Neurologic complications and outcomes of pandemic (H1N1) 2009 in Korean children

A Favorable Treatment Outcome in RANBP2 and Influenza Associated Acute Necrotizing Encephalitis

In current literature, there is uncertainty in the pathophysiology and management of influenza-associated Acute Necrotizing Encephalitis. Because of this and the rarity of the disease, no clear treatment guidelines exist. It is thought that treatment after 24 h of symptom onset or known brainstem involvement are poor predictors of outcome. Here, we present a case that provides support for aggressive management of the inflammatory cascade with combination high-dose steroid, immunoglobulin, and anti-viral therapy with oseltamivir despite initiation after 24 h from symptom onset, brainstem involvement, and a pathogenic RANBP2 gene mutation which mechanistically increases oxidative stress, cytokine effects, and possibly viral invasion into brain tissue and vasculature.

Influenza-associated Neurologic Complications in Hospitalized Pediatric Patients: A Multicenter Retrospective Study in Republic of Korea

BACKGROUND

The rates of influenza-associated neurologic complications are variable among studies, and a difference has been observed between the Western and Asian countries. The study aims to evaluate the frequency and characteristics of influenza-associated neurologic complications.

METHODS

We performed a retrospective review of hospitalized cases of influenza infection from October 2010 to April 2017 from 3 referral hospitals.

RESULTS

A total of 1988 influenza cases were identified. Influenza-associated neurologic complications were 161 cases (8.1%); influenza virus A was detected in 113 (70.2%) cases, B in 47 (29.2%) cases and both A and B in 1 case (0.6%). Twenty-four patients (15%) had underlying neurologic diseases. The most common diagnosis was a simple febrile convulsion (44%), followed by complex febrile convulsion (29%), fever-provoked seizure under pre-existing neurologic disease or afebrile seizure (14%), encephalopathy/encephalitis (8%) and meningitis (5%). Most of the patients fully recovered (96%). Three patients (1.9%) died of myocarditis (n = 1), encephalopathy (n = 1), and simultaneous encephalitis and myocarditis (n = 1). Pre-existing neurologic disease, age groups of 6 months to 6 years and 6-12 years were a risk factor of influenza-associated neurologic complications with an adjusted odds ratio of 5.41 (95% confidence interval [CI] 3.23-9.06, P < 0.001), 12.99 (95% CI 1.77-95.19, P = 0.01) and 8.54 (95% CI 1.14-64.79, P = 0.04), respectively. There was no association between neuropsychiatric adverse events and oseltamivir prescription (P = 0.17).

CONCLUSIONS

Influenza-associated neurologic complications are not uncommon, and most patients fully recovered. The frequency of influenza-associated neurologic complications in Korean children was not significantly different from that of children in Western countries.

Prognostic Factors Among Children With Acute Encephalitis/Encephalopathy Associated With Viral and Other Pathogens

BACKGROUND

Acute encephalitis/encephalopathy (AE) associated with viral and other pathogens leads to neurological sequelae and mortality. Knowing the prognostic factors is therefore important for immediate interventions. We examined early-phase unfavorable prognostic factors among children with AE using a nationwide database.

METHODS

We performed a retrospective cohort study using the Diagnosis Procedure Combination database, which includes approximately half of acute-care inpatients across Japan. We enrolled children aged ≤ 18 years who were hospitalized for AE and discharged from April 2010 to March 2018. The composite unfavorable outcome included the following at discharge: in-hospital death, tracheostomy, enteral tube feeding, and physical rehabilitation. Unfavorable prognostic factors were assessed using a multivariable Poisson regression model including patient characteristics, associated pathogens, and interventions within 2 days of admission adjusting for within-hospital clustering.

RESULTS

This study included 9386 children with AE (median age, 3 years). A total of 241 (2.6%) in-hospital deaths occurred, and 2027 (21.6%) patients had the composite unfavorable outcome. Significant unfavorable prognostic factors were age 12-18 years, congenital anomalies, epilepsy, and Japan Coma Scale score of 100-300 at admission (ie, worse levels of consciousness). In contrast, herpes simplex virus infection and influenza virus infection were associated with favorable outcomes.

CONCLUSIONS

We identified early-phase (within 2 days of admission) unfavorable prognostic factors among children with AE. These findings will help identify patients who may benefit from early aggressive therapeutic interventions.

Clinical Spectrum and Burden of Influenza-Associated Neurological Complications in Hospitalised Paediatric Patients

BACKGROUND

Influenza is one of the most common causes of acute respiratory tract infections around the world. Influenza viruses can cause seasonal epidemics. There remains limited information on the impact of both seasonal influenza A and influenza B related hospitalisations from neurological complications in paediatric populations in Asia.

OBJECTIVES

To examine both the clinical spectrum and healthcare burden of influenza-associated neurological complications (IANCs) within the paediatric population of Hong Kong.

METHODS

We conducted a population-based retrospective study to identify all paediatric patients (<18 years) admitted to a public hospital in Hong Kong with a confirmed influenza A or B infection between 2014 and 2018 using the Clinical Data Analysis and Reporting System of the Hospital Authority. The clinical spectrum of the paediatric patients with IANCs was studied. The clinical burden of paediatric influenza patients with IANCs were compared to paediatric influenza patients without neurological complications.

RESULTS

A total of 28,016 children admitted to the paediatric wards diagnosed to have influenza A or B infection were identified, accounting for 5.7% (28,016/489,955) of total paediatric admissions. 67.3% had influenza A and 32.7% had influenza B, and 8.9% had IANCs. The mean annual incidence of IANCs in children was 57 per 100,000 population. The spectrum of IANCs in our paediatric patients included febrile seizures (80.6%), myositis (11.4%), seizures with fever (5.4%), influenza-associated encephalitis/encephalopathy (IAE) (2.6%) and rarely Guillain-Barré syndrome (0.04%). Most paediatric patients with IANCs (85.5%) presented at a young age of <6 years. Paediatric patients with IANCs had significant longer hospital stays (p < 0.001), higher percentages of mechanical ventilation use (p < 0.05) and PICU admissions (p < 0.001), and higher mortality rates (p < 0.001) compared to those without neurological complications. Amongst those with IANCs, IAE was the sole cause of all seven reported mortalities.

CONCLUSIONS

Seasonal influenza A & B is a common cause of hospitalisation for paediatric patients in Hong Kong. We found neurological complications from influenza A and B caused a significantly higher clinical burden compared to those without neurological complications. Children in younger age groups (<6 years old) are at highest risk and thus increasing vaccination coverage to this age group is recommended.

Neurological associations of COVID-19

BACKGROUND

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is of a scale not seen since the 1918 influenza pandemic. Although the predominant clinical presentation is with respiratory disease, neurological manifestations are being recognised increasingly. On the basis of knowledge of other coronaviruses, especially those that caused the severe acute respiratory syndrome and Middle East respiratory syndrome epidemics, cases of CNS and peripheral nervous system disease caused by SARS-CoV-2 might be expected to be rare.

RECENT DEVELOPMENTS

A growing number of case reports and series describe a wide array of neurological manifestations in 901 patients, but many have insufficient detail, reflecting the challenge of studying such patients. Encephalopathy has been reported for 93 patients in total, including 16 (7%) of 214 hospitalised patients with COVID-19 in Wuhan, China, and 40 (69%) of 58 patients in intensive care with COVID-19 in France. Encephalitis has been described in eight patients to date, and Guillain-Barré syndrome in 19 patients. SARS-CoV-2 has been detected in the CSF of some patients. Anosmia and ageusia are common, and can occur in the absence of other clinical features. Unexpectedly, acute cerebrovascular disease is also emerging as an important complication, with cohort studies reporting stroke in 2-6% of patients hospitalised with COVID-19. So far, 96 patients with stroke have been described, who frequently had vascular events in the context of a pro-inflammatory hypercoagulable state with elevated C-reactive protein, D-dimer, and ferritin. WHERE NEXT?: Careful clinical, diagnostic, and epidemiological studies are needed to help define the manifestations and burden of neurological disease caused by SARS-CoV-2. Precise case definitions must be used to distinguish non-specific complications of severe disease (eg, hypoxic encephalopathy and critical care neuropathy) from those caused directly or indirectly by the virus, including infectious, para-infectious, and post-infectious encephalitis, hypercoagulable states leading to stroke, and acute neuropathies such as Guillain-Barré syndrome. Recognition of neurological disease associated with SARS-CoV-2 in patients whose respiratory infection is mild or asymptomatic might prove challenging, especially if the primary COVID-19 illness occurred weeks earlier. The proportion of infections leading to neurological disease will probably remain small. However, these patients might be left with severe neurological sequelae. With so many people infected, the overall number of neurological patients, and their associated health burden and social and economic costs might be large. Health-care planners and policy makers must prepare for this eventuality, while the many ongoing studies investigating neurological associations increase our knowledge base.

Characteristics and Outcomes of Influenza-Associated Encephalopathy Cases Among Children and Adults in Japan, 2010-2015

Background

Influenza-associated encephalopathy (IAE) can result in severe neurologic disease with high mortality. Most IAE cases are reported among children worldwide. Understanding of IAE among adults is limited.

Methods

Data were collected on IAE cases reported through the National Epidemiological Surveillance of Infectious Diseases database in Japan from 2010 through 2015. IAE cases were stratified by age category and analyzed using descriptive statistics to assess differences in characteristics and outcomes.

Results

Among 385 IAE cases, median age at diagnosis was 7 years (range, 0-90), and 283 (74%) were aged <18 years. Mean seasonal incidence of IAE cases among children and adults (aged ≥18 years) was 2.83 and 0.19 cases per 1000000 population, respectively. IAE incidence did not vary by predominant influenza A virus subtype. IAE frequency was highest in school-aged (5-12 years) children (38%), followed by children aged 2-4 years (21%) and adults aged 18-49 years (11%). The proportion of cases with seizures was more common in children. There were more cases with cerebrospinal fluid pleocytosis among adults than in children (P < .01), especially among those aged 18-49 (17%) and 50-64 (19%) years. Case fatality proportion was highest in those aged 40-64 (17%) and ≥65 (20%) years.

Conclusions

We found differences in the clinical features of IAE between adults and children in Japan. Although IAE incidence was higher in children, mortality was higher in adults. Efforts are needed to prevent and improve survival of patients with IAE, especially in adults.

Epilepsy in Children After Pandemic Influenza Vaccination

OBJECTIVES

To determine if pandemic influenza vaccination was associated with an increased risk of epilepsy in children.

METHODS

Information from Norwegian registries from 2006 through 2014 on all children <18 years living in Norway on October 1, 2009 was used in Cox regression models to estimate hazard ratios for incident epilepsy after vaccination. A self-controlled case series analysis was used to estimate incidence rate ratios in defined risk periods after pandemic vaccination.

RESULTS

In Norway, the main period of the influenza A subtype H1N1 pandemic was from October 2009 to December 2009. On October 1, 2009, 1 154 113 children <18 years of age were registered as residents in Norway. Of these, 572 875 (50.7%) were vaccinated against pandemic influenza. From October 2009 through 2014 there were 3628 new cases of epilepsy (incidence rate 6.09 per 10 000 person-years). The risk of epilepsy was not increased after vaccination: hazard ratio: 1.07; 95% confidence interval: 0.94-1.23. Results from the self-controlled case series analysis supported the finding of no association between vaccination and subsequent epilepsy.

CONCLUSIONS

Pandemic influenza vaccination was not associated with increased risk of epilepsy. Concerns about pandemic vaccination causing epilepsy in children seem to be unwarranted.

Neuroinfluenza: evaluation of seasonal influenza associated severe neurological complications in children (a multicenter study)

PURPOSE

Although influenza primarily affects the respiratory system, in some cases, it can cause severe neurological complications. Younger children are especially at risk. Pediatric literature is limited on the diagnosis, treatment, and prognosis of influenza-related neurological complications. The aim of the study was to evaluate children who suffered severe neurological manifestation as a result of seasonal influenza infection.

METHODS

The medical records of 14 patients from six hospitals in different regions of the country were evaluated. All of the children had a severe neurological manifestations related to laboratory-confirmed influenza infection.

RESULTS

Median age of the patients was 59 months (6 months-15.5 years) and nine (64.3%) were male. Only 4 (28.6%) of the 14 patients had a comorbid disease. Two patients were admitted to hospital with influenza-related late complications, and the remainder had acute complication. The most frequent complaints at admission were fever, altered mental status, vomiting, and seizure, respectively. Cerebrospinal fluid (CSF) analysis was performed in 11 cases, and pleocytosis was found in only two cases. Neuroradiological imaging was performed in 13 patients. The most frequent affected regions of nervous system were as follows: cerebellum, brainstem, thalamus, basal ganglions, periventricular white matter, and spinal cords. Nine (64.3%) patients suffered epileptic seizures. Two patients had focal seizure, and the rest had generalized seizures. Two patients developed status epilepticus. Most frequent diagnoses of patients were encephalopathy (n = 4), encephalitis (n = 3), and meningitis (n = 3), respectively. The rate of recovery without sequelae from was found to be 50%. At discharge, three (21.4%) patients had mild symptoms, another three (21.4%) had severe neurological sequelae. One (7.1%) patient died. The clinical findings were more severe and outcome was worse in patients <5 years old than patients >5 years old and in patients with comorbid disease than previously healthy group.

CONCLUSION

Seasonal influenza infection may cause severe neurological complications, especially in children. Healthy children are also at risk such as patients with comorbid conditions. All children who are admitted with neurological findings, especially during the influenza season, should be evaluated for influenza-related neurological complications even if their respiratory complaints are mild or nonexistent.

Successful Treatment of Influenza-Associated Acute Necrotizing Encephalitis in an Adult Using High-Dose Oseltamivir and Methylprednisolone: Case Report and Literature Review

A case of influenza-associated acute necrotizing encephalitis (ANE) is described in an otherwise healthy adult. The patient was treated successfully with a combination of high-dose methylprednisolone and high-dose oseltamivir. The patient relapsed after discontinuing 150 mg twice daily oseltamivir but quickly improved and eventually recovered after reinitiation of high-dose oseltamivir for an additional 2 weeks. The clinical presentation, pathogenesis, and treatment of influenza-associated ANE is reviewed. The use of high-dose oseltamivir in combination with methylprednisolone may offer additional therapeutic benefit for this rare and poorly understood complication of influenza infection.

Successful Treatment of Influenza-Associated Acute Necrotizing Encephalitis in an Adult Using High-Dose Oseltamivir and Methylprednisolone: Case Report and Literature Review

A case of influenza-associated acute necrotizing encephalitis (ANE) is described in an otherwise healthy adult. The patient was treated successfully with a combination of high-dose methylprednisolone and high-dose oseltamivir. The patient relapsed after discontinuing 150 mg twice daily oseltamivir but quickly improved and eventually recovered after reinitiation of high-dose oseltamivir for an additional 2 weeks. The clinical presentation, pathogenesis, and treatment of influenza-associated ANE is reviewed. The use of high-dose oseltamivir in combination with methylprednisolone may offer additional therapeutic benefit for this rare and poorly understood complication of influenza infection.

Neurological events related to influenza A (H1N1) pdm09

OBJECTIVES

To review neurological complications after the influenza A (H1N1) pdm09, highlighting the clinical differences between patients with post-vaccine or viral infection.

DESIGN

A search on Medline, Ovid, EMBASE, and PubMed databases using the keywords “neurological complications of Influenza AH1N1” or “post-vaccine Influenza AH1N1.”

SETTING

Only papers written in English, Spanish, German, French, Portuguese, and Italian published from March 2009 to December 2012 were included.

SAMPLE

We included 104 articles presenting a total of 1636 patient cases. In addition, two cases of influenza vaccine-related neurological events from our neurological care center, arising during the period of study, were also included.

MAIN OUTCOME MEASURES

Demographic data and clinical diagnosis of neurological complications and outcomes: death, neurological sequelae or recovery after influenza A (H1N1) pdm09 vaccine or infection.

RESULTS

The retrieved cases were divided into two groups: the postvaccination group, with 287 patients, and the viral infection group, with 1349 patients. Most patients in the first group were adults. The main neurological complications were Guillain-Barre syndrome (GBS) or polyneuropathy (125), and seizures (23). All patients survived. Pediatric patients were predominant in the viral infection group. In this group, 60 patients (4.7%) died and 52 (30.1%) developed permanent sequelae. A wide spectrum of neurological complications was observed.

CONCLUSIONS

Fatal cases and severe, permanent, neurological sequelae were observed in the infection group only. Clinical outcome was more favorable in the post-vaccination group. In this context, the relevance of an accurate neurological evaluation is demonstrated for all suspicious cases, as well as the need of an appropriate long-term clinical and imaging follow-up of infection and post-vaccination events related to influenza A (H1N1) pdm09, to clearly estimate the magnitude of neurological complications leading to permanent disability.

Central nervous system manifestations in pediatric patients with influenza A H1N1 infection during the 2009 pandemic

BACKGROUND

A novel H1N1 influenza A virus (A(H1N1)pdm09) particularly affected individuals <24 years of age during the 2009 pandemic. This study sought to better understand the risks and outcomes of central nervous system complications associated with pandemic influenza in the pediatric population.

METHODS

Retrospective review of patients with laboratory-confirmed influenza A(H1N1)pdm09 infection and central nervous system manifestations at Texas Children's Hospital between April 2009 and June 2010.

RESULTS

Among 365 patients with influenza A(H1N1)pdm09, 32 (8.8%) had central nervous system manifestations at a median age of 4 years. Eight (25.0%) were previously healthy, and 12 (37.5%) had neurological pre-existing conditions. Of the 32 cases of influenza with neurological complications, seizure (n = 17; 53.1%) was the most common central nervous system manifestation, followed by encephalitis (n = 4; 12.5%), meningitis (n = 4; 12.5%), encephalopathy (n = 3; 9.4%), meningismus (n = 3; 9.4%), focal hemorrhagic brain lesions (n = 2; 6.3%), brain infarction (n = 1; 3.1%), and sensorineural hearing loss (n = 1; 3.1%). Two patients demonstrated two or more types of central nervous system complications. One patient had abnormal cerebrospinal fluid with pleocytosis. Almost two thirds of the children with central nervous system manifestations required intensive care unit admission and nearly half required mechanical ventilation. There were no deaths.

CONCLUSIONS

Patients with pre-existing neurological conditions were at greater risk for central nervous system manifestations during pandemic influenza infection. Patients with central nervous system manifestations were more likely to experience severe illness, characterized by intensive care unit admission and mechanical ventilation, although overall outcomes were good. Influenza prevention in patients with underlying medical conditions, particularly those with neurological conditions, is important.

Influenza virus A(H3N2) strain isolated from cerebrospinal fluid from a patient presenting myelopathy post infectious

BACKGROUND

Neurological involvement during influenza infection has been described during epidemics and is often consistent with serious sequelae or death.

OBJECTIVE

To investigate the etiologic agent involved in myelopathy post influenza-like syndrome.

STUDY DESIGN

This investigation focuses on virus isolation from the cerebrospinal fluid (CSF) collected from a 19-year-old male student presenting with clinical diagnosis of myelopathy post influenza-like syndrome. To achieve this goal, different cell cultures and molecular methodologies were carried out.

RESULTS

Influenza virus A(H3N2) strain was isolated in MDCK cell culture; virus particles were observed under electron microscopy. Phylogenetics analyses showed that the Brazilian influenza A(H3N2) strains were closely related to the A/Perth/16/2009-like.

CONCLUSION

This study demonstrates that influenza virus A(H3N2) strain was the cause of illness of the students. According to the Brazilian influenza virus sentinel surveillance data A/Perth/16/2009-LIKE (H3N2) strain has predominated during the 2010 influenza virus season in Brasília-DF.

Recurrent plastic bronchitis in a child with 2009 influenza A (H1N1) and influenza B virus infection

Plastic bronchitis is an uncommon disorder characterized by the formation of bronchial casts. It is associated with congenital heart disease or pulmonary disease. In children with underlying conditions such as allergy or asthma, influenza can cause severe plastic bronchitis resulting in respiratory failure. A review of the literature showed nine cases of plastic bronchitis with H1N1 including this case. We report a case of a child with recurrent plastic bronchitis with eosinophilic cast associated with influenza B infection, who had recovered from plastic bronchitis associated with an influenza A (H1N1) virus infection 5 months previously. To the best of our knowledge, this is the first case of recurrent plastic bronchitis related to influenza viral infection. If patients with influenza virus infection manifest acute respiratory distress with total lung atelectasis, clinicians should consider plastic bronchitis and early bronchoscopy should be intervened. In addition, management for underlying disease may prevent from recurrence of plastic bronchitis.