PubMed Health⌕ Search

Biomedical subjects

Leonardo Bonilha

Publications and source records attributed to Leonardo Bonilha.

30 records · Page 2Linked to original sources
PubMed2004

Epilepsy due to a destructive brain lesion caused by a scorpion sting.

BACKGROUND: Symptomatic acute epileptic seizures may occur in up to 5% of individuals, especially children, with scorpion stings. The occurrence of a long-lasting brain lesion or the development of epilepsy after a scorpion sting has never been observed. OBJECTIVE: To describe the development of epilepsy secondary to an extensive hemispheric destructive brain lesion after a scorpion sting. PATIENT: A 15-year-old with a moderate global cognitive impairment and a mild left hemiparesis, with seizures occurring approximately once monthly. RESULTS: The mother reported that the patient at the age of 4 years was stung by a brown scorpion, Tityus serrulatus. The patient soon developed local pain and paresthesias followed by diaphoresis and somnolence. Approximately 24 hours after the sting, she began to convulse. She was then taken to a hospital where she achieved suboptimal seizure control, with daily tonic-clonic seizures and left hemiplegia during the following week. During our clinical investigation, her routine electroencephalogram showed the presence of interictal spikes and diffuse slowing in the right brain hemisphere. Magnetic resonance imaging showed a widespread destructive lesion of her right cerebral hemisphere affecting both the cortical and subcortical structures. CONCLUSION: This is a rare illustration of the biological effects of the toxin of T serrulatus concerning its excitotoxicity and the potential to induce a brain lesion of an epileptogenic nature.

Animals↗
PubMed2004

Voxel-based morphometry reveals gray matter network atrophy in refractory medial temporal lobe epilepsy.

BACKGROUND: Conventional volumetric studies have shown that brain structures functionally and anatomically related to the hippocampus are smaller in patients with drug-refractory medial temporal lobe epilepsy (MTLE). OBJECTIVES: To determine the extent of gray matter atrophy in the brains of patients with MTLE and to examine the pattern of atrophy. DESIGN: We performed a voxel-based morphometric study of 43 consecutive patients with unilateral drug-refractory MTLE (21 patients with right-sided MTLE and 22 patients with left-sided MTLE) whose magnetic resonance images showed signs of unilateral hippocampal atrophy. The data from the patients with MTLE were compared with the data from 49 healthy control subjects to identify differences between groups in gray matter concentration (GMC). SETTING: Academic hospital's epilepsy clinic. RESULTS: We observed that patients with left- and right-sided MTLE exhibited GMC reduction in the hippocampus ipsilateral to the seizure origin. In addition, we found GMC reduction in the ipsilateral parahippocampal and isocortical temporal regions. Patients with MTLE also showed GMC reduction in subcortical nuclei such as the thalamus and caudate, in the cerebellum, in the midbrain, and in parieto-occipital regions. CONCLUSIONS: Patients with MTLE exhibit a reduction in GMC in regions outside the temporal lobe, specifically in areas that are connected to the hippocampus and parahippocampal region, suggesting an anatomical route for atrophy.

Adult↗
PubMed2004

Protocol for volumetric segmentation of medial temporal structures using high-resolution 3-D magnetic resonance imaging.

Quantitative analysis of brain structures in normal subjects and in different neurological conditions can be carried out in vivo through magnetic resonance imaging (MRI) volumetric studies. The use of high-resolution MRI combined with image post-processing that allows simultaneous multiplanar view may facilitate volumetric segmentation of temporal lobe structures. We define a protocol for volumetric studies of medial temporal lobe structures using high-resolution MR images and we studied 30 healthy subjects (19 women; mean age, 33 years; age range, 21-55 years). Images underwent field non-homogeneity correction and linear stereotaxic transformation into a standard space. Structures of interest comprised temporopolar, entorhinal, perirhinal, parahippocampal cortices, hippocampus, and the amygdala. Segmentation was carried out with multiplanar assessment. There was no statistically significant left/right-sided asymmetry concerning any structure analyzed. Neither gender nor age influenced the volumes obtained. The coefficient of repeatability showed no significant difference of intra- and interobserver measurements. Imaging post-processing and simultaneous multiplanar view of high-resolution MRI facilitates volumetric assessment of the medial portion of the temporal lobe with strict adherence to anatomic landmarks. This protocol shows no significant inter- and intraobserver variations and thus is reliable for longitudinal studies.

Adult↗
PubMed2004

Heavy coffee drinking and epilepsy.

Dietary habits have been rarely associated with seizure frequency in patients with epilepsy. We report a case of a man with a partial symptomatic epilepsy whose daily habit of heavy coffee drinking was associated with an increased seizure frequency. This patient witnessed a dramatic decrease in the frequency of his seizures after stopping coffee ingestion. Caffeine is a global stimulant and the reduction of its intake may help in the treatment of epilepsy.

Brain↗
PubMed2003

Temporal lobe hypogenesis associated with arachnoid cyst in patients with epilepsy.

OBJECTIVE: To determine the frequency of temporal lobe hypogenesis (TLH) associated with arachnoid cysts (AC) in patients with epilepsy. METHOD: We retrospectively revised 655 consecutive MRI scans from patients followed in our epilepsy clinic. We identified patients with temporal AC and then performed careful visual analysis in a workstation. Patients with evident expansive or destructive lesions were excluded. RESULTS: Only 4 (0.6%) patients had AC in the left temporal lobe, all associated with TLH. In addition, there were also ipsilateral dysgenetic characteristics in the ipsilateral hippocampus including abnormal shape and axis, and hyperintense T2 signal. In one patient this hippocampal abnormality was bilateral. CONCLUSION: AC with TLH was rarely found in our patients with epilepsy and it was always associated with hippocampal dysgenesis. Although volumetric reduction of the temporal lobe can be observed in patients with epilepsy and hippocampal abnormalities, the presence of adjacent AC points to a malformative etiology.

Adolescent↗
PubMed2003

Effects of method and MRI slice thickness on entorhinal cortex volumetry.

We assessed the effect of the method of analysis and the MRI slice thickness on entorhinal cortex volumetry. A T1 gradient echo 3D volumetric acquisition was reformatted into different slice thickness and analyzed by edge-tracing. We performed two different forms of analysis of images with 3 mm slice thickness: edge-tracing and pixel by pixel. There was difference among the volumes obtained from different slice thickness (p < 0.001), and also difference between the two different methods of analysis (p < 0.05). The use of thick slices is time saving, but volumes are linearly increased; different methods of segmentation also yields different values. The form of volumetric analysis of the entorhinal cortex should be evaluated in advance to prevent false estimates in longitudinal studies.

Adult↗
PubMed2003

Multiple systemic metastases of posterior fossa - primitive neuroectodermal tumor (PF-PNET) in adult: case report.

We present the case of a 30-year female patient with multiple systemic metastases of posterior fossa primitive neuroectodermal tumor (PF- PNET) and present a review concerning the usual presentation, sign and symptoms, radiological aspects, pathways of spread, genetic patterns and treatment of PF-PNET. The biological behavior of PF - PNET is analyzed taking into consideration the presence of systemic metastases.

Adult↗
PubMed2003

Chronic epidural hematoma of the vertex.

Epidural hematomas of the cranial vertex can be rarely found in patients victims of head trauma. The diagnosis of the vertex hematoma may be delayed by the odd location of the bleeding site and the absence of a clear localization symptomatology. The current method of choice for investigation of head trauma patients, the computed tomography (CT) scans, may also give misleading diagnostic clues. Epidural hematomas of the vertex can be also encountered in a chronic form, and re-bleeding is possibly the underlying mechanism for the long term permanence of the hematoma. We report a case of a patient with a chronic epidural hematoma of the cranial vertex with a long interval between the trauma and the symptoms onset. We review the current literature focusing on the diagnostic pitfalls and forms of treatment of the chronic epidural hematoma of the vertex.

Adult↗
PubMed2003

Texture analysis of hippocampal sclerosis.

UNLABELLED: Mesial temporal lobe epilepsy (MTLE) is frequently associated with refractory seizures and pathologic features of hippocampal sclerosis (HS). Quantitative magnetic resonance imaging (MRI) techniques can improve the detection and quantification of HS. The objective of this study was to evaluate whether MRI texture analysis can detect hippocampal abnormalities in patients with pathologically proven HS. METHODS: Nineteen consecutive patients who underwent surgery for refractory unilateral MTLE and had HS diagnosed on histopathology (12 right and seven left) had their preoperative MRIs evaluated. We performed texture analysis in 3-mm coronal T1-IR MRIs, focusing on the hippocampal head, by using the software MAZDA. Data were compared with those of a group of 78 normal hippocampi from 39 healthy adult volunteers through multivariate analysis of variance and selection of the most significant texture parameters. RESULTS: Overall, almost all parameters of texture could discriminate the group of hippocampi with HS and the group of contralateral hippocampi from the group of normal hippocampi, but the post hoc comparison showed no differences between HS and contralateral hippocampi. CONCLUSIONS: These results provide evidence of texture alteration in MRIs of hippocampi with HS and corroborate the hypothesis of bilaterality of hippocampal damage in patients with MTLE, but further studies are needed to investigate the lateralization power of texture analysis.

Adolescent↗
PubMed2002

Bilateral internuclear ophthalmoplegia and clivus fracture following head injury: case report.

Internuclear ophthalmoplegia is a remarkable finding, particularly in patients victims of head injury. The medial longitudinal fasciculus, which is believed to be lesioned in cases of internuclear ophthalmoplegia, has an unique brain stem position and the mechanism involved in brain stem contusions implies a maximal intensity of shearing forces on the skull base. We describe a very rare association of bilateral ophthalmoplegia and clivus fracture following head injury, without further neurological signs. The patient history, his physical examination and the image investigation provide additional evidence to some of the mechanisms of injury proposed to explain post-traumatic internuclear ophthalmoplegia.

Adult↗