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

Hybrid capture shotgun sequencing detected unexpected viruses in the cerebrospinal fluid of children with acute meningitis and encephalitis

PURPOSE

Investigation of undiagnosed cases of infectious neurological diseases, especially in the paediatric population, remains a challenge. This study aimed to enhance understanding of viruses in CSF from children with clinically diagnosed meningitis and/or encephalitis (M/ME) of unknown aetiology using shotgun sequencing enhanced by hybrid capture (HCSS).

METHODS

A single-centre prospective study was conducted at Sant Joan de Déu University Hospital, Barcelona, involving 40 M/ME episodes of unknown aetiology, recruited from May 2021 to July 2022. All participants had previously tested negative with the FilmArray Meningitis/Encephalitis Panel. HCSS was used to detect viral nucleic acid in the patients' CSF. Sequencing was performed on Illumina NovaSeq platform. Raw sequence data were analysed using CZ ID metagenomics and PikaVirus bioinformatics pipelines.

RESULTS

Forty episodes of M/ME of unknown aetiology in 39 children were analysed by HCSS. A significant viral detection in 30 CSF samples was obtained, including six parechovirus A, three enterovirus ACD, four polyomavirus 5, three HHV-7, two BKV, one HSV-1, one VZV, two CMV, one EBV, one influenza A virus, one rhinovirus, and 13 HERV-K113 detections. Of these, one sample with BKV, three with HHV-7, one with EBV, and all HERV-K113 were confirmed by specific PCR. The requirement for Intensive Care Unit admission was associated with HCSS detections.

CONCLUSION

This study highlights HCSS as a powerful tool for the investigation of undiagnosed cases of M/ME. Data generated must be carefully analysed and reasonable precautions must be taken before establishing association of clinical features with unexpected or novel virus findings.

Shotgun metagenomics to investigate unknown viral etiologies of pediatric meningoencephalitis

INTRODUCTION

Meningoencephalitis in children poses a diagnostic challenge, as etiology remains unknown for most of patients. Viral metagenomics by shotgun sequencing represents a powerful tool for investigating unknown viral infections related to these cases.

PATIENTS AND METHODS

In a two-year, reference-centre, retrospective study, we investigated the usefulness of viral metagenomics of cerebrospinal fluid (CSF) for the diagnosis of viral infectious meningoencephalitis in forty seven pediatric patients, forty of them previously tested negative with a routine neurologic panel of viral targets that included herpesvirus 1-3 and enterovirus. We enhanced the detection by targeting viral sequences by hybrid capture. Raw sequence data was analysed using three bioinformatics pipelines.

RESULTS

Out of forty remaining children with meningoencephalitis of unknown viral etiology, a significant detection of viral nucleic acid by shotgun sequencing was found in twenty one, which was confirmed in ten of them by specific PCR: seven human endogenous retrovirus K113 (HER K113), one parechovirus 3, one human herpesvirus 5 (HHV5); one enterovirus B (Echovirus 9). The remaining eleven CSF were not confirmed by PCR: three rotavirus, one human herpesvirus 7 (HHV7), one influenza A, one mastadenovirus C, one sindbis virus, one torque teno virus, one human immunodeficiency virus 1 (HIV-1), one human alphaherpesvirus 3 (HHV3), one human alphaherpesvirus 2 (HHV2).

CONCLUSIONS

Underutilization of currently available meningitis-encephalitis diagnostic techniques such as BioFire® FilmArray® is the main cause of undiagnosed cases of meningoencephalitis. However, in this study we detected uncommon viruses that should be considered, including virus, rotavirus, sindbis virus, influenza A virus and HHV7. No other viral sequences that could be readily linked to CNS inflammation were detected. Some findings may stem from reagent or sample contamination, as seen with papillomavirus; for others, the clinical relevance of the virus remains uncertain and should be substantiated by further studies, as is the case with endogenous retrovirus K113 virus. Online bioinformatics pipeline CZID represents a valuable tool for analysing shotgun sequencing data in cases of neurological conditions with unknown etiology. Altogether, this study highlights the potential of shotgun sequencing in identifying previously unknown viral neuropathogens and sheds light on the interpretation issues related to its application in clinical microbiology.

Neurological Manifestations of Influenza A (H1N1): Clinical Features, Intensive Care Needs, and Outcome

OBJECTIVES

To describe neurological manifestations in children with Influenza A (H1N1).

METHODS

This retrospective study was conducted in the Pediatric intensive care unit (PICU) and Pediatric Neurology unit of a tertiary care teaching hospital in North India involving children with PCR confirmed Influenza A (H1N1) with neurological manifestations during 2019 outbreak.

RESULTS

Six children (5 females, 1 male) were enrolled. All presented with neurological symptoms (seizures and altered sensorium) accompanied with fever and respiratory symptoms with duration of illness of 2-7 d. The admission Glasgow Coma Scale ranged from 4 to 12. Only 2 cases showed cerebrospinal fluid pleocytosis. Neuroimaging was suggestive of diffuse cerebral edema, acute necrotizing encephalopathy of childhood, and acute disseminated encephalomyelitis. All were treated with Oseltamivir. Four cases had clinical features of raised intracranial pressure (ICP) and were managed in PICU, 3 of them needed mechanical ventilation, 3 needed vasoactive drugs, 3 received 3% saline infusion, 1 underwent invasive ICP monitoring, and 3 (cases 4, 5 and 6) received intravenous methylprednisolone (30 mg/kg) for 5 d. Total duration of hospital stay was 10-30 d. Case 2 expired due to refractory raised ICP. Among survivors, 3 children had residual neurological deficits and the remaining 2 had achieved premorbid condition.

CONCLUSIONS

Influenza A (H1N1) can present with isolated or predominant neurological manifestations which can contribute to poor outcome. The authors suggest to rule out H1N1 in any child who presents with unexplained neurological manifestations during seasonal outbreaks of H1N1.

Neurologic manifestations and complications of pandemic influenza A H1N1 in Malaysian children: what have we learnt from the ordeal?

INTRODUCTION

In 2009, pandemic influenza A H1N1 emerged in Mexico and subsequently spread worldwide. In Malaysia, there were more than a thousand of confirmed cases among children. The general clinical characteristics of these children have been well-published. However, the description of neurologic complications is scarce.

OBJECTIVE

This study aims to describe the characteristics of neurologic manifestations and complications in a national paediatric cohort with pandemic influenza A H1N1.

METHODS

During the pandemic, children (12 years or less) admitted for novel influenza A H1N1 in 68 Malaysian public hospitals, were prospectively enrolled into national database. The clinical, laboratory and neuro-imaging data for children with neurologic manifestations, hospitalized from 15th June 2009 till 30th November 2009, was reviewed.

RESULTS

Of 1244 children with influenza A H1N1 during the study period, 103 (8.3%) presented with influenza-related neurological manifestations. The mean age of our study cohort was 4.2 years (SD: 3.3 years). Sixty percent of them were males. Sixty-nine (66.9%) were diagnosed as febrile seizures, 16 (15.5%) as breakthrough seizures with underlying epilepsy, 14 (13.6%) as influenza-associated encephalopathy or encephalitis (IAE) and 4 (3.9%) as acute necrotizing encephalopathy of childhood (ANEC). All 4 available CSF specimens were negative for influenza viral PCR. Among 14 children with brain-imaging done, 9 were abnormal (2: cerebral oedema, 4: ANEC and 3: other findings). There were four deaths and three cases with permanent neurological sequelae.

CONCLUSION

About one-tenth of children with pandemic influenza A H1N1 presented with neurologic complications. The most common diagnosis was febrile seizures. One-fifth of those children with neurologic presentation had IAE or ANEC, which carried higher mortality and morbidity. This large national study provides us useful data to better manage children with neurologic complications in the future pandemic influenza outbreaks.

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.

Alteration of liver function due to H1N1 infection: a case report

H1N1 virus is known to affect the respiratory tract. The majority of healthcare providers focus on the respiratory complications attributed to H1N1 infection, overlooking possible multi-organ involvement. We present a rare case of abnormal liver function in a child who was admitted for respiratory illness due to the H1N1 virus. There was a marked elevation in liver function tests concurrent with the respiratory disease. Our patient was treated with oseltamavir for the H1N1 infection, and the liver function levels decreased dramatically in 72 hours.

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.

Neurologic complications of influenza A(H1N1)pdm09: surveillance in 6 pediatric hospitals

OBJECTIVE

We sought to determine the range and extent of neurologic complications due to pandemic influenza A (H1N1) 2009 infection (pH1N1'09) in children hospitalized with influenza.

METHODS

Active hospital-based surveillance in 6 Australian tertiary pediatric referral centers between June 1 and September 30, 2009, for children aged <15 years with laboratory-confirmed pH1N1'09.

RESULTS

A total of 506 children with pH1N1'09 were hospitalized, of whom 49 (9.7%) had neurologic complications; median age 4.8 years (range 0.5-12.6 years) compared with 3.7 years (0.01-14.9 years) in those without complications. Approximately one-half (55.1%) of the children with neurologic complications had preexisting medical conditions, and 42.8% had preexisting neurologic conditions. On presentation, only 36.7% had the triad of cough, fever, and coryza/runny nose, whereas 38.7% had only 1 or no respiratory symptoms. Seizure was the most common neurologic complication (7.5%). Others included encephalitis/encephalopathy (1.4%), confusion/disorientation (1.0%), loss of consciousness (1.0%), and paralysis/Guillain-Barré syndrome (0.4%). A total of 30.6% needed intensive care unit (ICU) admission, 24.5% required mechanical ventilation, and 2 (4.1%) died. The mean length of stay in hospital was 6.5 days (median 3 days) and mean ICU stay was 4.4 days (median 1.5 days).

CONCLUSIONS

Neurologic complications are relatively common among children admitted with influenza, and can be life-threatening. The lack of specific treatment for influenza-related neurologic complications underlines the importance of early diagnosis, use of antivirals, and universal influenza vaccination in children. Clinicians should consider influenza in children with neurologic symptoms even with a paucity of respiratory symptoms.

Acute hepatic failure in pediatric H1N1 infection: a case report from Al-Adan Hospital, Kuwait

Liver involvement in pediatric influenza A (H1N1) infection is rare. Focused clinical evaluation and laboratory tests can rule out or identify hepatic complications early on. Here we report on a 9-year-old boy treated by the Gastroenterology, Hepatology, and Nutrition Unit of Al-Adan Hospital’s Pediatric Department. The patient, who was infected with H1N1 during the 2010 pandemic, showed symptoms of associated acute hepatic failure, was managed conservatively, and recovered completely following treatment. The author would like to draw the attention of pediatricians to the hepatic aspect of human H1N1 infection in order for them to recognize it early and treat it in a timely manner.

Influenza A 2009 H1N1 encephalitis in adults with viral RNA in cerebrospinal fluid

We present 3 cases of influenza A 2009 H1N1 encephalitis occurring in adults, corroborated by viral genome detection in cerebrospinal fluid (CSF) and evidence of meningeal inflammation on brain histopathology. This paper emphasizes the possibility of viral detection in CSF and stresses the lack of an effective treatment for neurological manifestations of influenza.

H1N1-Associated Encephalitis in a Child with Acute Myeloblastic Leukemia and Bacteremia due to Klebsiella Pneumoniae

Herein we present a neutropenic 16-year-old female with acute myeloblastic leukemia that developed recurrentgeneralized seizures while receiving antimicrobial therapy (including oseltamivir) due to pneumonia, bacteremiaof Klebsiella pneumoniae, and H1N1 infection. The patient’s seizures were controlled using assisted ventilation.Electroencephalography showed that the patient had encephalopathy. Cranial computed tomography (CT), magneticresonance imaging (MRI), and MRI angiography findings were normal. The patient fully recovered without sequelae.This case indicates that during pandemics of influenza-like diseases H1N1 infection should always be a consideration.

Fatal encephalitis associated with novel influenza A (H1N1) virus infection in a child

A 4-year-old girl presented with fever, coughing, and vomiting; followed by unconsciousness. Magnetic resonance imaging showed hyperintense changes in the thalami bilaterally, brain stem, cerebellum, and subcortical cortex. Novel influenza A (H1N1) virus was identified by polymerase chain reaction in patient's nasopharyngeal swab specimen. We reported a rare case of clinically severe, novel influenza A-associated encephalitis. Novel influenza A should be considered in the differential diagnosis in patients with seizures and mental status changes, especially during an influenza outbreak.

2009 Influenza A H1N1 infections: delays in starting treatment with oseltamivir were associated with a more severe disease

Respiratory failure has been the main severe complication described in pediatric patients with influenza A H1N1 2009 (pandemic H1N1) infection. We describe the pandemic H1N1 2009 disease in children who required hospital admission and the patients' data associated with pediatric intensive care unit admission. Respiratory failure was the main complication. Extrapulmonary manifestations were also observed. Of the 127 patients, 24 required pediatric intensive care unit admission. Four patients died. Patients admitted with chronic conditions and those in whom oseltamivir was delayed more than 72 hours had a more severe disease.

Neurological complications of pandemic influenza (H1N1) in children

The aim of this study was to determine the clinical characteristics of children demonstrating neurological complications with pandemic influenza (H1N1). We reviewed the medical and laboratory records of all children who were hospitalized with neurological symptoms and who had proven influenza virus infection by reverse transcriptase-polymerase chain reaction on nasal and throat swabs. Eight children aged between 10 months and 7 years had neurological complications due to pandemic influenza (H1N1) and five of them were female. Four of them were previously healthy; there was chronic renal failure (CRF) in one and neurologic disease in three patients. Seven of them had seizure and altered consciousness. Seven of them were followed in pediatric intensive care units. We performed lumbar puncture in four patients and their cerebrospinal fluid examinations showed pleocytosis in one and no cell in three specimens. Neuroimaging was performed in four patients and three of them had abnormalities. We diagnosed aseptic meningitis in one, acute disseminated encephalomyelitis (ADEM) in one, acute necrotizing encephalopathy (ANE) in one, meningoencephalitis in one, and status epilepticus in four patients. All patients were treated with oseltamivir and antiepileptic drugs. One patient with CRF died; four previously healthy patients recovered fully, and three patients who had neurologic disorder returned to their previous neurological status. In conclusion, during pandemic influenza (H1N1) infection, neurological complications may be seen in addition to the respiratory infection. The type of neurological involvement may be variable such as triggering seizure, aseptic meningitis, encephalitis, ADEM, and ANE. Neurological complications frequently recover fully especially in previously healthy children, but sometimes a severe clinical course occurs.

Clinical performance of three rapid diagnostic tests for influenza virus in nasopharyngeal specimens to detect novel swine-origin influenza viruses

BACKGROUND

Influenza is an important public health problem. The aim of this study was to evaluate and compare the sensitivity and specificity of three rapid diagnostic tests (SEKISUI, QuickVue Influenza A + B, and SD BIOLINE) for novel swine-origin influenza viruses (S-OIV) and seasonal influenza.

MATERIALS AND METHODS

A total of 210 nasopharyngeal swabs from unique clinical specimens were previously tested by real-time reverse transcription polymerase chain reaction (RT-PCR) assay and tested again in this study.

RESULTS AND DISCUSSION

Of these, 164 (78%) were influenza A-positive and 46 (22%) were influenza A-negative by RT-PCR. From 115 positive swabs, 80 (69.6%), 66 (57.4%), and 46 (40.0%) showed S-OIV by SEKISUI, QuickVue Influenza A + B, and SD BIOLINE, respectively. Specific positive and negative predictive values of these three commercial rapid tests were all 100%. Therefore, positive rapid influenza virus diagnosis does not require an RT-PCR confirmatory test. Conversely, only negative rapid influenza virus diagnosis should be evaluated. The SEKISUI test would be a useful diagnostic tool for screening clinical samples for influenza. Concerning the various specimen types, among 25 patients with RT-PCR-proven S-OIV infection, influenza was identified in sputum (21/25; 84.0%) and nasopharyngeal swab (15/25; 60.0%) specimens, but in only 36.0% (9/25) of throat swab specimens. Sputum and nasopharyngeal swab specimens were the most predictive of influenza virus infection, while throat swab specimens were the least predictive of influenza virus infection.

Neurologic manifestations of pediatric novel h1n1 influenza infection

Reported neurologic manifestations of novel H1N1 influenza have included seizure, meningoencephalitis, and acute necrotizing encephalopathy. We describe the first series of pediatric patients presenting during the second wave of the US novel H1N1 pandemic, with protracted seizures, severe encephalopathy/encephalitis, and acute disseminated encephalomyelitis. In addition to prominent radiographic abnormalities, we provide the first observation and description of associated cerebrospinal fluid abnormalities.

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.

Encephalitis-associated pandemic A (H1N1) 2009 in a Kuwaiti girl

OBJECTIVE

To report an 11-year-old girl with encephalitis-associated pandemic influenza A (H1N1) 2009 virus infection.

CLINICAL PRESENTATION AND INTERVENTION

An 11-year-old girl presented with a 6-day history of influenza-like illness followed by an altered mental status for 1 day. She tested positive for pandemic influenza A (H1N1) 2009 virus by PCR of her nasal swab. Her CSF analysis was completely normal, including PCR for pandemic influenza A virus. Her brain MRI and EEG showed evidence suggestive of encephalitis. She was treated with oral Oseltamivir with good recovery.

CONCLUSION

This case report shows that neurological complications can occur after respiratory tract infection with pandemic influenza A (H1N1) 2009 virus.