White matter damage in neonatal enterovirus meningoencephalitis

The authors report six neonates with enteroviral meningoencephalitis. Five infants presented with prolonged seizures, and one presented with systemic enteroviral disease. Cranial ultrasonography showed increased echogenicity in the periventricular white matter, and MRI confirmed mild to severe white matter damage in all infants, which looked similar to periventricular leukomalacia. Two infants developed cerebral palsy: one was neurologically suspect at age 18 months, and three were developmentally normal.

Neurological manifestations of dengue virus infection

AIM

Paucity of studies on neurological manifestations in dengue virus infection prompted this study. We aim to correlate clinical, radiological and neurophysiological changes in dengue patients with neurological manifestations.

METHOD

Consecutive IgM seropositive dengue patients admitted in neurology ward during 2003-2005 have been prospectively evaluated. They were subjected to detailed clinical evaluation, blood counts, coagulation profile, serum chemistry including creatine kinase (CK), cerebrospinal fluid (CSF), cranial CT and/or MRI, electroencephalogram (EEG), nerve conduction and needle electromyography (EMG).

RESULTS

There were 17 patients, aged 5 to 56 years; 11 presented with encephalopathy and 6 with acute motor weakness. In the patients with encephalopathy, seizures were present in 3, myoclonus in 1, CSF pleocytosis and EEG slowing in 8 each and globus pallidus and thoracic spinal cord involvement on MRI in 1 patient each. In the pure motor weakness group, CK was elevated in 5 and EMG and muscle biopsy were consistent with myositis in 1 patient each. The patients with pure motor weakness improved completely but in the encephalopathy group 3 died, 2 had partial, 1 poor and 5 complete recovery by 1 month.

CONCLUSION

Dengue patients presenting with encephalopathy had more severe illness and worse outcome compared to acute pure motor weakness.

Kappa opioid control of seizures produced by a virus in an animal model

Epilepsy remains a major medical problem of unknown aetiology. Potentially, viruses can be environmental triggers for development of seizures in genetically vulnerable individuals. An estimated half of encephalitis patients experience seizures and approximately 4% develop status epilepticus. Epilepsy vulnerability has been associated with a dynorphin promoter region polymorphism or low dynorphin expression genotype, in man. In animals, the dynorphin system in the hippocampus is known to regulate excitability. The present study was designed to test the hypothesis that reduced dynorphin expression in the dentate gyrus of hippocampus due to periadolescent virus exposure leads to epileptic responses. Encephalitis produced by the neurotropic Borna disease virus in the rat caused epileptic responses and dynorphin to disappear via dentate granule cell loss, failed neurogenesis and poor survival of new neurons. Kappa opioid (dynorphin) agonists prevented the behavioural and electroencephalographic seizures produced by convulsant compounds, and these effects were associated with an absence of dynorphin from the dentate gyrus granule cell layer and upregulation of enkephalin in CA1 interneurons, thus reproducing a neurochemical marker of epilepsy, namely low dynorphin tone. A key role for kappa opioids in anticonvulsant protection provides a framework for exploration of viral and other insults that increase seizure vulnerability and may provide insights into potential interventions for treatment of epilepsy.

HHV-6 and seizures

Human herpes virus-6 (HHV-6) is a ubiquitous virus, but one that can induce various neurological diseases. Recently, several seizures have been reported as new HHV-6-associated diseases based on virological analysis. Neonates who are perinatally infected with HHV-6 can develop afebrile seizures, which are considered to be exanthem subitum (ES) in the neonatal period. Infants with ES also tend to develop atypical febrile seizures. After primary infection, HHV-6 commonly establishes latency in the central nervous system (CNS) and sometimes reactivates in the hippocampus, causing limbic encephalitis and temporal lobe epilepsy. These HHV-6-associated CNS diseases due to virus reactivation can occur in both immunocompromised and immunocompetent hosts. This article summarizes HHV-6-associated seizures during childhood.

A role for endocannabinoids in viral-induced dyskinetic and convulsive phenomena

Dyskinesias and seizures are both medically refractory disorders for which cannabinoid-based treatments have shown early promise as primary or adjunctive therapy. Using the Borna disease (BD) virus rat, an animal model of viral encephalopathy with spontaneous hyperkinetic movements and seizure susceptibility, we identified a key role for endocannabinoids in the maintenance of a balanced tone of activity in extrapyramidal and limbic circuits. BD rats showed significant elevations of the endocannabinoid anandamide in subthalamic nucleus, a relay nucleus compromised in hyperkinetic disorders. While direct and indirect cannabinoid agonists had limited motor effects in BD rats, abrupt reductions of endocannabinoid tone by the CB1 antagonist SR141716A (0.3 mg/kg, i.p.) caused seizures characterized by myoclonic jerks time-locked to periodic spike/sharp wave discharges on hippocampal electroencephalography. The general opiate antagonist naloxone (NLX) (1 mg/kg, s.c.), another pharmacologic treatment with potential efficacy in dyskinesias or L-DOPA motor complications, produced similar seizures. No changes in anandamide levels in hippocampus and amygdala were found in convulsing NLX-treated BD rats. In contrast, NLX significantly increased anandamide levels in the same areas of normal uninfected animals, possibly protecting against seizures. Pretreatment with the anandamide transport blocker AM404 (20 mg/kg, i.p.) prevented NLX-induced seizures. These findings are consistent with an anticonvulsant role for endocannabinoids, counteracting aberrant firing produced by convulsive agents, and with a functional or reciprocal relation between opioid and cannabinoid tone with respect to limbic convulsive phenomena.

Herpes simplex encephalitis

A 28-year-old woman presented with a one day history of high fever and partial seizures with secondary generalization. This was preceded by a three week history of headache, ataxia, and fatigue. An initial computed tomogram head scan showed a low density mass lesion in the right frontal operculum without enhancement. On the next day, a repeat scan showed a new frontopolar, expansile, low density cortical lesion (Figure 1A) suggestive of encephalitis. Cerebrospinal fluid showed a pleocytosis of 311 mononuclear white blood cell count per μL and an elevated protein of 1.57 g/L. She received intravenous acyclovir and antibiotics. She remained febrile and became mute. A magnetic resonance (MR) scan under general anesthesia on her fourth hospital day showed frontal and perisylvian lesions with restricted diffusion (Figure 1B - D and Figure 2). A right frontal brain biopsy showed meningoencephalitis and immunohistochemical staining was positive for herpes simplex virus (HSV) antigen (Figure 3). Subsequently, HSV-1 DNA was demonstrated in both cerebrospinal fluid and brain tissue with polymerase chain amplification. She improved after a course of intravenous therapy with acyclovir with residual frontal lobe signs, including marked executive dysfunction, and her speech became normal.

Hepatitis A virus infection presenting with seizures

Hepatitis A infection rarely causes extrahepatic manifestations. Here we present a 5-year-old patient with an initial complaint of nuchal rigidity and convulsions during the course of hepatitis A infection. Because hepatitis A virus RNA was demonstrated in the cerebrospinal fluid, it was thought that convulsions might be related to this viral infection.

Human herpesviruses-6 and -7 each cause significant neurological morbidity in Britain and Ireland

BACKGROUND

Primary human herpesvirus-6 and -7 (HHV-6/-7) infections cause febrile illness sometimes complicated by convulsions and rarely encephalopathy.

AIMS

To explore the extent of such HHV-6 and -7 induced disease in young children.

METHODS

In a three year prospective study in Britain and Ireland, 205 children (2-35 months old) hospitalised with suspected encephalitis and/or severe illness with fever and convulsions were reported via the British Paediatric Surveillance Unit network. Blood samples were tested for primary HHV-6 and -7 infections.

RESULTS

26/156 (17%) of children aged 2-23 months had primary infection (11 HHV-6; 13 HHV-7; two with both viruses) coinciding with the acute illness; this was much higher than the about three cases expected by chance. All 26 were pyrexial; 25 had convulsions (18 status epilepticus), 11 requiring ventilation. Median hospital stay was 7.5 days. For HHV-6 primary infection the median age was 53 weeks (range 42-94) and the distribution differed from that of uninfected children; for HHV-7, the median was 60 weeks (range 17-102) and the distribution did not differ for the uninfected. Fewer (5/15) children with primary HHV-7 infection had previously been infected with HHV-6 than expected.

CONCLUSIONS

Primary HHV-6 and HHV-7 infections accounted for a significant proportion of cases in those <2 years old of severe illness with fever and convulsions requiring hospital admission; each virus contributed equally. Predisposing factors are age for HHV-6 and no previous infection with HHV-6 for HHV-7. Children with such neurological disease should be investigated for primary HHV-6/-7 infections, especially in rare cases coinciding by chance with immunisation to exclude misdiagnosis as vaccine reactions.

Neurologic complications associated with respiratory syncytial virus

Encephalopathy has been demonstrated to be associated with respiratory syncytial virus bronchiolitis. In this study, the data on all patients less than 14 years of age hospitalized with respiratory syncytial virus bronchiolitis over the past 4 years was reviewed. Patients who had concomitant diagnoses consistent with neurologic disease underwent detailed chart review. There were 964 patients (age 0.1 to 13.6 years) with a diagnosis of respiratory syncytial virus bronchiolitis. Thirty-six of these patients had concurrent neurologic diagnoses. Twenty-four patients were excluded because of preexistent neurologic disorders, probable simple febrile seizures, or a history of epilepsy. Twelve respiratory syncytial virus-positive patients had definite neurologic complications without another recognized cause. Seven of these patients had seizures (predominantly generalized tonic-clonic and one with status epilepticus), three had generalized encephalopathy (marked hypotonia and decreased responsiveness) of whom two also developed esotropia. Two patients developed isolated esotropia. There was an incidence of neurologic complications of 1.2% (0.7% seizures) in a total of 964 patients with respiratory syncytial virus bronchiolitis. This percentage does not include presumed simple febrile seizures or exacerbations of preexisting seizure disorder (further 1.3%). Neurologic complications occur with respiratory syncytial virus bronchiolitis, and physicians and other caregivers should be aware of this entity as well as the favorable prognosis.

Fatal avian influenza A (H5N1) in a child presenting with diarrhea followed by coma

In southern Vietnam, a four-year-old boy presented with severe diarrhea, followed by seizures, coma, and death. The cerebrospinal fluid contained 1 white cell per cubic millimeter, normal glucose levels, and increased levels of protein (0.81 g per liter). The diagnosis of avian influenza A (H5N1) was established by isolation of the virus from cerebrospinal fluid, fecal, throat, and serum specimens. The patient's nine-year-old sister had died from a similar syndrome two weeks earlier. In both siblings, the clinical diagnosis was acute encephalitis. Neither patient had respiratory symptoms at presentation. These cases suggest that the spectrum of influenza H5N1 is wider than previously thought.

Dengue hemorrhagic fever complicated with acute pancreatitis and seizure

Dengue fever is an acute febrile viral disease, which frequently presents with high fever, headache, bone pain and skin rash. Acute pancreatitis and seizure are rare manifestations of dengue virus infection. A 66-year-old woman with diabetes mellitus presented with epigastralgia, nausea, vomiting, diarrhea and fever. Acute pancreatitis, abnormal liver function and thrombocytopenia were diagnosed at a local hospital. After persistent fever, thrombocytopenia and seizure developed she was transferred to our medical center. Dengue virus infection was confirmed by serology study and dengue hemorrhagic fever grade II was diagnosed. No further neurological symptoms occurred and pancreatitis improved gradually after supportive care. She recovered and had no sequelae at 1 year follow-up. Acute pancreatitis and seizure may be manifestations of dengue virus infection, especially in patients with delayed diagnosis, prolonged fever and thrombocytopenia.

Investigations into shaking mink syndrome: an encephalomyelitis of unknown cause in farmed mink (Mustela vison) kits in Scandinavia

An apparently novel neurological disease clinically characterized by shaking, tremors, seizures, staggering gait, and ataxia was first observed in farmed mink kits in Denmark in 2000 and subsequently in Sweden, Denmark, and Finland in 2001, and again in Denmark in 2002. Lymphoplasmacytic encephalomyelitis was found in the affected kits. The lesions were most severe in the brainstem and cerebellum and consisted of neuronal degeneration and necrosis, neuronophagia, focal and diffuse gliosis, perivascular cuffs formed by lymphocytes, plasma cells and macrophages, and segmental loss of Purkinje cells. Testing was conducted to determine the cause of the disease, including general virological investigations (virus culture, negative-staining electron microscopy, immunoelectron microscopy, polymerase chain reaction for herpesviruses, adenoviruses, pestiviruses, and coronaviruses), tests for specific viral diseases (canine distemper, Borna disease, Louping ill, West Nile virus infection, tick-borne encephalitis, Aleutian disease), tests for protozoa (Toxoplasma gondii, Neospora caninum, Encephalitozoon cuniculi), bacteria (general culture, listeria, Clamydophila psittaci), and intracerebral inoculation of neonatal mice. The results of all these investigations were negative. One group of 3 mink kits inoculated intracerebrally with brain homogenate of affected mink developed clinical signs and histological lesions similar to those observed in naturally infected mink. Based on the histopathological features, it is postulated that the disease is caused by a yet unidentified virus.

Hemiconvulsion-hemiplegia syndrome and primary human herpesvirus 7 infection

We report a case of hemiconvulsion-hemiplegia (HH) syndrome. An 18-month-old female infant had a hemiconvulsion followed by left hemiplegia. Magnetic resonance imaging immediately after the onset of hemiplegia showed high intensity in the right hemisphere in diffusion-weighted images (DWI), while T1- and T2-weighted images were normal. Single photon emission computed tomography showed hypoperfusion of the right hemisphere in the acute phase. Virological analyses proved primary human herpesvirus 7 (HHV-7) infection. DWI are useful for the early evaluation of HH syndrome. Vascular disorders due to HHV-7 infection may have been related to the development of HH syndrome in this patient.

Valacyclovir treatment ameliorates the persistently increased pentylenetetrazol-induced seizure susceptibility in mice with herpes simplex virus type 1 infection

Herpes simplex virus type 1 (HSV-1) is an important pathogen related to epilepsy. We have shown previously that corneal inoculation of mice with HSV-1 causes acute spontaneous behavioral and electrophysiological seizures and increases hippocampal excitability and kainite-induced seizure susceptibility. In this study, we aimed to determine whether early-life HSV-1 infection in mice might cause short- and long-term enhanced susceptibility to pentylenetetrazol (PTZ)-induced seizures and to evaluate whether early antiviral drug therapy was effectively ameliorating this deficit. Seizure threshold was calculated by the latency of onset of the myoclonic jerk, generalized clonus, and maximal tonic-clonic convulsion. We demonstrate that the localization of viral antigens was predominantly within the bilateral temporal areas (amygdala, piriform, and entorhinal cortex) of HSV-1-infected mice. We also present evidence that mice of all HSV-1-infected groups had a shorter latency and higher severity to PTZ-induced seizures than in age-matched, mock-infected controls. Treatment of HSV-1-infected mice with valacyclovir, a potent inhibitor of HSV-1 replication, produced a dose-dependent decrease in the signs of neurological deficits, pathological damages, and PTZ-induced seizure severity. Our results are consistent with the hypothesis that early-life HSV-1 infection leads to persistent enhancement of neuronal excitability in limbic circuits, which could result in an overall increased propensity to induce seizures later in life. Additionally, prompt optimal antiviral therapy effectively decreases seizure susceptibility in HSV-1-infected mice by limiting the level of viral replication and inflammatory response induced by virus. The present study provides not only experimental evidence, but also a new therapeutic strategy in HSV-1-associated human epilepsy.

Seizure, neuron loss, and mossy fiber sprouting in herpes simplex virus type 1-infected organotypic hippocampal cultures

PURPOSE

Epileptic seizures are frequently seen after viral encephalitis. Herpes simplex virus type 1 (HSV-1) encephalitis is the most common cause of acquired epilepsy in humans. However, little information is available about the neuropathogenesis of HSV-1-associated seizures. We have developed an in vitro HSV-1-infected organotypic hippocampal slice culture to elucidate the underlying mechanisms of HSV-1-associated acute seizure activity.

METHODS

Hippocampal slice cultures were prepared from postnatal day 10 to 12 rat pups. Wild-type HSV-1 strain RE (1 x 10(5) PFU) was applied to cultures at 14 days in vitro. The excitability of CA3 pyramidal cells and hippocampal network properties were measured with electrophysiological recordings. Hematoxylin-eosin (H&E) and Timm stains were used.

RESULTS

HSV-1 infection induces epileptiform activity, neuron loss, and subsequently a dramatic increase of mossy fiber sprouting in the supragranular area. With intracellular recordings, surviving CA3 pyramidal cells exhibited a more depolarizing resting membrane potential concomitant with an increase in membrane input resistance and had a lower threshold to generate synchronized bursts and a decrease in the amplitude of afterhyperpolarization than did controls. When the antiherpes agent acyclovir was applied with a delay of 1 or 24 h after HSV-1 infection, a dramatic inhibition of HSV-1 replication and protection of the neuron loss were observed.

CONCLUSIONS

These results suggest that a direct change in the excitability of the hippocampal CA3 neuronal network and HSV-1-induced neuron loss resulting in subsequent mossy fiber reorganization may play an important role in the generation of epileptiform activity.

Epilepsy, CNS viral injury and dynorphin

Epilepsy is a significant health problem. Despite the widespread use of both classic and newer pharmacological agents that target ion channels, amino acid transmission or receptors, there are numerous examples of mono- or polytherapy being ineffective. Seizures that are secondary to CNS infections are among the most refractory medically, and thus insult-specific agents are desirable. Recently, the study of the neuropharmacological actions of dynorphin in CNS viral injury has yielded new insights into epileptogenesis and epilepsy treatment. The opioid neuropeptide dynorphin modulates neuronal excitability in vitro in hippocampal slices and potentiates endogenous anti-ictal (i.e. protective) processes in animal models and humans. This work has renewed interest in the role of dysregulation of dynorphin in the pathogenesis of refractory seizures, including encephalitic seizures. The important role of dynorphin in epilepsy is also supported by new models of symptomatic epilepsies based on viral-induced seizures.

Frontal lobe seizures and uveitis associated with acute human parvovirus B19 infection

We report a 5-year-old girl who developed repeated episodes of behavioral alterations shortly after human parvovirus B19 infection and uveitis. Video-electroencephalographic study demonstrated that these brief episodes were frontal lobe seizures. Seizures responded promptly to antiepilepsy medications. Further diagnostic testing did not reveal any rheumatologic disorders. Human parvovirus B19 infections in children are more commonly associated with febrile seizures and meningoencephalitis. Our case demonstrates that, rarely, it may be associated with the development of partial epilepsy.

Recombinant AAV-mediated expression of galanin in rat hippocampus suppresses seizure development

Galanin, a 29- or 30-amino acid neuropeptide, has been implicated in the modulation of seizures. In this study, we constructed a recombinant adeno-associated viral (AAV) vector to constitutively over-express galanin (AAV-GAL). The vector mediated efficient transduction of HEK 293 cells in vitro and robust galanin expression in vivo when injected into the rat dorsal hippocampus. Rats were administered kainic acid intrahippocampally 2.5 months following AAV-GAL or empty vector (AAV-Empty) injection to study the effect of vector-mediated galanin over-expression on seizures. AAV-GAL-injected rats showed a decreased number of seizure episodes and total time spent in seizures compared to AAV-Empty rats, despite similar latencies to development of the first EEG seizure and similar levels of neuronal damage in the CA3 region for both groups. These data show that recombinant AAV mediates strong and stable over-expression of galanin when injected into the rat hippocampus resulting in a significant anticonvulsive effect. The seizure suppression effect of galanin expression in the hippocampus by viral vectors may lead to novel therapeutic strategies for the treatment and management of intractable seizures with focal onset such as temporal lobe epilepsy.

Congenital infection with human herpesvirus 6 variant B associated with neonatal seizures and poor neurological outcome

Human herpesvirus 6 (HHV 6) has neurotropic and neuroinvasive properties. The virus has been found in the cerebrospinal fluid of many children with aseptic meningoencephalitis. Intrauterine transmission has been documented by HHV 6 DNA detection in cord blood specimens of apparently healthy newborns and in fetuses following spontaneous abortions. A patient is described with early neonatal afebrile seizures resulting from a congenital HHV 6 variant B infection disclosed by repeated detection of viral genome by polymerase chain reaction (PCR) in cerebrospinal fluid in the first days of life. At follow-up, magnetic resonance imaging (MRI) studies disclosed hyperintensities in the periventricular white matter and basal ganglia, associated with cerebral atrophy. Further follow-up at 18 months revealed poor neurological outcome with mild neurodevelopmental retardation, strabismus and hypertonia of legs. This report provides evidence of neurological involvement after HHV 6 vertical transmission, and the association with neurological sequelae.

Transient cerebral arteriopathy in infancy associated with enteroviral infection

We report the case of an 18-month-old boy who presented aphasia and right hemiplegia of acute onset. The neurological deficit completely resolved after a few hours, but identical transient neurological deficits and seizures occurred during the following days. Imaging showed proximal stenosis of the medial cerebral artery and deep ischaemic lesions in the territory of this artery. Analysis of the cerebrospinal fluid showed pleocytosis and an active enteroviral infection with positive RNA detection. The evolution was consistent with transient cerebral arteriopathy of childhood as magnetic resonance angiography showed normalization of the arterial lesions. This is the first report of an enteroviral infection associated with this entity. We want to stress the importance of performing a cerebrospinal fluid analysis when an ischaemic stroke of unclear aetiology occurs in a child.

Encephalitis related to primary varicella-zoster virus infection in immunocompetent children

INTRODUCTION

Encephalitis is a rare complication of primary varicella-zoster virus (VZV) infection in immunocompetent children.

METHODS

The clinical and laboratory findings of two girls with VZV-related encephalitis are reported.

RESULTS

Both children presented with focal epileptic seizures, corresponding to cortical/subcortical as well as white matter lesions. The first showed a typical vesicular skin rash. She was easily diagnosed and made a rapid recovery during acyclovir and steroid treatment. In the second girl, a preceding measles-mumps-rubella virus vaccination and the absence of skin vesicles were misleading with respect to the diagnosis, which was finally proven by IgG seroconversion and intrathecal synthesis of IgG antibodies to VZV. She developed left parieto-occipital tissue necrosis and recovered only transiently during initial acyclovir/steroid treatment. Eight weeks after onset, progressive white matter demyelination and the occurrence of erythema nodosum in the lower limbs necessitated a second 4-month course of oral steroids. The VZV PCR from cerebrospinal fluid was negative in both children.

CONCLUSIONS

Primary VZV infection may cause severe encephalitis that may occur without skin vesicles and lead to a chronic course with systemic vasculitis. The coincidence of vaccination and neurologic diseases offers no proof per se of a causal relationship.

Case report: primary human herpesvirus-6 associated with an afebrile seizure in a 3-week-old infant

We describe a 3-week-old male infant with an afebrile seizure in whom serologic and polymerase chain reaction (PCR) findings support concomitant primary human herpesvirus 6 (HHV-6) infection. Although HHV-6 infection has been associated with first-time febrile seizures and encephalitis in both immunocompetent and immunocompromised hosts, it has not been associated previously with afebrile seizures in healthy infants. This report provides additional evidence of the neuropathogenic potential of HHV-6.

Lassa fever encephalopathy: Lassa virus in cerebrospinal fluid but not in serum

The pathogenesis of neurologic complications of Lassa fever is poorly understood. A Nigerian patient had fever, disorientation, seizures, and blood-brain barrier dysfunction, and Lassa virus was found in cerebrospinal fluid (CSF) but not in serum. The concentration of Lassa virus RNA in CSF corresponded to 1 x 10(3) pfu/mL, as determined by a quantitative real-time polymerase chain reaction assay. To characterize the Lassa virus in CSF, the 3.5-kb S RNA was sequenced. In the S RNA coding sequences, the CSF strain differed between 20% and 24.6% from all known prototype strains. These data suggest that Lassa virus or specific Lassa virus strains can persist in the central nervous system and thus contribute to neuropathogenesis. Lassa virus infection should be considered in West African patients or in travelers returning from this area who present only with fever and neurologic signs.

Congenital varicella-zoster virus infection after maternal subclinical infection: clinical and neuropathological findings

OBJECTIVE

It is known that varicella-zoster virus (VZV) can cause asymptomatic infections, but it has not been described that congenital infection can be caused by maternal subclinical infection. The purpose of this study is to evaluate clinical and neuropathologic findings of infants with neonatal seizures and cerebrospinal fluid (CSF) VZV antibodies, but no maternal clinical VZV infection during the pregnancy.

STUDY DESIGN

Screening of 201 neonates were studied for congenital viral infections, because of neurologic problems of unknown origin. Antibodies to 16 different microbes were investigated from the CSF and the serum of the neonates, as well as from the first trimester and postpartum serum of their mothers. Clinical symptoms and signs as well as neuropathology of those infants with antibodies to VZV in CSF were evaluated in this study.

RESULTS

Four neonates with antibodies to VZV in CSF were identified and CSF findings were reported earlier. Their mothers had laboratory evidence of infection, based on a significant rise in serum VZV antibody level during pregnancy in three mothers, and a constantly high antibody level to VZV in one mother. All four children had seizures and abnormalities in muscular tone during the neonatal period, but no typical manifestations of a congenital VZV infection. One child died at the age of 4 months. At autopsy, neuropathologic examination showed foci of astrocytic hyperplasia and hypertrophy but no specific signs of viral infection.

CONCLUSION

Maternal subclinical VZV infection can cause congenital infection with neurologic symptoms and signs in the child.

Enteroviral meningoencephalitis in immunocompromised children after matched unrelated donor-bone marrow transplantation

Two children are described who presented with fever and generalized seizures, days 50 and 200, respectively, after matched unrelated donor-bone marrow transplantation. Upon antiepileptic treatment the seizures vanished but somnolence and fever remained. Magnetic resonance imaging (MRI) of the brain was performed and revealed transient asymmetric multifocal hyperintense lesions. Seizures were considered related to infection, and the cyclosporin A (CsA) treatment was not interrupted. Enterovirus was detected by reverse transcriptase-polymerase chain reaction in the spinal fluid of one patient and in the sputum of the other. Both children recovered completely within the next weeks without neurological sequel. This report shows that enteroviral meningoencephalitis can present with seizures during the post-transplant period. It highlights the importance of MRI for neuroimaging and of viral infections as differential diagnosis to CsA neurotoxicity.

HIV infection and seizures

New-onset seizures are frequent manifestations of central nervous system disorders in patients infected with human immunodeficiency virus (HIV). Seizures are more common in advanced stages of the disease, although they may occur early in the course of illness. In the majority of patients, seizures are of the generalised type. Status epilepticus is also frequent. Associated metabolic abnormalities increase the risk for status epilepticus. Cerebral mass lesions, cryptococcal meningitis, and HIV-encephalopathy are common causes of seizures. Phenytoin is the most commonly prescribed anticonvulsant in this situation, although several patients may experience hypersensitivity reactions. The prognosis of seizure disorders in HIV-infected patients depends upon the underlying cause.

Stroke and seizures as the presenting signs of pediatric HIV infection

The authors report two pediatric patients with definite human immunodeficiency virus infection whose initial presentation was stroke and seizure. The first patient was a 3-year-old female who developed acute hemiparesis as the first manifestation. The other, a 2-month-old infant, had focal seizures secondary to cerebral infarction. Investigations revealed ischemic infarction of the thalamus, hypothalamus, and internal capsule in the first patient and cerebral cortex in the second. Further investigations failed to demonstrate any other causes of these cerebral infarctions. Opportunistic infection of the central nervous system was not documented. The authors emphasize that cerebrovascular accident may be the initial presentation in human immunodeficiency virus infection in children. Human immunodeficiency virus infection must be included in the differential diagnosis, and testing for the disease is mandatory in the investigation of stroke in any child who is at risk of having this infection.

Human herpesvirus-6: neurologic implications of a newly-described viral pathogen

Discovered only 12 years ago, human herpesvirus-6 (HHV-6) has been associated with central nervous system (CNS) findings such as febrile seizures, encephalitis, meningitis, and possibly multiple sclerosis. These manifestations have been reported in both immunocompetent and immunocompromised individuals. The applications of such sophisticated laboratory tools as polymerase chain reaction, in situ hybridization, immunohistochemical staining, and representational difference analysis have expanded knowledge of the spectrum of CNS disease attributable to HHV-6 while delineating pathogenic mechanisms of both primary HHV-6 infection and reactivation from latency. This article reviews existing knowledge of the CNS manifestations of HHV-6, focusing on both clinical aspects of HHV-6 infection and its pathogenesis on neurologic diseases.

Antibodies to varicella zoster virus in the cerebrospinal fluid of neonates with seizures

Four neonates with convulsions had IgG antibodies in their cerebrospinal fluid (CSF) to varicella zoster virus (VZV). These antibodies were found in the sera of two of these patients after the age of 6 months. Antibodies to 16 different microbes were studied from the serum and CSF of 201 neonates with neurological problems. The presence of DNA specific to HSV-1, HSV-2, and VZV in the CSF was also investigated using the polymerase chain reaction (PCR). Antibodies to VZV were detected in the CSF of four neonates. Antibody indices suggested production of VZV specific antibodies in the central nervous system. These findings suggest that intrathecal production of antibodies to VZV can appear in neonates with neurological problems, which suggests that intrauterine VZV infection can be acquired without cutaneous symptoms in the mother.

California encephalitis in Alabama

Arthropod-borne virus (arbovirus) infections in humans are primarily central nervous system infections, but other clinical manifestations include febrile illness and fever with hemorrhagic diathesis. In the genus Bunyavirus there are several viruses that cause disease in humans, especially in North America; these include LaCrosse, Jamestown Canyon, trivittatus, and snowshoe hare viruses. The disease seen mainly in children is California encephalitis (usually of the LaCrosse subtype); this infection is widespread in the United States but is most prevalent in the upper Midwest, especially in rural areas. We present the first reported case of California encephalitis in rural Alabama; the patient was a 7-year-old boy who came to us with fever and seizures in the summer of 1994. This report stresses the importance of including California encephalitis in the differential diagnosis when children have fever and altered sensorium after exposure to mosquitoes during summer months.

Pathology of chronic herpes infection associated with seizure disorder: a report of two cases with tissue detection of herpes simplex virus 1 by the polymerase chain reaction

Although uncommon, the association of chronic encephalitis with epilepsy is well recognized. While a viral etiology has been suspected based on the morphology, to date no virus has been successfully cultured from the brain in patients with Rasmussen's encephalitis. We describe the pathologic findings and report the detection of herpes simplex virus 1 (HSV1) in the brain in two patients who presented primarily with intractable seizures. In the first patient, an intrauterine infection was suspected as the underlying basis for the seizure disorder and the extensive cerebral calcification and gliosis. The second patient (with presumed HSV1 encephalitis at age 7 months) underwent a temporal lobectomy for medically refractory seizures at the age of 3 years and pathologic examination revealed a chronic encephalitis. While immunohistochemical, ultrastructural, and culture studies were negative for viral pathogens, molecular analysis by the polymerase chain reaction (PCR) revealed HSV1 DNA sequences in both cases. Thus our cases represent two examples of chronic encephalitis associated with a seizure disorder, where a definitive viral etiology was documented by PCR.

Neuroinvasion and persistence of human herpesvirus 6 in children

Human herpesvirus 6 (HHV-6) causes a febrile illness in children and has been implicated as a cause of encephalitis and recurrent seizures. Paired samples of cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMC) from 487 children were evaluated by nested polymerase chain reaction (PCR) for evidence of current or past infection with HHV-6. PBMC were also cultured for isolation of HHV-6. These data were correlated with the patients' clinical information. HHV-6 DNA was detected in 72 (14.8%) of 487 CSF samples. HHV-6 persistence was documented in 142 children by PCR detection of HHV-6 DNA in PBMC or CSF (or both) in the absence of primary HHV-6 infection; the central nervous system was the only site of HHV-6 DNA persistence in 28.9%. HHV-6 DNA can be detected in the CSF of children during and after primary infection, and the central nervous system may be the sole site of persistence.