Predictive value of serum interleukin-6 level in influenza virus-associated encephalopathy

Clinical and MRI features of neurological complications after influenza A (H1N1) infection in critically ill children

BACKGROUND

Influenza A (H1N1) can cause severe neurological complications.

OBJECTIVE

The purpose of this study was to analyze clinical and MRI features of neurological complications after H1N1 infection in critically ill children.

MATERIALS AND METHODS

We retrospectively analyzed clinical and neuroimaging findings in 17 children who were hospitalized in an intensive care unit with severe neurological complications after H1N1 infection in South China between September 2009 and December 2011. All children underwent pre- and post-contrast-enhanced brain MRI. Postmortem studies were performed in two children.

RESULTS

Six children died, five because of acute necrotizing encephalopathy (ANE) and one because of intracranial fungal infection. Eleven recovered; their manifestations of H1N1 were meningitis (3), encephalitis (1) and influenza encephalopathy (7). MRI features of ANE included multiple symmetrical brain lesions demonstrating prolonged T1 and T2 signal in the thalami, internal capsule, lenticular nucleus and pontine tegmentum. Postmortem MRI in two children with acute necrotizing encephalopathy showed diffuse prolonged T1 and T2 signal in the bilateral thalami, brainstem deformation and tonsillar herniation.

CONCLUSION

Fatal neurological complications in children after H1N1 infection include ANE and opportunistic fungal infection. MRI is essential for identification of neurological complications and for clinical evaluation.

Neurological and muscular manifestations associated with influenza B infection in children

BACKGROUND

Influenza viruses have been associated with various neurological and muscular symptoms. The aim of this study was to evaluate the pediatric neurological and muscular manifestations of influenza B during a 5-month epidemic at a single center.

METHODS

We retrospectively reviewed the medical records of 355 pediatric patients with laboratory-confirmed influenza B infection.

RESULTS

Neurological and muscular symptoms were exhibited by 28 patients (7.9%). The mean age was 48.7 ± 25.2 months. The mean time between respiratory symptoms and neurological symptoms was 2.2 ± 1.5 days. The most common symptom was seizure (19/28, 67.9%), followed by myositis (5/28, 17.9%), increased intracerebral pressure (1/28, 3.6%), delirium (1/28, 3.6%), and severe headache (1/28, 3.6%). There was one severe case of meningitis with myocarditis (1/28, 3.6%). All seizures were febrile: 15 simple febrile seizures (78.9%), three complex febrile seizures (15.8%), and one febrile status epilepticus (5.3%). The mean age of nine patients with their first seizures was 37.9 ± 22.2 months, which was older than the typical age of onset for febrile seizure. All the patients, except one, were treated with oseltamivir. There were no deaths or chronic debilitating sequelae.

CONCLUSIONS

The neurological and muscular complications of influenza B infection in children are relatively mild, and febrile seizure is the most common. However, clinicians should be alert to the possibility of rare severe complications during influenza B outbreaks.

Systemic inflammatory response syndrome and prolonged hypoperfusion lesions in an infant with respiratory syncytial virus encephalopathy

Respiratory syncytial virus (RSV) is a cause of neurological complications in infants. We report a rare case of RSV encephalopathy in an infant who presented with poor sucking and hypothermia at 17 days of age after suffering from rhinorrhea and a cough for several days. After hospitalization, the patient presented with stupor and hypotonia lasting for at least 24 h, and was intubated, sedated, and ventilated for treatment of pneumonia. These symptoms led to diagnosis of pediatric systemic inflammatory response syndrome (SIRS) caused by RSV infection. High-dose steroid therapy was combined with artificial ventilation because the initial ventilation therapy was ineffective. Interleukin (IL)-6 levels in spinal fluid were markedly increased upon admission, and serum IL-6 and IL-8 levels showed even greater elevation. The patient was diagnosed with RSV encephalopathy. On day 5, high signal intensity in the bilateral hippocampus was observed on diffusion-weighted magnetic resonance imaging (MRI). On day 14, the patient presented with delayed partial seizure and an electroencephalogram showed occasional unilateral spikes in the parietal area, but the hippocampal abnormality had improved to normal on MRI. ^99mTc-labeled ethylcysteinate dimer single-photon emission computed tomography (SPECT) on day 18 showed hypoperfusion of the bilateral frontal and parietal regions and the unilateral temporal region. SPECT at 3 months after onset still showed hypoperfusion of the bilateral frontal region and unilateral temporal region, but hypoperfusion of the bilateral parietal region had improved. The patient has no neurological deficit at 6 months. These findings suggest that RSV encephalopathy with cytokine storm induces several symptoms and complications, including SIRS and prolonged brain hypoperfusion on SPECT.

Human herpesvirus-6 encephalitis during hematopoietic stem cell transplantation leads to poor prognosis

INTRODUCTION

Indications for the application of hematopoietic stem cell transplantation (HSCT) from alternative donors have remarkably broadened in scope; however, the incidence of infections that lead to failure of HSCT, such as human herpesvirus-6 (HHV-6) encephalitis, has also increased.

METHODS

We analyzed risk factors for symptomatic HHV-6 reactivation and the development of HHV-6 encephalitis in 140 consecutive adult patients who received allogeneic HSCT at our institution. Stem cell sources for the recipients were as follows: related-donor bone marrow in 40, related-donor peripheral blood in 5, unrelated bone marrow in 67, and unrelated cord blood in 28.

RESULTS

Symptomatic HHV-6 reactivation occurred in 22 patients (16%), and 11 patients manifested encephalitis. Multivariate Cox proportional hazards regression analysis identified cord blood cell transplantation (CBT) as an independent predictor of HHV-6 reactivation (P = 0.008). Hyponatremia or hypernatremia at the time of HHV-6 reactivation was detected before the development of HHV-6 encephalitis in 2 or 4 patients, respectively. Two patients died of HHV-6 encephalitis and 6 patients died of relapse of underlying diseases. Survival analysis identified higher risk of the disease (P = 0.021) and HHV-6 encephalitis (P = 0.003) as independent risk factors for reduced overall survival.

CONCLUSION

In cases involving CBT or unrelated-donor transplantation, patients should be carefully monitored for the symptomatic reactivation of HHV-6.

Severe form of encephalopathy associated with 2009 pandemic influenza A (H1N1) in Japan

BACKGROUND

Every year, an estimated 200-500 children in Japan develop influenza-associated encephalopathy (IAE), and 10-30% of these children die.

OBJECTIVE

To clarify the clinical features of a severe form of acute encephalopathy seen with 2009 pandemic influenza A (H1N1).

STUDY DESIGN

This retrospective survey examined 20 children with acute encephalopathy associated with the 2009 pandemic influenza A (H1N1) who died or were in a prolonged deep coma with a flat electroencephalogram tracing and loss of spontaneous respiration. We obtained demographic, clinical, laboratory, and neuroimaging data through interviews with the attending physicians and chart reviews.

RESULTS

Subjects were 13 boys and seven girls. Their median age was 45 (range 11-200) months. Five patients had one or more pre-existing conditions. Acute encephalopathy developed within 2 days after influenza onset in 16 patients. As the initial neurological symptom, delirious behavior was seen in six children, and brief seizures in six. Eighteen patients were comatose within 6h of the onset of encephalopathy. Marked brain edema on computed tomography (CT) was seen in all but one patient. Brainstem lesions on CT were recognized in 12 patients. Sixteen patients died 0-45 (median 2.5) days after the onset of acute encephalopathy, and the others remained in deep comas without spontaneous respiration.

CONCLUSIONS

The clinical course of the patients was characterized by an onset with mild neurological symptoms and rapid deterioration of consciousness into coma. Head CT revealed marked cerebral edema, often associated with brainstem lesions.

Post-marketing assessment of neuropsychiatric adverse events in influenza patients treated with oseltamivir: an updated review

A 2008 review by our group concluded that the risk of neuropsychiatric adverse events (NPAEs) in influenza patients was not increased by oseltamivir exposure, and did not identify any mechanism by which oseltamivir or its metabolites could cause or worsen such events. The current article reviews new information on this topic. Between September 16, 2007 and May 15, 2010, 1,805 spontaneously-reported NPAEs were identified in 1,330 patients receiving oseltamivir: 767 (42.5%) from Japan, 296 (16.4%) from the USA, and 742 (41.1%) from other countries. NPAEs were more common in children: 1,072 (59.4%) events were in those aged ≤16 years. NPAEs often occurred within 48 h of treatment initiation (953 events; 52.8%). Nearly half of the events were serious in nature (838; 46.4%). The three largest categories of events were abnormal behavior (457 events, 25.3%), miscellaneous psychiatric events (370; 20.5%), and delusions/perceptual disturbances (316 events, 17.5%). A total of 1,545 events (85.6%) in eight different categories were considered to be delirium or delirium-like. Twenty-eight suicide-related events were reported. A US healthcare claims database analysis showed that the risk of NPAEs in 7,798 oseltamivir-treated patients was no higher than that in 10,411 patients not on antivirals, but a study on oseltamivir and abnormal behavior in Japan was less conclusive. NPAE frequency in oseltamivir-exposed Japanese and Taiwanese children with influenza was the same as in unexposed children. New analysis of the UK General Practice Research Database showed that the relative adjusted risk of NPAEs in influenza patients was 2.18-times higher than in the general population. Other epidemiology studies report frequent occurrence of encephalitis and similar disorders in influenza patients independently of oseltamivir exposure. The new data support the findings of the original assessment. Evidence suggests that influenza-related encephalopathies are caused by influenza-induced inflammatory responses, but more work is needed to confirm the underlying mechanisms.

Prognostic factors in acute encephalopathy with reduced subcortical diffusion

OBJECTIVES

Acute encephalopathy with reduced subcortical diffusion (AED) covers a spectrum including not only typical acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) but also atypical AESD with monophasic clinical course, or more severe subtypes. Aim of this study is to analyze prognostic factors of AED.

MATERIALS & METHODS

We recruited 33 children with AED, that is, widespread diffusion restriction in cortical and subcortical structures. Their clinical courses, laboratory data, MRI, and the efficacy of treatment were analyzed retrospectively.

RESULTS

Of the 33 children, 20 were males and the mean age at diagnosis was 22 months. Eighteen children had good outcome and 15 had poor outcome. Univariate analysis showed loss of consciousness 24 h after the onset, prolonged seizure at the onset, and mechanical ventilation to be weak predictors of poor outcome. Maximal aspartate aminotransferase, alanine aminotransferase, and creatinine kinase levels were significantly higher in the poor outcome group. Multivariate analysis showed loss of consciousness 24 h after the onset and prolonged seizure at the onset to be poor predictors of AED. Treatment with steroids and/or immunoglobulins did not result in better outcome.

CONCLUSION

Prolonged seizure at the onset and loss of consciousness 24 h after the onset were seen at early stages of severe AED. Using these features, a prospective study of early intervention in AED should be conducted to further analyze the efficacy of its treatment.

Production of chemokines in respiratory syncytial virus infection with central nervous system manifestations

Respiratory syncytial virus (RSV) infection in children can be associated with acute encephalopathy. However, the roles of cytokines in the cerebrospinal fluid (CSF) of such patients remain unevaluated. In this study, a profile of 17 cytokines was determined for eight RSV-infected children with neurological complications. In one patient with high levels of 13 cytokines, a cytokine storm was considered to have occurred. Interleukin (IL)-6, IL-8, monocyte chemoattractant protein (MCP)-1, and macrophage inflammatory protein (MIP)-1β levels were also high in other patients. These data suggest that chemokines in CSF play roles in neurological complications in RSV-infected children.

High doses of oseltamivir phosphate induce acute respiratory arrest in anaesthetized rats

It has been reported that one of the serious adverse events after the treatment of oseltamivir phosphate (OP) for influenza patients is sudden death resulting from cardiorespiratory arrest. To investigate the aetiology of such an adverse consequence, we examined effects of OP (expressed as free base) on blood pressure and ventilation in anaesthetized rats with vagotomy. Intravenous OP (30-200 mg/kg) caused dose-dependent hypotension and bradycardia in spontaneously breathing animals. Concomitantly with changes in blood pressure, the tracheal airflow increased. The ventilatory rate hastened during the injection and then transiently slowed around 1 min. after the administration (transient hypopnea). Thereafter, it gradually returned to control. The hypopnea increased with increasing dose and ventilatory arrest occurred at 200 mg/kg. Intraduodenal OP (500-1000 mg/kg) provoked cardioventilatory arrest 72-218 min. after the injection. Oseltamivir carboxylate (100-200 mg/kg, i.v.), an active metabolite of OP, had no significant effect on ventilation and blood pressure. In artificially ventilated animals, intravenous OP caused slowing of the respiratory rate around 1 min. after the injection in a dose-dependent manner. This effect of OP waned in 5 min. after the administration. The amplitude of phrenic nerve discharge was not changed at lower doses (30-100 mg/kg). The phrenic nerve stopped to discharge immediately after higher doses (150-200 mg/kg). We demonstrated that OP causes central suppression of the respiratory function in rats and suggest a relationship between the OP-induced cardiorespiratory arrest and sudden death observed in influenza patients after taking OP.

Therapeutic efficacy of Hypericum perforatum L. extract for mice infected with an influenza A virus

Hypericum perforatum L., a plant used in Chinese herbal medicine, has been proven effective against many viral diseases. In the present study, the therapeutic efficacy of an extract of H. perforatum (HPE) against influenza A virus (IAV) was investigated in mice. Whether HPE would be a promising agent for influenza treatment was evaluated by measuring the protection rate, mean survival days, lung index, and viral titer, as well as the secretion of IL-6, interleukin-10 (IL-10), tumour necrosis factor-α (TNF-α), and interferon-gamma (IFN-γ) in lung tissue and serum on days 3 and 5 post-infection. The results showed that HPE could reduce the lung index and viral titer of mice infected with IAV, decrease mortality, and prolong the mean survival time. HPE decreased the concentration of IL-6 and TNF-α in lung tissue and serum on day 5 post-infection. In contrast, HPE enhanced the lung and serum levels of IL-10 and IFN-γ on the days 3 and 5 post-infection. Our study indicates that HPE has significant therapeutic efficacy for mice infected with IAV. The possible reasons for these results were concluded to be pertaining to up-regulating the expression of IL-10 and IFN-γ, and down-regulating the secretion of IL-6 and TNF-α in lung and serum.

Classification of acute encephalopathy in respiratory syncytial virus infection

Infection with respiratory syncytial virus (RSV) is known to be associated with central nervous system symptoms such as convulsions. We investigated cytokines, nitrogen oxide (NO)( x ), and the viral genome in cerebrospinal fluid (CSF) obtained from children with RSV infection-related convulsions or central nervous symptoms and compared the data with type of encephalopathy. Of nine patients enrolled (six boys and three girls; aged 10 days-3 years), one metabolic error, five excitotoxicity, one cytokine storm, and two hypoxia cases were found. The patients presented with unilateral convulsions, generalized convulsions, and convulsions following cardiopulmonary arrest, apnea, and nuchal rigidity. In all patients, a rapid check for RSV of nasal fluid was positive. The RSV genome (subgroup A) was detected in the CSF of five of the nine patients; two patients with hypoxic encephalopathy were negative for the RSV genome. The CSF interleukin (IL)-6 levels were high only in patients with the excitotoxicity and cytokine storm type of encephalopathy. NO( x ) levels were high in all the subject cases. In the excitotoxicity type, NO( x ) levels were significantly higher than those in the control and other groups. NO( x ) level may become an important parameter for the diagnosis and classification of acute encephalopathy in RSV. Strategies to treat each type of encephalopathy, targeting cytokines and free radicals, should be established.

Serum and cerebrospinal fluid cytokine profile of patients with 2009 pandemic H1N1 influenza virus-associated encephalopathy

PURPOSE

Since April 2009, the number of patients with 2009 pandemic H1N1 influenza virus infection has been increasing in Japan just as in the rest of the world. Patients with 2009 pandemic H1N1 influenza-associated encephalopathy (pIE) have also been reported. The common clinical symptoms of this condition are seizures and progressive coma with high-grade fever. We previously reported the possible association between seasonal influenza-associated encephalopathy (sIE) and proinflammatory cytokines. However, the pathogenesis of pIE remains to be elucidated.

RESULTS

In pIE patients with a poor outcome, the serum levels of interleukin (IL)-6, IL-10, and soluble tumor necrosis factor (TNF) receptor (sTNFR1) were significantly higher than those in pIE patients without neurological sequelae. Similarly, the cerebrospinal fluid (CSF) IL-6 levels in pIE patients with a poor outcome were significantly higher than those in pIE patients without neurological sequelae.

CONCLUSION

Our results suggest that IL-6, TNF-α, and IL-10 play important roles in pIE, and that the serum levels of IL-6, IL-10, and sTNFR1 and the CSF levels of IL-6 are related to neurological complications.

Hospitalized children with 2009 influenza a (H1N1) infection in Shenzhen, China, November-December 2009

OBJECTIVES

During the winter outbreak of 2009 influenza A (H1N1) infection in China, the number of confirmed cases and the fatal cases has grown rapidly. We describe the clinical characteristics of hospitalized children with 2009 influenza A (H1N1) infection in Shenzhen, China, November-December 2009.

METHODS

Using a standardized form, we collected data on 148 hospitalized children. 2009 influenza A (H1N1) infection was confirmed in nasopharyngeal swab specimens with the use of a real-time reverse transcriptase-polymerase chain reaction assay.

RESULTS

Of the 148 hospitalized children with 2009 influenza A (H1N1) infection, 81 (55%) were 5 years of age or older and 85% of the patients were previously healthy. The common presenting symptoms were fever (94%), cough (89%), runny nose (36.5%), vomiting (24%), sore throat (19.6%), wheezing (18%), abdominal pain (16%), mental status changes (9%), seizures (6%), diarrhea (6%), myalgia (6%), and chest pain (4%). Twenty-nine (20%) patients were admitted to an ICU, 10 (7%) patients required mechanical ventilation. The overall complication rate was 65.5%, they were pneumonia in 94 (64%), neurologic complications in 18 (12%), parapneumonic effusion in 12 (8%) and myocarditis in 7 (5%). One hundred seven (72%) patients received oseltamivir treatment, 34 (23%) received within 48 hr after the onset of symptoms. All patients received antibiotics before admission or on admission. One hundred forty-four (97%) patients were discharged; four (3%) previously healthy patients died, three died from severe encephalopathy, one died from secondary fungal meningitis.

CONCLUSION

Hospitalized children with 2009 influenza A (H1N1) infection can have a wide range of presentation and clinical complications including neurologic complications. The severe cases and deaths concentrate in previously healthy older children.

A brain slice culture model of viral encephalitis reveals an innate CNS cytokine response profile and the therapeutic potential of caspase inhibition

Viral encephalitis is a significant cause of human morbidity and mortality in large part due to suboptimal diagnosis and treatment. Murine reovirus infection serves as a classic experimental model of viral encephalitis. Infection of neonatal mice with T3 reoviruses results in lethal encephalitis associated with neuronal infection, apoptosis, and CNS tissue injury. We have developed an ex vivo brain slice culture (BSC) system that recapitulates the basic pathological features and kinetics of viral replication seen in vivo. We utilize the BSC model to identify an innate, brain-tissue specific inflammatory cytokine response to reoviral infection, which is characterized by the release of IL6, CXCL10, RANTES, and murine IL8 analog (KC). Additionally, we demonstrate the potential utility of this system as a pharmaceutical screening platform by inhibiting reovirus-induced apoptosis and CNS tissue injury with the pan-caspase inhibitor, Q-VD-OPh. Cultured brain slices not only serve to model events occurring during viral encephalitis, but can also be utilized to investigate aspects of pathogenesis and therapy that are not experimentally accessible in vivo.

The interplay of infection and genetics in acute necrotizing encephalopathy

PURPOSE OF REVIEW

Acute necrotizing encephalopathy (ANE) presents with fulminant encephalopathy and characteristic brain lesions following viral infection. The rarity and unpredictability of the disorder have significantly impaired its study. Growing recognition of ANE and the discovery of causative missense mutations in the nuclear pore gene RANBP2 give promising steps toward unraveling this disease. This review summarizes recent advances of clinical and scientific understanding of ANE.

RECENT FINDINGS

Inflammatory factors participate in the pathogenesis of ANE, but the lack of difference between influenza and noninfluenza ANE focuses attention on the abnormal host response as causative. Early treatment with steroids provides the best outcome for patients who do not have brainstem lesions. Missense mutations in RANBP2 cause the majority of familial and recurrent ANE cases, but other single-gene causes of ANE are possible for familial, recurrent, and sporadic cases.

SUMMARY

Early recognition and systematic evaluation of ANE are necessary. Modeling ANE as a genetic disorder may provide the most immediate gains in the understanding and treatment of ANE and related disorders.

Acute necrotizing encephalopathy during novel influenza A (H1N1) virus infection

A novel swine-origin influenza A (H1N1) virus was recently identified in Mexico. Some cases of infection with neurological complications have been reported to date. We report a case of acute necrotizing encephalopathy associated with the novel H1N1 virus in a 2-year-old European girl who suddenly developed fever, seizures, and altered mental status. Brain and spinal cord magnetic resonance imaging showed bilateral symmetrical lesions of the insulae, thalami, geniculate bodies, and pons tegmentum suggestive of an acute necrotizing encephalopathy. An involvement of meninges and spinal cord was observed configuring an acute necrotizing meningoencephalomyelitis.

Acute encephalopathy and encephalitis caused by influenza virus infection

PURPOSE OF REVIEW

Influenza-associated acute encephalopathy/encephalitis (IAE) is an uncommon but serious complication with high mortality and neurological sequelae. This review discusses recent progress in IAE research for a better understanding of the disease features, populations, outcomes, diagnosis, and pathogenesis.

RECENT FINDINGS

In recent years, many IAE cases were reported from many countries, including Japan, Canada, Australia, Austria, The Netherlands, United States, Sweden, and other countries and regions. During the novel influenza A/H1N1 pandemic, many IAE cases with A/H1N1 infection in children were reported, particularly in those hospitalized with influenza infection. Pathogenesis of IAE is not fully understood but may involve viral invasion of the CNS, proinflammatory cytokines, metabolic disorders, or genetic susceptibility. An autosomal dominant viral acute necrotizing encephalopathy (ANE) was recently found to have missense mutations in the gene Ran-binding 2 (RANBP2). Another recurrent ANE case following influenza A infection was also reported in a genetically predisposed family with an RANBP2 mutation.

SUMMARY

Although IAE is uncommon, compared with the high incidence of influenza infection, it is severe. However, this complication is not duly recognized by health practitioners. Recent advances highlight the threat of this complication, which will help us to have a better understanding of IAE.

Acute encephalopathy with biphasic seizures and late reduced diffusion associated with hemophagocytic syndrome

We reported a girl with HHV-6 infection associated with both acute encephalopathy with biphasic seizures and late reduced diffusion, and hemophagocytic syndrome. She had a prolonged convulsion after a one-day history of febrile illness. Cerebrospinal fluid or brain CT showed no abnormalities on admission and her consciousness was recovered on the next day. However, a prolonged seizure and deterioration of consciousness appeared on the sixth day of illness. Diffusion-weighted images revealed marked reduction of water diffusion in the bilateral frontal areas. HHV-6 infection was virologically proven by polymerase chain reaction. She was treated with gamma-globulin, steroid pulse therapy, and brain hypothermia. In addition, decrease in white blood cells and platelet counts, and elevation of liver enzymes and ferritin were noted on the fourth day of illness. Hemophagocytic macrophages were revealed by bone marrow aspiration on the sixth day. Her hematological and blood chemistry abnormalities recovered gradually after steroid pulse therapy. An elevation of interleukin-6, -8, and -10, and tumor necrosis factor in the serum and that of interleukin-4, -6, and-8 in the cerebrospinal fluid were observed at the onset of a late seizure. These facts suggested that hypercytokinemia will be related to the pathogenesis of acute encephalopathy of our patient.

Delirious behavior in children with acute necrotizing encephalopathy

OBJECTIVE

To clarify the features of delirious behavior in patients with acute necrotizing encephalopathy.

METHODS

We retrospectively evaluated the clinical course of 38 children with acute necrotizing encephalopathy diagnosed on the basis of neuroradiological findings. The patients were divided into two groups according to the presence or absence of delirious behavior. We compared clinical features, laboratory data, neuroimaging findings, and outcome between those with and without delirious behavior. In patients with delirious behavior, chronological sequence of neurological symptoms and the characteristics of delirious behavior were investigated.

RESULTS

Delirious behavior was observed in 8 patients. Patient characteristics or most laboratory data on admission were not significantly different between those with and without delirious behavior. Brainstem lesions were more frequent in patients with delirious behavior than in those without. In contrast, lesions in lentiform nuclei, cerebral hemisphere, or cerebellum were relatively more frequent in patients without delirious behavior. It was the initial neurological symptom in 7 of 8 patients. Stupor and seizures were observed after delirious behavior in most patients.

CONCLUSIONS

Delirious behavior was not uncommon in children with acute necrotizing encephalopathy. Brainstem lesions may be related to the development of delirious behavior of children with acute necrotizing encephalopathy.

Outcome of acute necrotizing encephalopathy in relation to treatment with corticosteroids and gammaglobulin

OBJECTIVE

To examine the relation between outcome and treatment with steroids and gammaglobulin in children with acute necrotizing encephalopathy.

METHODS

We retrospectively evaluated the clinical course and outcome of 34 children with acute necrotizing encephalopathy. They were divided into two groups; 17 patients with brainstem lesion and 17 patients without brainstem lesion. Early steroid use was defined as when steroids were administered within 24h after the onset. The outcome was judged as good when a patient had no or mild cognitive impairment and poor when a patient had more severe sequelae, or died.

RESULTS

Among patients without brainstem lesions, the outcome was good in 7 of 12 with early steroid, whereas it was poor in all 5 patients without early steroid. There was no significant difference in sex, age, and laboratory data between patients with and without early steroid. The outcome was not correlated with gammaglobulin treatment. As to patients without brainstem lesions, the outcome was not correlated with early steroid or gammaglobulin treatment.

CONCLUSIONS

Steroid within 24 h after the onset was related to better outcome of children with acute necrotizing encephalopathy without brainstem lesions. Early steroid treatment will be an important option of the treatment for acute necrotizing encephalopathy.

Acute necrotizing encephalopathy: a comparison between influenza and non-influenza cases

The aim of this study was to clarify the difference between influenza and non-influenza cases in clinical symptoms, laboratory and neuroimaging findings, and outcome in children with ANE. We retrospectively studied 22 children with ANE. Eleven of them had virological proof of influenza infection and the other 11 were judged as non-influenza infection. There was no significant difference between influenza and non-influenza cases in sex, antipyretics use and neurological symptoms. Although laboratory data were not different between the two groups, brainstem lesions were relatively more frequent in influenza cases than in non-influenza cases. Outcome was not different between the two groups. The results of our study suggest that the pathogenesis of acute necrotizing encephalopathy will not be dependent on infectious agents.

[Elderly autopsy case of influenza-associated encephalopathy]

Influenza-associated encephalopathy (IAE) usually occurs in children aged <5 years. Adult cases of IAE are very rare and, thus far, no definite adult autopsy case has been reported. Here, we present the first definite adult autopsy case of IAE. A 76-year-old man presented with sudden coma a day after the onset of fever caused by infection with influenza type A virus. Soon after admission, his condition was complicated by DIC, shock, and multiple organ failure, and he was diagnosed with IAE. Oseltamivir administration and steroid pulse therapy were performed but these proved to be ineffective. The patient died about 24 hours after the onset of encephalopathy. The autopsy revealed massive brain edema and diffuse increase of amoeboid glias without inflammatory cell infiltration. Influenza type A/Hong Kong virus (H3) was isolated from his lungs. Serum IL-6 level was extremely high (35,800 pg/ml; normal, 0.221-4.62 pg/ml). The clinical course, and the laboratory and pathological findings of this adult case resembled those of a typical childhood-onset IAE, suggesting the same pathogenesis. During the influenza season, IAE should be taken into account for differential diagnosis in adult patients with altered mental status and fever.

Differences of clinical manifestations according to the patterns of brain lesions in acute encephalopathy with reduced diffusion in the bilateral hemispheres

BACKGROUND AND PURPOSE

The precise clinical characteristics of acute encephalopathy with bilateral reduced diffusion are not fully understood. We compared clinical, laboratory, and neuroimaging findings according to the patterns of brain lesions among children with reduced diffusion in the bilateral hemispheres.

MATERIALS AND METHODS

Nine patients were analyzed. The patterns of brain lesions were divided into diffuse lesions and central-sparing lesions. Diffuse lesions were defined as reduced diffusion in the whole cortex and/or subcortical white matter. Central-sparing lesions were defined as the lack of reduced diffusion in the areas around the bilateral Sylvian fissures. Clinical, laboratory, and neuroimaging findings were compared between groups.

RESULTS

Five patients showed diffuse lesions and 4 showed central-sparing lesions. Coma was significantly more common in patients with diffuse lesions, whereas a biphasic clinical course was more common in those with central-sparing lesions. Outcome was worse in patients with diffuse lesions. Maximal aspartate aminotransferase, alanine aminotransferase, and kinase levels were also significantly higher in patients with diffuse lesions. In 2 patients with diffuse lesions, diffusion-weighted images during the acute phase revealed reduced diffusion in the bilateral frontal and occipital areas, followed by diffuse lesions. No patient with central-sparing lesions showed MR imaging abnormalities during the acute phase.

CONCLUSIONS

Clinical manifestations in patients with diffuse lesions were severe, whereas those in patients with central-sparing lesions were relatively mild.

Normothermic treatment in acute clinical encephalitis: a case report

Introduction

Encephalitis is a common infection of the brain, associated with a high risk of mortality and morbidity despite intensive supportive therapy. This report describes a patient with acute clinical meningoencephalitis who responded dramatically when her body temperature was decreased to normothermia (36 to 37°C) in combination with barbiturate therapy.

Case presentation

A 15-year-old, previously healthy girl presented with a 2-day history of headache and meningeal stiffness and pyrexia. Cranial magnetic resonance imaging showed high-intensity signals in the splenium of the corpus callosum on T2-weighted and diffusion-weighted images. On day 4 of admission, the level of consciousness decreased and ataxic respiration and apnea appeared. After that, fever (body temperature >40°C) developed with remarkable tachycardia. The body temperature was decreased with the use of a forced-air-cooling blanket and head cooling. The core temperature, measured in the bladder, was maintained at between 36 and 37°C for 5 days. During the period of normothermia, thiopental sodium was given continuously for 3 days. After normothermia, the level of consciousness increased without the development of fever, and ventilatory support was withdrawn.

Conclusion

Our experience suggests that normothermic treatment in combination with barbiturate therapy may be an effective option for the management of brain swelling associated with acute meningoencephalitis, particularly when accompanied by a persistent high fever.

Influenza-associated central nervous system dysfunction: a literature review

CONTEXT

Influenza is a viral pathogen that imposes an under-recognized burden of central nervous system (CNS) disease.

OBJECTIVE

To describe the epidemiology, clinical features and etiology of the CNS disease entities associated with influenza.

DATA SOURCES

English-language publications from MEDLINE.

DATA EXTRACTION

Articles were identified using "influenza, human"[Mesh] AND "nervous system diseases"[Mesh] and screened for inclusion based on relevance and scientific rigor.

RESULTS

Febrile seizure is the most frequently encountered influenza-associated CNS complication, with one in five children hospitalized with influenza experiencing one or more events. In most instances, symptoms resolve without neurological sequelae, although the risk for subsequent afebrile seizure may be increased. Influenza-associated encephalitis/encephalopathy is a less common but potentially more serious complication that is widely reported in Japanese populations, although cases from other East Asian countries, North America, and Europe have been described. Clinical manifestations are diverse, and typically involve febrile seizures and abnormal behaviors in mild cases, with rapid evolution through decreased consciousness to coma in severe forms. In cases of serious disease, the prognosis is often poor, with outcomes including death or severe neurological sequelae. Influenza is also a known trigger for a number of rarely encountered, yet often serious, CNS diseases, including the encephalopathic condition of Reye's syndrome, the peripheral neuropathy known as Guillain-Barré syndrome, and the lesser known complaints of Kleine-Levin syndrome and post-encephalitic Parkinson's disease.

CONCLUSIONS

Influenza imposes a sizeable burden of CNS disease. Increased awareness and monitoring of CNS function is indicated, especially in infants and young children.

Acute childhood encephalitis and encephalopathy associated with influenza: a prospective 11-year review

BACKGROUND

Influenza virus infection has been associated with a variety of neurologic complications. The objective of this study was to evaluate prospectively the role of influenza viruses in acute childhood encephalitis/encephalopathy (ACE).

METHODS

All children admitted to the Hospital for Sick Children, Toronto, during an 11-year period with ACE and evidence of acute influenza virus infection were included. Acute influenza virus infection was defined by detection of the organism in the nasopharynx by direct immunofluorescence microscopy or viral culture and/or by a 4-fold or greater rise in complement fixation titer.

RESULTS

A total of 311 children with ACE were evaluated; evidence of influenza infection was detected in 7% (22 of 311). Eight were excluded from the main analysis because of evidence implicating other potential pathogens. Eleven of the 14 included subjects were <5 years of age. A respiratory prodrome was documented in 93% of subjects. In 64% neurologic manifestations developed within 5 days of onset of respiratory symptoms. Neuroimaging abnormalities were more common in children <2 years of age. Neurologic sequelae occurred in more than one-half of subjects.

CONCLUSIONS

In this prospective registry, influenza virus infection was associated with 5% of ACE cases. The majority of children were <5 years of age and the prevalence of neuroimaging abnormalities was higher in children <2 years of age suggesting that younger children are predisposed to the neurologic complications of influenza. An acute rather than a postinfectious process was suggested by the briefness of the respiratory prodrome in most cases.

Subacute encephalopathy: clinical features, laboratory data, neuroimaging, and outcomes

We sought to clarify the clinical, laboratory, neuroradiologic, and neurophysiologic features of the "subacute" subtype of encephalopathy. We retrospectively identified nine patients with subacute encephalopathy out of 97 patients diagnosed as manifesting acute encephalopathy. Neurologic symptoms, clinical course, laboratory data, neuroradiologic and electroencephalographic findings, and outcomes were reviewed through medical records. The median age of patients was 44 months (range, 28-156 months). The initial neurologic sign was a brief seizure in 4, a prolonged seizure in 3, delirious behavior in 1, and a loss of consciousness in 1. Loss of consciousness the next day was subtle in 4, and mild in 5. However, a worsening of consciousness was observed 3-7 days after onset. Laboratory data were unremarkable, and electroencephalography during the early phase found abnormalities in 4 of 7 patients. Magnetic resonance imaging revealed no abnormalities during the early phase, and mild cortical atrophy during the late phase. All but one patient had various degrees of neurologic sequelae. Subacute encephalopathy was characterized by a delayed worsening of neurologic symptoms, mild cortical atrophy on late magnetic resonance imaging, and poor neurologic outcomes. Recognition of this type of acute encephalopathy is important, and a method to promote early diagnosis is desirable.

Reversible splenial lesion in influenza virus encephalopathy

We describe a rare case of clinically mild, influenza-associated encephalopathy with a reversible splenial lesion. A 12-year-old Japanese girl presented with fever and headache, followed by muscle weakness and somnolence. Magnetic resonance imaging on day 4 of her illness showed a solitary lesion of the splenium of the corpus callosum that was most prominently visualized on diffusion-weighted images. The patient was diagnosed with influenza B-associated encephalopathy. Her neurologic signs had completely recovered by day 6, and the splenial abnormalities disappeared on day 11. A review of the literature identified four additional pediatric cases of this type of influenza-associated encephalopathy: three and one were caused by influenza A and B viruses, respectively. Common features include prompt and complete recovery from clinical and radiologic abnormalities, a relatively older age (> or = 5 years), and a higher incidence among the Japanese. To better understand the pathophysiology of this encephalopathy, we examined interleukin-6, tumor necrosis factor-alpha, and soluble tumor necrosis factor receptor 1 levels in serum and cerebrospinal fluid from this patient. The results did not reveal any elevations of these cytokines in the sera or cerebrospinal fluid, suggesting that this condition is not mediated by augmented cytokine responses.

Interleukin-6 alters the cellular responsiveness to clopidogrel, irinotecan, and oseltamivir by suppressing the expression of carboxylesterases HCE1 and HCE2

Carboxylesterases constitute a class of enzymes that play important roles in the hydrolytic metabolism of drugs and other xenobiotics. Patients with liver conditions such as cirrhosis show increased secretion of proinflammatory cytokines [e.g., interleukin-6 (IL-6)] and decreased capacity of hydrolysis. In this study, we provide a molecular explanation linking cytokine secretion directly to the decreased capacity of hydrolytic biotransformation. In both primary hepatocytes and HepG2 cells, treatment with IL-6 decreased the expression of human carboxyl-esterases HCE1 and HCE2 by as much as 60%. The decreased expression occurred at both mRNA and protein levels, and it was confirmed by enzymatic assay. In cotransfection experiments, both HCE1 and HCE2 promoters were significantly repressed, and the repression was comparable with the decrease in HCE1 and HCE2 mRNA, suggesting that transrepression is responsible for the suppressed expression. In addition, pretreatment with IL-6 altered the cellular responsiveness in an opposite manner of overexpression of HCE1 and HCE2 toward various ester therapeutic agents (e.g., clopidogrel). Transfection of HCE1, for example, decreased the cytotoxicity induced by antithrombogenic agent clopidogrel, whereas pretreatment with IL-6 increased the cytotoxicity. Such a reversal was observed with other ester drugs, including anticancer agent irinotecan and anti-influenza agent oseltamivir. The altered cellular responsiveness was observed when drugs were assayed at sub- and low-micromolar concentrations, suggesting that suppressed expression of carboxylesterases by IL-6 has profound pharmacological consequences, particularly with those that are hydrolyzed in an isoform-specific manner.

The characterization of cerebrospinal fluid and serum cytokines in patients with Kawasaki disease

BACKGROUND

The central nervous system (CNS) inflammation of Kawasaki disease (KD) has not been sufficiently evaluated in spite of the complications of irritability and CSF pleocytosis.

PATIENTS AND METHODS

Cerebrospinal fluid (CSF) and serum inflammatory cytokine values were simultaneously examined in 10 patients (2.6 +/- 2.1 year of age) during the acute phase. They were all irritable and demonstrated mild consciousness disturbance.

RESULTS

The CSF IL6 was elevated (>3.0 pg/mL) in 6 patients, and 4 of them showed higher CSF than serum values. The CSF sTNFR1 was elevated (>0.5 microg/mL) in 6 patients, and 1 showed higher CSF than serum values. These CSF cytokine (IL6; 81.4 +/- 192.8 pg/mL, sTNFR1; 1.1 +/- 0.8 microg/mL) and CSF/serum ratio (IL6; 2.8 +/- 5.2, sTNFR1 0.4 +/- 0.4) in patients with KD were the same as those of patients with acute encephalitis/acute encephalopathy.

CONCLUSIONS

The differences in the inflammatory cytokine value between CSF and serum suggest that the degree of systemic vasculitis is different between CSF and the circulating blood, and some patients with KD showed a higher degree of CSF inflammation.

Serum levels of cytokines and EEG findings in children with influenza associated with mild neurological complications

We studied the relation among serum cytokine levels, EEG changes, and mild neurological complications (delirium and febrile seizure) in children with influenza. The serum levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and soluble tumor necrosis factor receptor-1 (sTNFR-1) were measured in 27 children with proven influenza infection with mild neurological complications (10 patients with delirium and 17 with febrile seizures) and seven control children. EEG was recorded in 14 children with neurological complications. EEG showed focal slowing in four of nine patients with delirium and in four of five with febrile seizures. Generalized slowing was observed in one patient with delirium. The median serum IL-6 level was 31.2+/-15.1 pg/ml (range, 7.5-64.5 pg/ml) in the delirium group, 42.3+/-44.0 pg/ml (range, 8.0-196.0 pg/ml) in the febrile seizure group, and 15.4+/-7.0 pg/ml (range, 7.2-28.0 pg/ml) in the control group. Serum TNF-alpha and sTNFR-1 levels were not different among three groups. Mild neurological complications associated with influenza were related to the mildly abnormal serum IL-6 levels and EEG findings. The combination of these parameters will be useful for early diagnosis and differentiation of neurological complications in children with influenza. Further studies will be necessary for investigating that IL-6 has the diagnostic value for differentiation between severe encephalopathy and mild neurological complications in children with influenza.

Elevated CSF IL-6 in a patient with respiratory syncytial virus encephalopathy

The patient was an 11-month-old boy who developed encephalopathy associated with respiratory syncytial virus bronchiolitis. Right hemispheric encephalopathy was indicated by left hemiparesis and a diffuse right hemispheric lesion detected with magnetic resonance imaging. Elevated levels of interleukin-6 in the cerebrospinal fluid during the acute phase suggested the involvement of increased production of one or more cytokines in the pathogenesis of viral related encephalopathy, similarly to that proposed for influenza encephalopathy.

Febrile seizures associated with influenza A

To clarify the clinical impact of influenza A on the development of febrile seizures (FS), consecutive FS patients brought to our hospital between October 2003 and September 2004 were prospectively surveyed. Patients infected with influenza A (influenza A patients) and those uninfected with influenza (non-influenza patients) were compared with regard to clinical characteristics of FS. Influenza infection was determined by rapid antigen test and/or serologically. Associations of influenza A with atypical findings of FS, including partial seizures, prolonged seizures, multiple seizures during the same illness, and 30-min or longer prolonged postictal impairment of consciousness (PPIC), were analyzed by multiple logistic regression. A total of 215 patients (47 influenza A and 168 non-influenza patients) were enrolled in the study. Age was significantly higher in the influenza A group (39.85+/-22.16 months vs. 27.51+/-17.14 months, P<0.001). Of 42 patients aged 48 months or older, which corresponded to the 80th percentile for age, 15 (35.7%) were influenza A patients, with a significantly higher incidence of such patients than in the subgroup of patients aged 47 months or younger (32/173, 18.5%) (P=0.015). On multiple logistic regression analysis, influenza A was independently associated with PPIC (odds ratio: 4.44, 95% confidence interval: 1.52-12.95, P=0.006), but not with other atypical findings. The positive association of influenza A with PPIC suggests that influenza may affect state of consciousness at the same time that it induces seizures with fever.

Analysis of gene-expression profiles by oligonucleotide microarray in children with influenza

In order to clarify the mechanism of the host response to influenza virus, gene-expression profiles of peripheral blood obtained from paediatric patients with influenza were investigated by oligonucleotide microarray. In the acute phase of influenza, 200 genes were upregulated and 20 genes were downregulated compared with their expression in the convalescent phase. Interferon-regulated genes, such as interferon-induced protein with tetratricopeptide repeats 2 (IFIT2) and vipirin, were strongly upregulated in the acute phase. Gene ontology analysis showed that immune response genes were highly overrepresented among the upregulated genes. Gene-expression profiles of influenza patients with and without febrile convulsion were also studied. In patients with febrile convulsion, 22 genes were upregulated and five were downregulated compared with their expression in patients without febrile convulsion. These results should help to clarify the pathogenesis of influenza and its neurological complications.

Prognostic predictive values of serum cytochrome c, cytokines, and other laboratory measurements in acute encephalopathy with multiple organ failure

AIMS

To evaluate the prognostic predictive values of cytochrome c, cytokines, and other laboratory measurements in serum collected during neurological onset in acute encephalopathy with multiple organ failure.

METHODS

In addition to general laboratory examinations, the concentrations of cytochrome c (apoptosis marker) and cytokines (inflammatory markers) were measured in serum samples collected at the initial phase in 29 patients with acute encephalopathy. The obtained values were evaluated as predictors for the development of severe encephalopathy.

RESULTS

Cytochrome c, tumour necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), soluble TNF-receptor 1 (sTNF-R1), and aspartate aminotransferase (AST) concentrations at the initial phase were high and correlated well with patient outcome. High concentrations of serum cytochrome c (>45 ng/ml), sTNF-R1 (>2000 pg/ml), AST (>58 IU/dl), IL-6 (>60 pg/ml), and TNF-alpha (>15 pg/ml) predicted an unfavourable prognosis (sequelae and death) at 93%, 79%, 82%, 77%, and 60%, respectively. The specificity of those markers was 100%, 89%, 83%, 100%, and 100%, respectively.

CONCLUSIONS

Serum cytochrome c is the most sensitive and specific predictor for the development of severe encephalopathy at the initial phase. Results suggest that this marker might be used to guide decisions regarding the start of the initial treatment and further intensive care.

Antipyretics and delirious behavior during febrile illness

BACKGROUND

The purpose of the present paper was to study the use of antipyretics in children with delirium associated with fever in order to clarify their possible adverse effects.

METHODS

The use of antipyretics was investigated in 26 children with delirious behavior associated with fever. Temporal relation between delirious behavior and the use of antipyretics was recognized in six children.

RESULTS

In four children, delirious behavior was observed soon after administration of antipyretics. The antipyretics used were acetaminophen in two children, mephenamate in one, and diclofenac in one. In the other two children, delirious behavior was observed when body temperature began to fall 1-2 h after administration of antipyretics. The antipyretics used were acetaminophen in one child and mephenamate in one.

CONCLUSION

A temporal relationship between antipyretics and delirious behavior was observed in some patients with febrile delirium. This suggests that antipyretics can be a trigger of delirium.

Diagnostic and predictive value of CSF d-ROM level in influenza virus-associated encephalopathy

The aim of this study was to assess the validity of serum and CSF oxidative status of patients with IE in their initial stage through the d-ROM (Diacron-Reactive Oxygen Metabolites, Italy) test, compared to those with other neurological diseases. The study was conducted on the following four groups: (1) influenza virus-associated encephalopathy (IE, n = 8), including four patients showing neurological sequelae or mortal; (2) influenza virus-associated febrile seizures (IFS, n = 11); (3) febrile convulsion (FC, n = 10): (4) enterovirus-associated encephalopathy (EE, n = 4), including one patient with neurological sequelae. The CSF d-ROM levels in the IE group were significantly higher than those in the IFS and the FC groups but not in the EE group. In addition, general laboratory findings such as leukocytes, platelets, C-reactive protein, aspartate aminotransferase, creatinine, creatinine kinase and LDH, including interleukin-6 (IL-6), were analyzed in each group. The CSF d-ROM levels in the IE group were significantly higher than those in the IFS and FC groups but not in the EE group. As for the serum d-ROM levels and general laboratory findings, with the exception of CSF IL-6 levels in IE, no significant differences were detected compared with the other groups. In patients with IE, the CSF d-ROM levels could be a valid predictive biomarker of the severity, and oxidative stress may be related to the pathogenesis of IE.

TNF-alpha and IL-6 in the diagnosis of bacterial and aseptic meningitis in children

The objective of this study was to analyze the usefulness of tumor necrosis factor-alpha and interleukin-6 cerebrospinal fluid concentrations for the differential diagnosis between bacterial and aseptic meningitis in children and in the prognostic evaluation. A cross-sectional study was performed on 35 children between 1 month and 12 years of age with suspected meningitis. Cytokines determination was performed by enzyme-linked immunosorbent assay technique. The Mann-Whitney test and Spearman's correlation coefficients were used for statistical analysis. Six children presented bacterial meningitis, 13 aseptic, and 16 had no meningitis. The tumor necrosis factor-alpha concentrations were significantly higher in the bacterial meningitis group as compared with the aseptic group (P = 0.001) and among groups with and without meningitis (P = 0.000). There was correlation between tumor necrosis factor-alpha and cerebrospinal fluid leukocytes (P = 0.019), protein (P = 0.000), and glucose (P = 0.038). There was no association between cytokines and complications of the meningitis. The tumor necrosis factor-alpha concentrations in the cerebrospinal fluid were useful markers for distinguishing bacterial from aseptic meningitis and were demonstrated to be useful in evaluating the intensity of the inflammatory process in the central nervous system.

Cerebrospinal fluid interleukin-6 levels in patients with West syndrome

Elevated cytokine response has been reported in patients with epileptic seizures. The objective of this study was to investigate the possible role of interleukin-6 (IL-6) in the pathogenesis of infantile spasms in West syndrome (WS). We measured IL-6 levels in cerebrospinal fluid (CSF) obtained from the newly diagnosed patients with WS. Twelve patients with WS (Group I) were classified as symptomatic WS (Group IA) in eight and as cryptogenic WS (Group IB) in four. The results were compared with control groups including patients with tonic-clonic seizures associated with two different kind of inflammation of central nervous system; Group IIA (infection): bacterial meningitis/encephalitis and Group IIB (trauma): post-traumatic seizures. There was no statistically significant difference between the mean values of CSF IL-6 levels in patients with WS (2.95 +/- 2.31 pg/ml) and those of subgroups of WS (Group IA: 2.26 +/- 2.01 pg/ml and Group IB: 4.33 +/- 2.52 pg/ml). Both control groups had highly increased IL-6 levels in CSF (Group IIA: 193.05 +/- 185.52 pg/ml and Group IIB: 112.74 +/- 167.44 pg/ml) than those of the patients with WS. Elevated IL-6 response in patients with tonic-clonic seizures associated with inflammation of central nervous system might be due to the seizures themselves or related to the underling etiology (infection or trauma). However, no elevated IL-6 response was found in patients with infantile spasms.

Cytokine levels in Chandipura virus associated encephalopathy in children

An association of Chandipura (CHP) virus with an explosive outbreak of encephalitis in children from India affecting 349 children with 55% mortality was recently reported. To understand the role of cytokines in the pathogenesis of CHP infection, 14 paediatric encephalitis cases admitted to a tertiary care hospital and 5 age-matched apparently healthy control children were studied. At the time of sampling, post onset of disease was < or =2 d (Group A, n = 4) and >2 d (Group B, n = 10). Concentrations of IL-2, IFN-gamma, TNF-alpha and IL-6 in mitogen stimulated PBMC supernatants of patients and controls were assessed by ELISA. IL-2 levels in Group A and B were significantly higher compared with controls (28.4+/-21.9 vs <7.8, p=0.01, 269.4+/-311.0.vs <7.8, p = 0.01). IFN-gamma levels were significantly elevated in both the groups compared with controls (394.4+/-107.7 vs 13.9+/-20.9, p = 0.01, 339.5+/-244.9 vs 13.9+/-20.9, p = 0.01). TNF-alpha and IL-6 levels were significantly higher in Group B compared with controls (573.1+/-472.5 vs 113.4.+/-148.3, p = 0.01, 486.2+/-145.7 vs 113.8+/-82.4, p = 0.003). Cytokine levels were not significantly different in Groups A and B.

Analysis of serum soluble CD40 ligand in patients with influenza virus-associated encephalopathy

CD40 ligand (CD40L) is mainly expressed on activated platelets and CD4+T cells, and it can be cleaved from the cell surface, releasing a soluble CD40L (sCD40L). Most sCD40L is derived from activated platelets. A previous paper revealed that the platelet number of patients with influenza virus-associated encephalopathy (IE) was correlated with the outcome. We determined the utility of sCD40L as a predictor for the prognosis of IE. We measured the serum concentration of sCD40L and the platelet number on the day of hospitalization in 34 patients with IE, 16 with influenza virus-associated febrile seizures (IFS), 19 with influenza virus infection without complications (Flu), and 7 with Epstein-Barr virus (EBV) infection. The serum sCD40L concentrations in IE and IFS were significantly lower than those in controls, Flu, and EBV infections. Serum sCD40L concentrations in the IE group were 0.70+/-0.43 ng/ml for deceased patients, 1.73+/-1.36 ng/ml for those with sequelae, and 3.85+/-2.91 ng/ml for those without sequelae. There was no significant difference in platelet number between IE patients with and without sequelae, while the platelet number of deceased patients with IE was significantly lower than in controls, Flu, and IFS. Serum sCD40L concentration on the day of hospitalization was more correlated with the outcome of IE than platelet number. Our findings suggest that the serum sCD40L concentration during acute IE is important for predicting the prognosis at an early stage.

Cytochrome c and tumor necrosis factor-alpha values in serum and cerebrospinal fluid of patients with influenza-associated encephalopathy

Cytochrome c and tumor necrosis factor-alpha concentrations were measured in serum and cerebrospinal fluid samples from 10 patients with influenza-associated encephalopathy. In the acute exacerbation phase, serum tumor necrosis factor-alpha and cytochrome c values were high in patients with a poor prognosis. In the convalescent phase, cerebrospinal fluid cytochrome c values increased remarkably in patients with subsequent brain atrophy.

Apoptosis under hypercytokinemia is a possible pathogenesis in influenza-associated encephalopathy

BACKGROUND

Influenza-associated encephalopathy is reported to be frequent in Japan and East Asia. No evaluating markers except interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha and no likely pathological mechanism for the disease have yet been elucidated.

METHODS

In this study, influenza-associated encephalopathy was defined by clinical symptoms, and the use of an anti-influenza antibody test and/or influenza antigen detection kits, as well as computed tomography and/or magnetic resonance imaging. The levels of proinflammatory cytokines, acute phase proteins, endothelial markers and cytochrome c were compared in sera from 11 patients with and 42 without encephalopathy.

RESULTS

Cytochrome c concentration in sera from patients with encephalopathy was markedly increased compared with that from patients without encephalopathy and normal controls. Although levels of several other proinflammatory cytokines and acute phase proteins such as TNF-alpha and IL-8 were also elevated in patients with influenza virus infection, the difference between those with and without encephalopathy, though significant, was less dramatic. The mean serum concentration of cytochrome c in 11 patients with encephalopathy, consisting of four deceased, four with and three without residual central nervous system sequelae, was 26.7 +/- 19.5 ng/mL on admission. In contrast, cytochrome c levels in 42 patients without encephalopathy were 0.3 +/- 0.7 ng/mL.

CONCLUSION

The present results indicate that cytochrome c is a useful marker to follow patients with influenza-associated encephalopathy and suggest that an apoptosis of cells in several organs including the cerebrum and liver under the influence of hypercytokinemia is a possible mechanism of the disease.

Analysis of cytokine levels and NF-kappaB activation in peripheral blood mononuclear cells in influenza virus-associated encephalopathy

BACKGROUND

Influenza virus-associated encephalopathy (IE) is suggested to be a proinflammatory cytokine-related disease.

METHODS

We measured the concentrations of interleukin-6 (IL-6), TNF-alpha, soluble TNF receptor 1 (sTNFR1), IL-10, interferon-gamma, IL-2, IL-4, and soluble E-selectin (sE-selectin) in serum and CSF during the acute stage in 30 children with IE, 20 with influenza virus-associated febrile seizures (IFS), and 39 with influenza virus infection without complications (Flu). Moreover, the activation of transcription factor NF-kappaB in peripheral blood mononuclear cells (PBMC) of 5 children with IE was examined.

RESULTS

The serum IL-6, sTNFR1, and IL-10 levels in the IE group with a poor prognosis (Group A) were significantly higher than those in the IE group without sequelae in IE (Group B), IFS, and Flu. In particular, the serum levels of IL-6, sTNFR1, and IL-10 in 5 deceased patients were markedly higher. The CSF IL-6 levels in Group A were significantly higher than those in Group B and IFS. Flow cytometric analysis revealed that NF-kappaB activation in PBMC in Group A was higher than that in Group B, IFS, and Flu.

CONCLUSION

We suggest that cytokines are produced by PBMC in IE, and that the levels of serum IL-6, sTNFR1, and IL-10, CSF IL-6, and NF-kappaB activation in PBMC are useful indicators of the severity of the disease.

Wild-type and attenuated influenza virus infection of the neonatal rat brain

Although influenza virus infection of humans has been associated with a wide spectrum of clinical neurological syndromes, the pathogenesis of influenza virus associated central nervous system (CNS) disease in humans remains controversial. To better study influenza virus neuropathogenesis, an animal model of influenza-associated CNS disease using human virus isolates without adaptation to an animal host was developed. This neonatal rat model of influenza virus CNS infection was developed using low-passage human isolates and shows outcomes in specific brain regions, cell types infected, and neuropathological outcomes that parallel the available literature on cases of human CNS infection. The degree of virus replication and spread in the rat brain correlated with the strains' neurotoxicity potential for humans. In addition, using sensitive neurobehavioral test paradigms, changes in brain function were found to be associated with areas of virus replication in neurons. These data suggest that further evaluation of this pathogenesis model may provide important information regarding influenza virus neuropathogenesis, and that this model may have possible utility as a preclinical assay for evaluating the neurological safety of new live attenuated influenza virus vaccine strains.

Interleukin-6 produces neuronal loss in developing cerebellar granule neuron cultures

CNS levels of the cytokine interleukin-6 (IL-6) are elevated during CNS injury and disease, but it is unclear if IL-6 contributes to the pathologic process. Our studies show that in a well-characterized CNS developmental model system, primary cultures of rodent cerebellar granule neurons, chronic exposure to IL-6 during neuronal development can result in cell damage and death in a subpopulation of developing granule neurons. Chronic exposure to IL-6 also increased the susceptibility of the granule neurons to a toxic insult produced by excessive activation of NMDA receptors. These results are consistent with a role for IL-6 in the neuropathology observed in the developing CNS during injury and disease.