What does epileptic nystagmus show us in cases presenting acute neurological symptoms?

PURPOSE: This study aims to determine the clinical significance of epileptic nystagmus in patients with acute neurological symptoms. METHOD: The clinical findings of patients with documented epileptic nystagmus, their original video and EEG data, and cranial imaging and laboratory tests were analyzed retrospectively. RESULTS: 20 patients were included in the study and 21 epileptic nystagmus attacks were determined from patients' clinical and video-EEG recordings. All recorded seizures with epileptic nystagmus were focal onset in nature. The ictal discharge pattern was rhythmic fast activity with a mean frequency of 15 Hz. The ictal discharges originated from the parieto-occipital (n = 8), temporo-occipital (n = 7), parieto-occipito-temporal (n = 3), temporal (n = 2), occipital (n = 1), and centroparietal (n = 1) areas. In the fast phase, the nystagmus was beating away from the side of ictal discharges. The origin of the ictal discharges on EEG images was compatible with the lesion localization at cranial MRI in all patients. Etiologies were epilepsy in seven patients, non-ketotic hyperglycemia in four, ketotic hyperglycemia in one, PRES in three, acute stroke in three, HSV encephalitis in one, and MELAS in one. CONCLUSIONS: Epileptic nystagmus represents a guide to the lateralization and localization of the lesion in cases presenting with acute neurological symptoms. In these patients, the lesion is frequently in the posterior regions of the hemispheres. Although various diseases affect these regions in terms of etiology, such cases should be evaluated in terms of the presence of hyperglycemia.

An Unusual Case Presenting with New Onset Epileptic Seizure and Unilateral Temporal Lobe Lesion Diagnosed as Influenza Type A Associated Encephalitis.

Influenza A viruses, known etiological agents of seasonal outbreaks, epidemics, and pandemics, are RNA viruses of the Orthomyxoviridae family. They can manifest with a wide range of neurological complications. Influenza related encephalitis is rarely reported and poorly characterized in adults. Its diagnosis is hampered by significant variation in clinical presentation and difficulties in virus detection in the cerebrospinal fluid. Diffuse brain edema, symmetric involvement of thalamus, brain stem, and cerebellum, or normal findings in the acute phase followed by the appearance of diffuse low attenuation and mild brain atrophy are reported cranial magnetic resonance imaging findings, but unilateral temporal lobe involvement has not been observed before. Here we describe an unusual adult case who presented with new-onset epileptic seizures and unilateral temporal lobe lesion mimicking herpes simplex encephalitis but a polymerase chain reaction of cerebrospinal fluid confirmed influenza type A associated encephalitis.

What is the role of diffusion tensor imaging (DTI) in detecting subclinical pyramidal tract dysfunction in Behçet's and neuro-Behçet's cases?

The aim of this study is to investigate the pyramidal tract integrity with DTI in Behçet's and neuro-Behçet's cases. We performed this technique in two subgroups of neuro-Behçet's patients (parenchymal and vascular), and Behçet's cases without neurological involvement and control group. Totally, 28 patients were investigated. The control group was composed of 14 healthy people. Cranial MR and DTI were performed in three patient groups and the control group. At DTI, circular regions of interest (ROI) were symmetrically drawn on axial slices on the left and right sides along the pyramidal tract pathway at two levels: middle one third of the cerebral peduncle and posterior limb of the internal capsule. Fractional anisotropy (FA) values for each ROI were obtained by averaging all voxels within the ROI. Calculated FA values on both sides (left and right) of the posterior limb of the internal capsule and cerebral peduncle are significantly lower in all three patient groups when compared to the control group. But there is no any difference of FA values in the selected brain regions of three patient groups. FA values on the posterior limb of the internal capsule and cerebral peduncle do not show a statistically significant difference in parenchymal neuro-Behçet's cases. Our study demonstrates that DTI can detect subclinical pyramidal tract dysfunction in neuro-Behçet's and Behçet's patients. Detection of subclinical nervous system involvement is crucial for morbidity in Behçet's disease. For this reason, studies based on DTI, which include a large number of patients and explore different brain regions, are needed to guide clinicians.