Hippocampal signal abnormality on the first day of illness in acute encephalopathy with biphasic seizures and late reduced diffusion caused by HHV-6 infection

HHV-6-Associated Neurological Disease in Children: Epidemiologic, Clinical, Diagnostic, and Treatment Considerations

Human herpesviruses 6A and 6B, often referred to collectively as human herpesvirus 6, are a pair of beta-herpesviruses known to cause a variety of clinical syndromes in both immunocompetent and immunocompromised individuals. Most humans are infected with human herpesvirus 6B, and many with human herpesvirus 6A. Primary infection typically occurs in early childhood, although large-scale reviews on the topic are limited. Herein, the authors explore the clinical manifestations of human herpesvirus 6-associated disease in both immunocompetent and immunocompromised pediatric patients, the risk factors for development of human herpesvirus 6-associated neurological disease, the risk of autoimmunity associated with development of active or latent infection, the relevance of human herpesvirus 6-specific diagnostic tests, and the medications used to treat human herpesvirus 6. The goal of this review is to improve the current understanding of human herpesvirus 6 in pediatric populations and to examine the most effective diagnostic and therapeutic interventions in this disease state.

Acute encephalopathy with biphasic seizures and late reduced diffusion in a Spanish girl

We report a case of a 22-month-old Spanish girl who presented acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). Serum procalcitonin (PCT) reached a maximum of 50.5 ng/mL on the first day whereas C-reactive protein (CRP) peaked at 1.21 mg/dL on the second. At the time of discharge, right spastic hemiparesis persisted. MR spectroscopy on day 23 revealed a decrease in N-acetylaspartate and an increase in choline. To our knowledge, we report the first case of AESD in Europe. These findings support the role of PCT and PCT/CRP ratio in the early diagnosis of AESD and correlation of MR spectroscopy findings with neurological outcome.

Human Herpesvirus 7-Related Acute Encephalopathy with Biphasic Seizures and Late Reduced Diffusion

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a recently described entity so far exclusively in East Asian children. AESD diagnosis is based on clinicoradiologic criteria, often without pleocytic CSF and characterized by hyperglycemia and transaminasemia. Here, we present the first case of human herpesvirus 7-related AESD in an immunocompetent child >2 years old and of Caucasian origin.

Acute DWI Reductions In Patients After Single Epileptic Seizures - More Common Than Assumed

Background: Changes of cerebral diffusivity detected by magnetic resonance imaging (MRI) have been reported in epilepsy. Diffusion weighted imaging (DWI) detects changes in the distribution of water molecules by measuring the apparent diffusion coefficient (ADC) and is mainly used in the diagnosis of ischemic stroke. DWI changes in epilepsy were reported in status epilepticus (SE) or series of seizures. It remains unclear whether this phenomenon also occurs after single seizures. Accordingly, possible pathomechanisms have only been discussed on the presumed basis of ongoing epileptic brain activity.

Methods: In this retrospective study, we systematically analyzed DWI alterations related to epileptic seizures in 454 patients who received MRI scanning within the first 24 h after seizure onset.

Results: DWI restrictions not classified as ischemic stroke were observed in 18 patients (4%). We found DWI restrictions in 19% of patients with SE/seizure series and in 3% of patients after single focal and 2.5% after single generalized seizures. 17 patients with DWI alterations were diagnosed with a structural epilepsy. DWI signal decreased in the majority of patients within the first days and could not be detected in follow-up imaging >3 months. In all patients except one, DWI alterations were detected in the same hemisphere as the lesion. In the case of seizure series or SE, DWI restrictions mostly presented with a typical “garland-like” pattern alongside the cortical band or on the border of a defined lesion, while in isolated seizures, the restrictions were often rather subtle and small.

Discussion: We show that DWI restrictions can be observed in patients after single epileptic seizures. As the vast majority of these patients was diagnosed with an epilepsy due to structural cerebral pathology, DWI restriction may reflect a higher vulnerability in these regions. This might also explain the fact that diffusivity changes were observed after single focal seizures as well as after multiple seizures or SE. The occurence itself on one side as well as the spatial pattern of this phenomenon on the other may thus not only be related to the duration of ictal activity, but to structural pathology.