Influenza-Associated Encephalopathy and Acute Necrotizing Encephalopathy in Children: A Retrospective Single-Center Study.

BACKGROUND Although influenza primarily affects the respiratory system, it can cause severe neurological complications, especially in younger children, but knowledge about the early indicators of acute necrotizing encephalopathy (ANE) is limited. The main purpose of this article is to summarize the clinical characteristics, diagnosis, and treatment of neurological complications of influenza in children, and to identify factors associated with ANE. MATERIAL AND METHODS This was a retrospective study of children with confirmed influenza with neurological complications treated between 01/2014 and 12/2019 at Guangzhou Women and Children's Medical Center. A receiver operating characteristics curve analysis was performed to determine the prognostic value of selected variables. RESULTS Sixty-three children with IAE (n=33) and ANE (n=30) were included. Compared with the IAE group, the ANE group showed higher proportions of fever and acute disturbance of consciousness, higher alanine aminotransferase, higher aspartate aminotransferase, higher creatinine kinase, higher procalcitonin, higher cerebrospinal fluid (CSF) protein, and lower CSF white blood cells (all P<0.05). The areas under the curve (AUCs) for procalcitonin and CSF proteins, used to differentiate IAE and ANE, were 0.790 and 0.736, respectively. The sensitivity and specificity of PCT >4.25 ng/ml to predict ANE were 73.3% and 100.0%, respectively. The sensitivity and specificity of CSF protein >0.48 g/L to predict ANE were 76.7% and 69.7%, respectively. Thirteen (43.3%) children with ANE and none with IAE died (P<0.0001). CONCLUSIONS High levels of CSF protein and serum procalcitonin might be used as early indicators for ANE. All children admitted with neurological findings, especially during the influenza season, should be evaluated for influenza-related neurological complications.

Influenza B-related meningoencephalitis in adults.

We present a case involving an 85-year-old man with acute confusion and new onset seizure following a 1-week history of respiratory prodrome. This case report describes a case of influenza B-related meningoencephalitis supported by evidence of an influenza B infection and temporal relation of the neurological event and respiratory illness in the absence of other identifiable cause. Diagnosis is guided by cerebrospinal fluid profile and nasopharyngeal PCR. Treatment is largely supportive and the effect of vaccination on prevention of this neurological complication remains unclear.

Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) levels in the cerebrospinal fluid of children with influenza-associated encephalopathy.

INTRODUCTION: To search for an index of neurologic prognosis of children with influenza-associated encephalopathy (IAE), involvement of angiogenesis-related growth factors in the pathology was investigated. PATIENTS AND METHODS: The subjects were 11 IAE patients, 6 patients with bacterial meningitis (BM), and 24 patients with non-central nervous system infection as a control group admitted to our hospital. The correlation between the vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) levels in cerebrospinal fluid and the relationship with an index of inflammatory marker, interleukin (IL)-6, were investigated. Using the Pediatric Cerebral Performance Categories (PCPC) score as a prognostic indicator, we evaluated the association between the biomarkers and neurologic prognosis. RESULT: PDGF significantly increased in the IAE group compared with that in the BM group. Cerebrospinal fluid VEGF and PDGF increased in all IAE and BM patients compared with that in the control group, and VEGF and PDGF were positively correlated in the 2 groups. No correlation was found between the cerebrospinal fluid VEGF and PDGF levels and IL-6 level in the IAE group, whereas a correlation was found in the BM group. All these factors increased in patients with poor neurologic prognosis. DISCUSSION: It is possible that the disease state of IAE can be evaluated based on vascular endothelial disorder-related markers.

14-3-3 proteins, particularly of the epsilon isoform, are detectable in cerebrospinal fluids of cerebellar diseases in children.

BACKGROUND: Detection of 14-3-3 proteins in cerebrospinal fluid (CSF) is a powerful tool for elucidating the mechanisms of neurological disorders. There have been useful studies on 14-3-3 CSF protein detection in Creutzfeldt-Jakob disease and other neurological disorders, but none on cerebellar diseases. OBJECTIVE: To elucidate whether 14-3-3 CSF proteins are a sensitive biomarker of cerebellar disruption in children. MATERIALS AND METHODS: We examined 14-3-3 CSF proteins by immunoblotting in seven patients with cerebellar disorders: two with acute cerebellitis, two with acute cerebellar ataxia, and three with cerebellar atrophy. We also investigated 14-3-3 CSF proteins in four cases of febrile seizure and three of influenza-related encephalopathy. Isoforms of 14-3-3 proteins were also identified using isoform-specific antibodies. RESULTS: 14-3-3 proteins were detected in CSF of six patients with cerebellar disorders, the exception being one with acute cerebellar ataxia caused by viral infection. Interestingly, only the 14-3-3 ε isoform was detected in two tested patients with cerebellar involvement. Moreover, longitudinal analysis of 14-3-3 CSF proteins in one patient with infantile neuroaxonal dystrophy showed that the 14-3-3 band density proportionally decreased when the cerebellar atrophy gradually progressed. Another CSF derived from a case of febrile seizure showed no 14-3-3 proteins, whereas all those derived from influenza-related encephalopathy demonstrated 14-3-3 CSF proteins with six isoforms. CONCLUSIONS: This is the first report on 14-3-3 CSF proteins as a significant biomarker of cerebellar disruption, as well as other brain diseases. Since 14-3-3 ε is localized in the molecular layer of cerebellum, the unique detection of 14-3-3 ε may indicate cerebellar involvement in the brain.

Influenza B-associated encephalopathy in two adults.

Influenza virus is associated with a variety of neurological complications, of which the most commonly encountered are seizures and encephalopathy. Acute encephalitis and postinfectious encephalopathy have been reported infrequently in association with influenza A and B virus infections. We describe two previously healthy adults who presented with encephalopathy with a virologically documented influenza B infection.

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.

Influenza-associated encephalopathy with elevated antibody titers to pandemic (H1N1) 2009 influenza.

Pandemic H1N1 influenza (pH1N1) has been associated with encephalopathy, but the role of adaptive immunity in disease pathogenesis remains unclear. A child presented with seizures 5 days after onset of respiratory symptoms with pH1N1, with no detectable virus in cerebrospinal fluid. The authors compared her serum cytokines and pH1N1 antibody titers to those of 22 children with pH1N1, seasonal influenza, or other respiratory viral infections. They also compared her cerebrospinal fluid biomarkers to those of 20 children with confirmed or probable central nervous system infection or viral infection without central nervous system involvement. Her serum antibody titers were several-fold higher, and levels of proinflammatory cytokines in cerebrospinal fluid and serum were lower than those of controls. Antibody titers in cerebrospinal fluid were undetectable. The delayed onset of neurologic manifestations, normal cytokine levels in serum and cerebrospinal fluid, markedly elevated hemagglutinating and neutralizing antibody titers, and absence of virus and antibodies in cerebrospinal fluid raise the possibility of a post-infectious autoimmune-mediated process.

Neurological complications of pandemic influenza A H1N1 2009 infection: European case series and review.

Neurological manifestations and outcomes of children with the 2009 H1N1 virus infection have been reported in three American series and from smaller cohorts and case reports worldwide. Of the 83 children admitted between April 2009 and March 2010 with H1N1 virus infection to a tertiary children's hospital in a European setting, five children aged between 2 and 10 years had neurological symptoms. Four patients had seizures and encephalopathy at presentation. One patient presented with ataxia; one developed neuropsychiatric manifestations, and two developed movement disorders during the disease course. Early neuroimaging showed evidence of acute necrotising encephalopathy (ANE) in one case and non-specific white matter changes in another. Initial neuroimaging was normal for the other three, but interval MRI showed increased signal in bilateral periventricular distribution in one and significant cerebral volume loss in the other. Clinical outcomes varied: two recovered fully while three had residual seizures and/or significant cognitive deficits. Conclusion An analysis of our patients along with all reported cases reveal that seizures and encephalopathy were common neurological presentations associated with pandemic 2009 H1N1 influenza virus infection in children requiring hospital admission. Neuroimaging suggestive of ANE, basal ganglia involvement and volume loss appears to be associated with worse neurological outcome.

Novel influenza A (H1N1) encephalitis in a 3-month-old infant.

Seasonal influenza virus infection has been associated with a variety of neurologic complications. We report a case of novel influenza A (H1N1) encephalitis in an infant aged 3 months with an upper respiratory infection, who presented seizures. The infection was confirmed in nasopharyngeal aspirate and cerebrospinal fluid. Treatment with oseltamivir was started. He was discharged without any neurologic sequelae.

Lethal influenza B myocarditis in a child and review of the literature for pediatric age groups.

CASE PRESENTATION: We report on the case of a 5 year-old girl who developed fulminant myocarditis due to acute infection with influenza virus type B. Cardiac arrest occurred suddenly, resuscitation efforts were not successful, and the patient died of congestive heart failure 24 h after admission to the hospital. DIAGNOSIS: Lymphocytic infiltration of cardiac tissues and virologic studies confirmed the suspected diagnosis of acute viral myocarditis. CONCLUSION: In conclusion, influenza virus type B is one of the infective agents that can cause rapid and fatal myocarditis in previously healthy children. Early cardiac support may be the only option to prevent fatal outcome.

14-3-3 protein detection in the cerebrospinal fluid of patients with influenza-associated encephalopathy.

Influenza-associated encephalopathy is characterized by high fever, convulsions, and loss of consciousness associated with influenza infection in children, but its pathophysiology remains to be clarified. We examined 14-3-3 proteins, which are acidic brain proteins, in cerebrospinal fluid by immunoblotting in four patients with influenza-associated encephalopathy, four patients with influenza without encephalopathy, and four patients with another encephalopathy. Interestingly, we detected 14-3-3 proteins in all four patients with influenza-associated encephalopathy (100%) but not in any of the other patients. 14-3-3 isoforms, including beta, gamma, epsilon, xi, and theta, were found in the cerebrospinal fluid of the patients with influenza-associated encephalopathy, suggesting extensive damage to the brain. We conclude that 14-3-3 proteins in cerebrospinal fluid are highly detectable in influenza-associated encephalopathy and thus can be used as a rapid diagnostic marker.

Primary biomarkers in cerebral spinal fluid obtained from patients with influenza-associated encephalopathy analyzed by metabolomics.

In order to search for the specific biomarkers of patients with influenza-associated encephalopathy this article analyzed all metabolites in cerebrospinal fluid (CSF) by using metabolome analysis. In all metabolites, the peaks of two molecular weights, 246.0092 and 204.0611, were significantly higher than those in other diseases including influenza without convulsion (p < .05). The peak of a molecular weight 228.0247 in all of the patients except one was less than that in other patients. These results indicate that the new metabolites detected in CSF would be primary markers for the diagnosis of influenza-associated encephalopathy.

Nitrite/nitrate (NOx) and zinc concentrations in influenza-associated encephalopathy in children with different sequela.

NOx (NO2 and NO3) in CSF obtained from 22 patients with influenza-associated encephalopathy were higher than those of a control group. Within the different prognosis, there were no significant differences in NOx levels. By analyzing the serum obtained from patients infected with influenza, including encephalopathy, with others, the serum zinc levels did show marked differences between them. Four out of eleven patients with influenza-associated encephalopathy showed low zinc levels below the normal range. However, there were no significant differences in the zinc levels between the group with sequela and without sequela. These results indicate that the increase of NOx levels detected in influenza-associated encephalopathy relates to the low zinc levels, and both low molecules might play an important role for the cause of encephalopathy.

Extraordinary changes in excitatory amino acid levels in cerebrospinal fluid of influenza-associated encephalopathy of children.

The correlation between the glutamate-glutamine cycle and nitric oxide (NO) production in the central nervous system (CNS) of a new type of influenza-associated encephalopathy in children is discussed. When measurements of several amino acids and NOx (nitrite/nitrate) levels in the cerebrospinal fluid (CSF) using HPLC-fluorescence and -UV methods, respectively, were made. the CSF glutamate levels of patients with the new type of encephalitis were significantly lower, and both glutamine and NOx levels were significantly higher than those of the control group and the patients of the meningitis group. Results indicate that the turnover rate of glutamate in CNS, particularly in the brain, increases in the influenza-associated encephalopathy. The high mortality in the disease may correlate with the hyperactivity of supra-spinal glutamate neurons and the subsequent high activity levels of NOx in CNS.

NOx (nitrite/nitrate) in cerebral spinal fluids obtained from patients with influenza-associated encephalopathy.

It has become evident that the number of patients with a new type of influenza-associated encephalopathy is increasing in Japan. Nitric oxide (NO), a simple free radical gas, elicits a wide range of physiological and pathophysiological effects. We measured the nitrite/nitrate (NO x ) levels in cerebral spinal fluid obtained from patients with influenza-associated encephalopathy in order to evaluate the correlation between the NO production and the process of influenza-associated encephalopathy. Fifteen children were enrolled, aged from 1 to 9 years. As control we used 14 cerebral spinal fluids obtained from patients with urinary tract infection, respiratory infection or mumps meningitis without any sequela. NO 3 in influenza-associated encephalopathy was significantly higher than that of control group. On the other hand NO 2 was not significantly higher than that of control group. In particular, 4 out of 5 fatal cases revealed high NO 2 or NO 3. One case having normal levels in NO 2 and NO 3 showed that NH 3 was high. These results revealed that NO plays a role in influenza-associated encephalopathy through indirect effects of NO.

Headache with temporary neurological symptoms and lymphocytic pleocytosis: a case report and etiologic hypothesis.

A 30-year-old man without previous attacks of migraine, despite a family history of migraine, presented with moderate headache and temporary focal neurological signs and symptoms. The patient had had, two weeks previously, a prodromic flu-like illness. Cerebrospinal fluid (CSF) analysis showed lymphocytic pleocytosis and increased total protein. Extensive microbiological determinations were negative. Routine hematological, immunological, blood and urine tests were normal. Electroencephalography showed a focal slowing in the right temporal area. Brain SPECT, performed during a symptom-free period, revealed decreased tracer uptake in the left temporal and insula cortices,topographicallyconsistent with abnormalities on brainstem auditory evoked potentials. Computed tomography and magnetic resonance imaging of the brain were normal. A cardiovascular examination provided normal results. The patient completely recovered within 2 days. This condition is suggestive of "headache with neurologic deficits and CSF lymphocytosis" (HaNDL syndrome). I hypothesize that this syndrome could be produced by the direct action of a virus.