Spontaneous pneumomediastinum in a child due to 2009 pandemic influenza A (H1N1) virus

The 2009 pandemic influenza A (H1N1) virus spread throughout the world and caused different clinical situations. Here, we report a 4.5-year-old boy with spontaneous pneumomediastinum (SPM) complicating pneumonia associated with H1N1 virus. SPM could be associated with bronchial obstruction or necrotizing pneumonia, and the prognosis of patients with SPM associated with necrosis is worse than of patients with SPM associated with bronchial obstruction.     

A severely immunocompromised child with uncomplicated oseltamivir-resistant 2009 H1N1 pandemic influenza infection

2009 H1N1 pandemic influenza was associated with increased risk for severe disease in children and the immunosuppressed. We report a case of uncomplicated pneumonia because of infection with oseltamivir-resistant 2009 H1N1 virus in an immunosuppressed pediatric renal transplant patient. Innate immunity and/or altered viral fitness may be responsible for the mild clinical phenotype of the case.     

Clinical characteristics of children with 2009 pandemic H1N1 influenza virus infections

Background: Further understanding of the clinical manifestations, hospital course and treatment options of the 2009 pandemic H1N1 influenza virus (H1N1) is needed in preparation for future outbreaks. Methods: Seventy‐three children with polymerase‐chain‐reaction‐confirmed infections with H1N1 treated in a tertiary care medical center in Israel were included in the study. Clinical data were extracted from medical records, and analyzed by hospitalization status or the presence of underlying chronic medical conditions. Results: Prevalent symptoms were fever, cough and shortness of breath, with additional findings of conjunctivitis, seizures, chills, dizziness, purpuric rash and chest pain. Hospitalized patients were more likely to have shortness of breath (OR 26.7, 95%CI: 3.5–1150), abnormal lung auscultation (OR 11.6, 95%CI: 2.8–67), abnormal X‐ray (OR 3.3, 95%CI: 1.1–9.6), and a chronic illness (OR 5.4, 95%CI: 1.8–17), compared with non‐hospitalized ones. Disease manifestations were similar between children with or without chronic diseases. Only two (2.7%) children required intensive care, and no deaths were recorded. A high rate (18%) of thrombocytopenia was found. One child had rapid symptom resolution after intravenous immunoglobulin treatment. Conclusion: H1N1 infection follows a mild course, even in the presence of severe underlying diseases. Abnormal respiratory findings and the presence of a chronic disease probably contributed to the decision to hospitalize patients. A rapid resolution of H1N1 symptoms after intravenous immunoglobulin treatment warrants further study, and could be a possible therapeutic option for severe cases.     

Factors associated with hypoxemia in children infected with pandemic H1N1 2009 influenza virus

Background: Hypoxemia was found to be a major cause of death from pandemic H1N1 2009 influenza (pH1N1) infection. There are limited data on factors associated with hypoxemia in children infected with pH1N1 influenza virus. Methods: Factors associated with hypoxemia were investigated using univariate and multivariate analysis in 76 hospitalized pediatric patients with laboratory‐confirmed H1N1 influenza virus infection at Gyeongsang National University Hospital in Jinju, South Korea, from August 2009 to January 2010 by retrospective chart review. Results: Hypoxemia occurred in 17 children (22%), of whom three were admitted to an intensive care unit and one died. Hypoxemic patients were significantly more likely to have a higher respiratory rate, pulse rate, white blood cell count (WBC), and C‐reactive protein level, as well as a longer hospital stay. Respiratory rate and WBC count at admission were independently associated with hypoxemia as determined on multivariate analysis, and this association was found to be clinically significant. Conclusion: Although a higher WBC count and respiratory rate may not be specific for pHINI but represent the degree of disease severity for any infectious respiratory disease in general, clinicians can use these parameters at admission as useful, early indicators of disease severity in pediatric pH1N1 infection.     

Acute necrotizing encephalopathy in a child with H1N1 influenza infection

Since the World Health Organization declared a global pandemic of novel influenza A H1N1 in June 2009, there has been a sustained rise in the number of cases of this strain of influenza. Although most cases are mild with complete and uneventful recovery, multiple cases of severe infection with complications including death have been reported. To the best of our knowledge, the majority of fatal outcomes in the United States have been related to pulmonary complications. We report a 12-year-old girl infected with influenza A H1N1 whose clinical course was complicated by rapid progressive neurologic deterioration and striking CT and MRI findings consistent with acute necrotizing encephalopathy (ANE). To our knowledge this has not been reported in the pediatric radiology literature. We hope this case will alert radiologists to this complication and familiarize radiologists with imaging findings that herald ANE.     

Hemophagocytic lymphohistiocytosis associated with 2009 pandemic influenza A (H1N1) virus infection

Hemophagocytic lymphohistiocytosis (HLH) has not been described earlier in the context of 2009 pandemic influenza A (H1N1) virus infection, although certain populations are thought to be at risk for complicated pandemic influenza A disease. Here, we report the second case of HLH after infection with the influenza A H1N1 virus treated with peroral oseltamivir successfully.     

Aseptic meningitis in a child due to 2009 pandemic influenza A (H1N1) infection

Neurologic manifestations of seasonal influenza 2009 pandemic influenza A (H1N1) are now known to include encephalitis, acute disseminated encephalomyelitis, Guillain-Barré syndrome, transverse myelitis, and acute necrotizing encephalopathy. We report a case of 2009 pandemic influenza A (H1N1) meningitis in a previously healthy six-year-old girl who presented with fever, headache, abdominal pain, and vomiting. The infection was confirmed via nasopharyngeal and throat swabs. She was treated with oseltamivir successfully. To our knowledge, she is the first child diagnosed as pandemic influenza A (H1N1) meningitis.     

Myocarditis in a pediatric case of pandemic 2009H1N1 influenza

We report a 6‐year‐old boy with no major disease history or allergic conditions initially presented with pneumonia, progressed to acute respiratory distress syndrome and acute myocarditis caused by pandemic 2009H1N1 influenza diagnosed with RT‐PCR testing, successfully managed with mechanical ventilation and percutaneous cardiopulmonary support system. Marked transient elevation of IgE in acute phase of the disease and the subsequent diagnosis of atopic asthma in our patient suggested a possible role of an underlying allergic condition in the clinicopathological process. Critically ill 2009H1N1‐infected patient with acute respiratory failure should carefully be physiologically monitored together with serial assessment of biomarkers aiming at a favorable cardiac outcome by giving the timely diagnosis and intervention.     

Hemorrhagic shock syndrome with encephalopathy

The occurrence in a previously healthy infant of sudden febrile encephalopathy with shock and metabolic acidosis associated with liver and renal failure and bloody watery diarrhea has been reported by several authors in recent years. We report the same association in a 3 1/2 month-old infant. We discuss the similarities between this clinical picture and malignant hyperthermia and Reye syndrome.     

出血性休克与脑病综合征

出血性休克与脑病综合征(HSES)于1983年由Levin首先报道并加以命名。HSES发病迅速,病死率高,生存者易留有严重的神经系统后遗症,其临床特点是突发的抽搐和昏迷、休克、弥漫性血管内凝血、水样腹泻、代谢性酸中毒、肝肾功能障碍。该文对HSES的临床研究进展作一综述,以提高对该病的认识和治疗水平。     

IgG3 deficiency and severity of 2009 pandemic H1N1 influenza

Background: The severity of the 2009 pandemic H1N1 influenza (H1N1 pdm 09) in immune deficient children is unknown. The aim of the present study was to investigate this in a case of complete IgG3 deficiency complicated by pneumonia and asthma attack. Methods: The clinical parameters of the IgG3 deficiency patient were compared with those of four control patients using 95% confidence intervals. These control patients were selected from 71 patients admitted due to pneumonia or bronchitis caused by H1N1 pdm 09, and were chosen according to age, absence of pretreatment with oseltamivir before admission, presence of a past history of asthma, use of antibiotics, and combination of inhalation of a beta2 agonist and treatment with i.v. methylprednisolone for asthma attack. Results: The IgG3 deficiency patient had significantly longer duration of admission and period of oseltamivir, with a significantly decreased pulse oxygen saturation and increased maximum serum C‐reactive protein, creatine kinase and urinary excretion of β2‐microglobulin/creatinine, compared with the controls (P < 0.05). Conclusions: Complete IgG3 deficiency is possibly associated with severity of the clinical course of pneumonia and asthma attack in children suffering from H1N1 pdm 09.     

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目的通过观察3例儿童2009年新型甲型H1N1流感病毒急性坏死性脑病(ANE)脑组织病理性改变,探讨ANE脑组织可能的免疫病理反应。方法对2009年11月至2010年1月深圳儿童医院3例因ANE死亡患儿脑组织行HE染色形态学观察、髓鞘染色、小胶质细胞石蜡切片染色及免疫组织化学EliVision法检测分析。结果 ANE患儿脑组织小胶质细胞棘突消失变为圆形,髓鞘染色证实脑实质神经纤维呈脱髓鞘改变,经Naomenke及Feigin染色法证实小胶质细胞处于激活状态,免疫组化发现ANE患儿小胶质细胞产生TNF-α和IFN-α,脑组织未见淋巴细胞、中性粒细胞浸润。结论小胶质细胞异常增生可能是导致ANE发病的原因之一。     

Natural history of pandemic H1N1 2009 influenza infection in healthy pediatric outpatients

ObjectiveThe pandemic influenza H1N1 2009 (pH1N1) virus is expected to remain a prominent circulating strain in the current and subsequent influenza seasons. The objective of this study was to compare the clinical course of infection with laboratory-confirmed pH1N1 and seasonal influenza A and B in a cohort of previously healthy children managed in the outpatient setting without antiviral therapy.MethodsPreviously healthy children 17 years of age or younger were prospectively enrolled during the first wave of the 2009 pandemic (May–July 2009) and the 2 preceding influenza seasons from a single primary care physician office and a tertiary children’s hospital emergency department. Inclusion criteria were: age ≤17 years; laboratory-confirmed influenza; and not receiving antiviral agents. Follow-up telephone interviews were conducted approximately 2 days and 14 days after presentation to assess symptom duration.ResultsA total of 251 patients (101 with pH1N1, 90 with seasonal influenza A, 60 with seasonal influenza B) were included. Presenting symptoms and duration of symptoms associated with pH1N1 were similar to those with seasonal influenza. Median fever duration in pH1N1 was 3 days and had resolved within 8 days in 95% of patients. Among patients with pH1N1, abnormalities on chest auscultation (10 of 101), the hospitalization rate (2 of 101), the proportion of children receiving intravenous fluid therapy (1 of 101) or supplemental oxygen (1 of 101) were not significantly different from patients with seasonal influenza.ConclusionsIn most children without underlying risk factors for severe influenza, pH1N1 virus causes an uncomplicated respiratory tract illness, no more severe than seasonal influenza.     

Neurological complications and pandemic influenza A (H1N1) virus infection

Aim: To report on a different clinical course of pandemic influenza A (H1N1) infection among children who were neurologically impaired before the acute onset of the disease, in comparison with children who were neurologically intact. Methods: In a period of 6 months, six children with neurological complications associated with pandemic A (H1N1) infection were identified in a single institution paediatric emergency room. The children suffered from seizures or altered mental status during pandemic A (H1N1) infection. All children underwent extensive clinical and laboratory assessment. Three children were neurologically impaired before the acute onset of the H1N1 infection. The other three were neurologically intact before the acute viral infection. Results: In all six patients, pandemic influenza A (H1N1) viral RNA was detected in nasopharyngeal specimens but none in the cerebrospinal fluid. Five children fully recovered or returned to baseline at discharge. The clinical course of the disease and recovery were different between the children who were neurologically impaired before the acute viral infection and those who were neurologically intact. Conclusions: It is possible that children with various neurological conditions are in a higher risk to develop further neurological complications during pandemic influenza A (H1N1) infection.