipment consisted of a Nicolet Viking-IV (Nicolet, Madison, WI, USA) and a Viking Select (Viasys Healthcare, Madison, WI, USA), and the same recording electrodes and stimulator (auditory and electrical) were used without modifying any postural position of the subject. The stimuli and recording parameters were the same for both devices. We obtained 20 sets of data for each type of test. The Bland­Altman plots as well as the one-sample t-test or Wilcoxon signed rank test were used to compare data between the two groups of data sets. We found no significant differences between the sets of values obtained with the two devices. Our analysis indicates that the two devices are equal in recording all different variables of BAEP and SEP, which allows us to combine the BAEP and SEP data obtained from the two devices for follow-up studies involving quantitative statistical methods. This study received institutional approval (protocol number PRAG-154/2013).