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.     

Acute disseminated encephalomyelitis following 2009 H1N1 influenza vaccine

Acute disseminated encephalomyelitis (ADEM) is an immune‐mediated inflammatory disorder of the central nervous system. We describe a previously healthy 2‐year‐old boy with ADEM, who exhibited high fever, lethargy, and recurrent seizures at 25 days after H1N1 influenza vaccination. To our knowledge, there has been only one report of ADEM following the 2009 H1N1 influenza vaccine, although such vaccination is accompanied with optic neuritis apart from this case. Thus, this is the first case of ADEM without optic neuritis, following the 2009 H1N1 influenza vaccination. Although vaccine‐associated ADEM remains rare, the increasing number of influenza vaccinations might increase the incidence of ADEM. We still need to pay attention to the occurrence of ADEM and treat patients with steroid therapy.     

Rhabdomyolysis associated with influenza A/H1N1 2009 infection in a pediatric patient

The influenza A/H1N1 2009 epidemic has spread to many countries since 2009, including Japan. We report an immune‐competent child involving rhabdomyolysis and compartment syndrome associated with influenza A/H1N1 2009. The patient was demonstrated rhabdomyolysis with myoglobinuria, hyperkalemia, cardiac dysfunction and compartment syndrome that arose during convalescence from influenza A/H1N1 2009 infection. Although RT‐PCR of muscle tissue yielded negative results for influenza A/H1N1 2009 RNA and no viral positive‐antigen cells were detected in the muscle lesions, the clinical picture suggested rhabdomyolysis associated with influenza A/H1N1. Rhabdomyolysis should be considered in the evaluation of muscle symptoms such as myalgia associated with novel influenza A/H1N1 2009 virus infection, particularly in critically ill patients.     

Pediatric hospitalizations with influenza A infection during the 2009–2010 pandemic in five hospitals in Japan

Background: The aim of this study was to identify the clinical characteristics of hospitalized children with the 2009 pandemic influenza virus infection in Japan. Methods: We retrospectively reviewed cases of hospitalized children younger than 16 years with laboratory‐confirmed influenza A virus infection during the 2009–2010 pandemic season in five hospitals in Japan. Results: A total of 515 cases were included in the analysis. The median age was 6.3 years (range 0–15), and 216 subjects (41.9%) had one or more underlying medical conditions. There were no fatalities, but 16 patients (3.1%) required intensive care. More than 93% of the subjects received neuraminidase inhibitors, and more than 87% received these medications within 48 h of the onset of symptoms. Approximately 80% of all subjects were admitted to hospital within 48 h of the onset of symptoms. Conclusions: There were no fatalities, and the proportion of patients with serious illness was substantially lower than previously reported from other countries. Good access to medical services and proactive treatment may have contributed to the lower disease burden of the 2009 influenza pandemic on Japanese children.     

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.     

Novel inpatient surveillance in tertiary paediatric hospitals in New South Wales illustrates impact of first-wave pandemic influenza A H1N1 (2009) and informs future health service planning

Aim: To document the impact of pandemic influenza A H1N1 (2009) in New South Wales (NSW) children's hospitals. Methods: A novel surveillance system, Paediatric Active Enhanced Disease Surveillance (PAEDS), identified hospitalised children <15 years with laboratory‐proven influenza (1 June–30 September 2009) in the three children's hospitals in NSW: Children's Hospital at Westmead (CHW), Sydney Children's Hospital, John Hunter Children's Hospital. Clinical characteristics, management and complications were documented, and at CHW comparison made with 2007 data. Results: The 324 children identified represented 1802 hospital bed‐days and 230 PICU bed‐days. Most (73.1%) children had H1N1, one had an oseltamivir‐resistant isolate. Median age was 2.5 years: 65% were <5 years. Although 80.9% had cough, 8.0% had no respiratory symptoms. Complications occurred in 34.6%, of whom 56% were previously healthy. Only 50% received antivirals. Forty children (12.3%) were admitted to PICU: one child with H1N1 died. At CHW, comparison between 2009 and 2007 showed nearly twice the total number of admissions (226 vs. 122) and PICU admissions (22 vs. 13), but no deaths either year. Vomiting was more frequent in 2009 than 2007 (38.5% vs. 13.1%; P = 0.0001) as were neurological complications (11.4% vs. 2.4%; P = 0.0027) but length of hospital and PICU stay were similar. Conclusions: PAEDS is a valuable surveillance tool that documented the impact of the H1N1 (2009) pandemic in NSW children's hospitals. High numbers of complications, often in previously well children, suggest an important role for early diagnosis, antiviral therapy and influenza vaccination. Observed regional differences identify areas potentially at greater risk in a subsequent wave.     

Oseltamivir-resistant 2009 H1N1 influenza pneumonia during therapy in a renal transplant recipient

The emergence of oseltamivir-resistant 2009 H1N1 influenza virus (conferred by the H275Y substitution in NA) during therapy or prophylaxis in immunocompromised patients is a serious concern. The optimal therapy for immunosuppressed patients with oseltamivir-resistant 2009 H1N1 influenza virus is unknown and few options exist. We report a 10-yr-old recipient of kidney transplant who was hospitalized with oseltamivir-resistant 2009 H1N1 influenza pneumonia complicated by severe respiratory failure, ARDS, and renal failure requiring institution of ECMO and CRRT. On presentation, treatment with oseltamivir (second course) and broad-spectrum antibiotics was initiated. Immunosuppressive agents were stopped on hospital day (d) 2. On hospital d 7, given his critical status, immunocompromised state, and difficulty in obtaining intravenous zanamivir, after obtaining ethical approval and parental consent, he was treated with intravenous peramivir (through an Emergency Investigational New Drug Application) for two wk. He tolerated the regimen well and his clinical status improved gradually. Several factors may have contributed to virus clearance and survival including recovery of the immune system, aggressive critical care support, and administration of peramivir. Ongoing surveillance is essential to monitor how oseltamivir-resistant H275Y mutant viruses may evolve in the future.     

The first case of H5N1 avian influenza infection in a human with complications of adult respiratory distress syndrome and Reye's syndrome

Avian influenza virus was not known to cause systemic infection in humans before. We report a 3-year-old boy with good past health who developed pneumonia caused by H5N1 avian influenza A virus (A/Hong Kong/156/97). The virus was isolated from a tracheal aspirate. There were complications of Reye's syndrome, adult respiratory distress syndrome, and multiple organ system failure. He had a history of receiving aspirin. His adult respiratory distress syndrome did not respond to endotracheal surfactant replacement therapy. He died 6 days after admission. Clinicians should be alert to the importance of a new human influenza strain.     

小儿甲型H1N1流感危重症诊治体会

目的 探讨小儿甲型H1N1流感危重症患儿的发病特点及治疗措施.方法 2009年10月5日至11月15日期间我院PICU收治11例出现甲型H1N1流感样症状合并重症肺炎、急性呼吸窘迫综合征(ARDS)患儿,对其发病特点、治疗方法及转归等资料进行分析.结果 11例甲型H1N1流感样患儿合并重症肺炎、ARDS,其中6例经咽拭子检测甲型H1N1流感病毒核酸阳性.患儿平均年龄3.9岁(10个月～11岁).所有患儿都表现为发热和呼吸系统症状,从发病到出现危重症状的时间为5～10 d.6例行机械通气治疗.目前全部病例存活,无一例死亡.6例机械通气患儿已有4例安全脱机,2例仍在机械通气中.结论 重症甲型H1N1流感患儿病初为流感症状,无特殊临床表现;病情可在短时间内迅速加重,重症患儿以呼吸困难、低氧血症为突出表现;婴幼儿可伴有嗜睡、烦躁等神经系统症状;重症患儿肺部病变广泛,进展迅速,可在短时间内出现纵隔及皮下气肿、ARDS甚或肺出血并随之出现多脏器功能障碍综合征.     

Serum KL‐6 and surfactant protein D in children with 2009 pandemic H1N1 influenza infection

Background: A global pandemic influenza A (H1N1) outbreak occurred in 2009. Rapid progress of respiratory distress is one of the characteristic features of pandemic influenza A (H1N1) infection. The physiologic mechanism causing hypoxia in pandemic influenza A (H1N1) infection, however, has not been elucidated. Methods: The serum levels of KL‐6 and surfactant protein D (SP‐D) were evaluated in 21 cases of pandemic influenza A (H1N1) infection associated with chest radiographic abnormality in order to estimate alveolar involvement. The clinical features were also analyzed. Results: All of the patients had high fever, and rapidly progressed to respiratory distress within several days of disease onset. Despite mild radiographic abnormality in these patients, dyspnea was severe and they had low blood oxygen saturation levels. Many of the patients had a history of allergic diseases including asthma. Serum KL‐6 and SP‐D levels on admission were 191 ± 69 U/mL and 32.6 ± 18.9 ng/mL, respectively. These two levels were still below the upper normal limit 1 week later. There were no clear relationships between specific clinical symptoms and KL‐6 or SP‐D levels. All patients were treated with oseltamivir and/or zanamivir, and improved without mechanical ventilation management. Conclusion: KL‐6 and SP‐D elevation were not significant in pandemic influenza A (H1N1) infection associated with chest radiographic abnormality. In pandemic influenza A (H1N1) infection, alveolar involvement was estimated to be little, and severe respiratory distress was probably caused by obstruction of peripheral bronchi.     

Perception,attitudes and knowledge regarding the 2009 swine‐origin influenza A (H1N1) virus pandemic among health‐care workers in Australia

Aim: To determine the perceptions, attitudes and knowledge of Australian health‐care workers (HCWs) regarding the novel, swine‐origin influenza A (H1N1) virus (S‐OIV) outbreak that reached the country in early May 2009. Methods: Self‐administered, anonymous Web‐based survey conducted during the early stages of the S‐OIV pandemic. Participants comprised hospital‐ and community‐based medical and nursing staff, medical students, allied health professionals, laboratory staff and administrative personnel. Results: Of the 947 participants surveyed, 59.4% were not convinced that Australia was sufficiently prepared for an influenza pandemic. Only 17.6% of the participants stated they were prepared to work unconditionally during a pandemic; 36.5% stated they would work if they had access to antiviral treatment; 27.9% would if provided with antiviral prophylaxis; and 7.5% would refuse to work. In addition, 37.5% of the participants responded they would refuse or avoid being involved in screening suspected cases. A total of 47.7% admitted to possessing a personal supply of antivirals or having considered this option. Only 48.0% provided a realistic estimate of the mortality associated with an influenza pandemic at a population level. HCWs overestimating the mortality risk and HCWs believing the efficacy of antiviral prophylaxis to be low were significantly less likely to be prepared to work (P= 0.04 and P= 0.0004, respectively). Conclusions: To ensure adequate staffing during an influenza pandemic, preparedness plans should anticipate significant levels of absenteeism by choice. Interventions aimed at increasing staff retention during a pandemic require further evaluation.     

儿童2009甲型H1N1流感相关神经系统并发症报道

报道儿童2009甲流H1N1流感相关神经系统并发症的临床特征。方法　对深圳市儿童医院2009 - 11 - 04 - 2010 - 01 - 19因2009甲型H1N1流感住院,并发神经系统并发症的21例患儿进行前瞻性调研,对其临床特征及转归进行总结。结果　在150例儿童危重症2009甲型H1N1流感住院患儿中,神经系统并发症的发生率为14.0%（21/150）,其中脑病18例（85.7%）,惊厥2例（9.5%）,脑炎1例（4.7%）。男14例,女7例;年龄中位数为5岁。12例（57%）入住ICU监护,6例（28.5%）接受气管插管及机械通气。17例80.9%）痊愈出院,1例仍在住院,3例（14%）死于脑病。结论　2009甲型H1N1流感相关神经系统并发症发生率高,严重脑病患儿可以导致死亡。随着2009甲型H1N1流感的流行,这一结果应该引起广泛关注。     

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.