RESUMO
ANTECEDENTES: Las gestaciones múltiples sugieren un mayor riesgo de mortalidad perinatal. Dentro de estas estadísticas, la muerte de un solo gemelo ocurre en hasta el 6% de los embarazos múltiples. La incidencia general después de las 20 semanas de gestación (sdg) se estima entre el 2.6% y el 6.2% de todos estos embarazos. Se ha demostrado que es la coriónicidad, más que la cigosidad, la que influye en el resultado de esta complicación, debido a la angioarquitectura placentaria de las circulaciones en los embarazos monocoriónicos. Las tasas de pérdida de hasta el 30-50% se han asociado con embarazos monocoriónicos y monoamnióticos. Si ocurre antes de las 14 sdg, el embrión puede desaparecer; entre las 14 y las 20 sdg, el feto se reduce en tamaño y volumen. Y, si ocurre después de 20 sdg, el feto permanece dentro del útero hasta el final de la gestación. CASO CLÍNICO: femenina de 18 años de edad, quien acudió a revisión obstétrica con reporte ultrasonográfico de un embarazo gemelar monocorial biamniótico de 30.4 sdg, y muerte de uno de los gemelos. Tras demostrar estabilidad hemodinámica del feto sobreviviente, así como estabilidad materna, se decidió internamiento para monitoreo estrecho. Una semana después desarrolló trabajo de parto pretérmino y se decidió la interrupción de la gestación de manera urgente. Se obtuvo un recién nacido masculino con edad gestacional sugestiva de 32 sdg, con dificultad respiratoria y requirió hospitalización para monitoreo estrecho del recién nacido prematuro. Madre egresó a las 48 horas, nunca desarrolló datos de coagulación intravascular diseminada (CID) y el recién nacido se mantuvo en hospitalización aproximadamente 3 semanas y media hasta que se egresó por adecuada adaptación. Nunca se demostró afectación neurológica o de algún otro órgano o sistema. CONCLUSIONES: Los factores más importantes al considerar el riesgo para el gemelo sobreviviente son la edad gestacional a la que ocurre la muerte del otro feto, y la corionicidad. El manejo debe incluir ecografías seriadas y programadas para el crecimiento. Estudios de Doppler arterial/venoso periférico e intracardiaco y una resonancia magnética al menos 3 semanas después de la muerte fetal para buscar cambios en el cerebro del gemelo sobreviviente. A pesar de que existen casos reportados de manejo conservador, es necesario el seguimiento estricto de datos de CID maternos, así como de desprendimiento prematuro de placenta normoinserta. (provisto por Infomedic International)
BACKGROUND: Multiple gestations suggest an increased risk of perinatal mortality. Within these statistics, death of a single twin occurs in up to 6% of multiple pregnancies. The overall incidence after 20 weeks gestation (sdg) is estimated to be between 2.6% and 6.2% of all such pregnancies. Chorionicity, rather than zygosity, has been shown to influence the outcome of this complication, due to the placental angioarchitecture of the circulations in monochorionic pregnancies. Loss rates of up to 30-50% have been associated with monochorionic and monoamniotic pregnancies. If it occurs before 14 sdg, the embryo may disappear; between 14 and 20 sdg, the fetus is reduced in size and volume. And, if it occurs after 20 sdg, the fetus remains inside the uterus until the end of gestation. CLINICAL CASE: 18-year-old female, who attended an obstetric check-up with an ultrasonographic report of a biamniotic monochorionic twin pregnancy of 30.4 sdg, and death of one of the twins. After demonstrating hemodynamic stability of the surviving fetus, as well as maternal stability, it was decided to hospitalize her for close monitoring. One week later she developed preterm labor and it was decided to terminate the pregnancy urgently. A male newborn was obtained with a gestational age suggestive of 32 sdg, with respiratory distress and required hospitalization for close monitoring of the premature newborn. Mother was discharged at 48 hours, never developed disseminated intravascular coagulation (DIC) and the newborn remained in hospital for approximately 3 and a half weeks until he was discharged due to adequate adaptation. No neurologic or other organ or system involvement was ever demonstrated. CONCLUSIONS: The most important factors when considering the risk to the surviving twin are the gestational age at which the death of the other fetus occurs, and chorionicity. Management should include serial and scheduled ultrasounds for growth. Peripheral arterial/venous and intracardiac Doppler studies and MRI at least 3 weeks after fetal death to look for changes in the brain of the surviving twin. Although there are case reports of conservative management, close monitoring of maternal DIC data, as well as normoinsert placental abruption, is necessary. (provided by Infomedic International)
RESUMO
PURPOSE: Temporal lobe epilepsy is associated with tissue abnormalities of several gray and white matter structures that are reproduced in animal models. Few longitudinal studies have focused on the identification of structural differences during epileptogenesis. The diffusion tensor model is a useful tool for evaluating cell death, gliosis, and axonal plasticity in epileptic subjects. This study aimed to evaluate temporal tissue changes after experimental status epilepticus in an animal model of chronic temporal lobe epilepsy. METHODS: Systemic pilocarpine-induced status epilepticus in adult Sprague-Dawley rats. Animals were scanned using diffusion tensor imaging (DTI) at three time points: prior to status epilepticus, and 24 and 64 days post-induction (early and late chronic, respectively). Fractional anisotropy, apparent diffusion coefficient, axial diffusivity (Dâ), and radial diffusivity (Dâ´) were evaluated in white (fimbria, cingulum, corpus callosum, and internal capsule) and gray (dorsal hippocampus, dentate gyrus, and CA3) matter regions for the three time points. Histological assessment of neurodegeneration in Klüver-Barrera preparations from the same animals was performed. RESULTS: Significantly reduced volume of dorsal hippocampus and fimbria of the epileptic animals was observed already at 24 days post-status epilepticus. Progressive changes of DTI parameters in both the white and gray matter structures of the experimental group were also observed. Stained sections confirmed such alterations. CONCLUSION: Our study revealed time-dependent diffusion changes in gray and white matter structures after pilocarpine-induced status epilepticus. The characterization of these alterations over time may be potential imaging markers for epileptogenesis.
Assuntos
Substância Branca , Animais , Imagem de Tensor de Difusão , Substância Cinzenta , Pilocarpina/toxicidade , Ratos , Ratos Sprague-Dawley , Substância Branca/diagnóstico por imagemRESUMO
INTRODUCTION: Spontaneous ventriculomegaly has been observed in rats that were presumed normal. Because the external phenotype of these animals is unremarkable, they can be inadvertently included in behavioral experiments, despite the considerable enlargement of the ventricular system, reduced cortical thickness, and hippocampal atrophy upon imaging. Given the role of such structures in memory consolidation, we evaluated long-term memory retention while decision making in rats with spontaneous ventriculomegaly. METHODS: We studied adult male Sprague Dawley rats, identified as having spontaneous ventriculomegaly, while performing baseline magnetic resonance imaging scanning intended for a different research protocol. Control (n = 7) and experimental (n = 6) animals were submitted to a delayed-alternation task (no delay, 30, 60, and 180 s) and an object-in-context recognition task. During the first task, we evaluated the number of correct choices as well as the latency to reach any of the cavities located at the end of each branch arm during each trial. The second task assessed the rodents' ability to remember where they had previously encountered a specific object, calculating the context recognition index. RESULTS: When compared to control animals, rats with spontaneous ventriculomegaly required significantly more training sessions to reach the 80% criterion during the training phase. Moreover, they showed reduced delayed-alternation performance in the evaluated times, reaching significance only at 180 s. Increased latencies while trying to reach the cavity were also observed. Evaluation of the long-term memory formation during the object-in-context recognition task showed that subjects with ventriculomegaly spent less time investigating the familiar object, resulting in a significantly decreased recognition index value. CONCLUSION: Our results are the first to show how spontaneous ventriculomegaly-induced cerebral structural damage affects decision-making behaviors, particularly when comparing between immediate and delayed trials. Moreover, this lesion disrupts the animals' ability to recall or express contextual information.