Espectroscopia por ressonância magnética de prótons em epilepsia mioclônica juvenil sugere o comprometimento de uma rede neuronal específica / Proton magnetic resonance spectroscopy study of juvenile myoclonic epilepsy patients suggests involvement of a specific neuronal network

OBJECTIVES: The neuroanatomical basis and the neurochemical abnormalities that underlay juvenile myoclonic epilepsy (JME) are not fully defined. While the thalamus plays a central role in synchronization of widespread regions of the cerebral cortex during a seizure, emerging evidence suggests that all cortical neurons may not be homogeneously involved. The purpose of this study was to investigate the cerebral metabolic differences between patients with JME and normal controls. METHODS: All patients had a JME diagnosis based on seizure history and semiology, EEG recording, normal magnetic resonance neuroimaging (MRI) and video-EEG. Forty JME patients (JME-P) were submitted to 1.5 T MRI proton spectroscopy (1H-MRS), multi-voxel with PRESS sequence (TR/TE = 1500/30 ms) over the following locations: prefrontal cortex (PC), frontal cortex (FC), thalamus, basal nuclei, posterior cingulate gyrus (PCG), insular, parietal and occipital cortices. We determined ratios for integral values of N-acetyl aspartate (NAA) and glutamine-glutamate (GLX) over creatine-phosphocreatine (Cr). The control group (CTL) consisted of 20 age and sex-matched healthy volunteers. RESULTS: Group analysis demonstrated a tendency for lower NAA/Cr ratio of JME-P compared to CTL predominantly on FC, PC, thalamus and occipital cortex. When compared to CTL, JME-P had a statistically significant difference in GLX/Cr on FC, PC, insula, basal nuclei, PCG and on thalamus. When evaluating the relationship among the various components of this epileptic network among JME-P, the strongest correlation occurred between thalamus and PC. Also, we found a significant negative correlation between NAA/Cr and duration of epilepsy. CONCLUSION: Reductions in NAA may represent loss or injury of neurons and/or axons, as well as metabolic dysfunction while glutamate is considered to be an excitatory neurotransmitter in the brain which is involved in the pathogenesis of epileptogenic seizures.

Avaliaçäo da flebografia orbitária em oito casos de síndrome de Tolosa-Hunt / Orbital phlebography evaluation in 8 cases of Tolosa-Hunt syndrome

A Síndrome de Tolosa-Hunt (STH) ou oftalmoplegia dolorosa é associada a granulomatose inespecifica de etiologia desconhecida que acomete a fissura orbitária superior. Compromete estruturas nervosas e vasculares causando quadro clínico variável que sempre se associa a dor e apresenta resposta favorável à corticoterapia. Processos inflamatório, tumores e anmeurismas dessa regiäo podem causar sintomas semelhantes. A tomografia computadorizada, a angiografia cerebral e a flebografia orbitária säo métodos de imagem indicados para orientar o diagnóstico. Revisamos os resultados destes exames radiológicos de oito pacientes atendidos no Hospital Säo Paulo no período 1989 a 1991, com diagnóstico de STH segundo os critérios de Hunt e Hannerz. A análise das alteraçöes da flebografia orbitária, de acordo com a sistematizaçäo feita por Hannerz e col. Mostrou ser este exame inespecífico, porém capaz de orientar melhor mo diagnóstico

Tomografia computadorizada na intoxicaçäo por metanol: relato de caso / Computed tomography in methanol intoxication

Tivemos a oportunidade de acompanhar com exames de TC caso de intoxicaçäo por metanol. O paciente foi submetido ao exame no momento da internaçäo e após seis dias, pela persistência de quadro neurológico grave. Observou-se nesta última a presença de lesöes putaminais simétricas e da substância branca subcortical, apesar do tratamento adequado. A comprovaçäo tomográfica de lesöes cerebrais evidenciou efeito tóxico do metanol e pode orientar o prognóstico neurológico