Influenza B-induced longitudinally extensive transverse myelitis and bithalamic acute disseminated encephalomyelitis

In the COVID-era, other viral pathogens, like influenza B, gain less attention in scientific reporting. However, influenza still is endemic, and rarely affects central nervous system (CNS). Here, we report the case of a 35-year-old male who presented with fever since 1 week, and developed acute ascending flaccid paralysis and urinary retention. The clinical presentation of paraparesis in combination with the inflammation proven by the lumbar puncture, and the MRI full spine, fulfilled the diagnostic criteria of longitudinally extensive transverse myelitis (LETM). In this case, it is most likely based on a post-viral Influenza type B. Additionally, the brain MRI showed a necrotizing encephalopathy bilaterally in the thalamus. Both locations of inflammatory disease were part of one auto-immune-mediated, monophasic CNS disorder: influenza-induced ADEM which is very unique, fortunately with favorable outcome.

CT findings of 144 in-hospital patients with influenza pneumonia: A retrospective analysis

BACKGROUND/PURPOSE

Patients with influenza infection during their period of admission may have worse computed tomography (CT) manifestation according to the clinical status. This study aimed to evaluate the CT findings of in-hospital patients due to clinically significant influenza pneumonia with correlation of clinical presentations.

METHODS

In this retrospective, single center case series, 144 patients were included. All in-hospital patients were confirmed influenza infection and underwent CT scan. These patients were divided into three groups according to the clinical status of the most significant management: (1) without endotracheal tube and mechanical ventilator (ETTMV) or extracorporeal membrane oxygenation (ECMO); (2) with ETTMV; (3) with ETTMV and ECMO. Pulmonary opacities were scored according to extent. Spearman rank correlation analysis was used to evaluate the correlation between clinical parameters and CT scores.

RESULTS

The predominant CT manifestation of influenza infection was mixed ground-glass opacity (GGO) and consolidation with both lung involvement. The CT scores were all reach significant difference among all three groups (8.73 ± 6.29 vs 12.49 ± 6.69 vs 18.94 ± 4.57, p < 0.05). The chest CT score was correlated with age, mortality, and intensive care unit (ICU) days (all p values were less than 0.05). In addition, the CT score was correlated with peak lactate dehydrogenase (LDH) level and peak C-reactive protein (CRP) level (all p values were less than 0.05). Concomitant bacterial infection had higher CT score than primary influenza pneumonia (13.02 ± 7.27 vs 8.95 ± 5.99, p < 0.05).

CONCLUSION

Thin-section chest CT scores correlated with clinical and laboratory parameters in in-hospital patients with influenza pneumonia.

[Relationship between the lung ultrasound and the clinical severity of the patient with seasonal flu]

INTRODUCTION

The seasonal flu is a very important reason for consultation every winter. Symptoms can quickly progress to severe pneumonia. Currently, few tools exist to assess the clinical severity of patients. The aim of this study is to demonstrate the role of lung ultrasound as a marker of severity in patients with influenza.

METHODS

79 patients who arrived at the emergency department with flu-like symptoms were included. A pulmonary ultrasound looking for an interstitial syndrome or consolidation was performed. The qSOFA, the SOFA, the saturation, the PaO2/FiO2 ratio, the oxygen needs, the destination of the patient made it possible to establish the seriousness of the pathology of the patient. Ultrasound was then compared to these different tools.

RESULTS

The more the ultrasound became pathological, the more we observed a proportion of qSOFA (p = 0.001) and pathological SOFA (p = 0.009). Most patients with acute respiratory distress syndrome have pathological ultrasound (p < 0.001). The average admission saturation is 89.2 % in the "pathological ultrasound" group compared to 95.8 % in the "normal ultrasound" group (p < 0.001). Patients who required invasive therapies had pathological ultrasound (p < 0.001). Of the 28 patients with pathological ultrasound, 24 required hospitalization (p < 0.001).

CONCLUSION

Lung ultrasound is a major asset for assessing the severity of the patient with seasonal flu. In addition, ultrasound allows better monitoring of the patient by being able to influence the destination of the latter towards a return home or monitoring in intensive care.

Comparison of Ultrasound and CT Imaging for the Diagnosis of Coronavirus Disease and Influenza A Pneumonia

OBJECTIVE

The outbreak of coronavirus disease (COVID-19) coincided with the season of influenza A pneumonia, a common respiratory infectious disease. Therefore, this study compared ultrasonography and computed tomography (CT) for the diagnosis of the two diseases.

METHODS

Patients with COVID-19 or influenza A infection hospitalized at our hospital were included. The patients were examined by ultrasonography every day. The CT examination results within 1 day before and after the day of the highest ultrasonography score were selected as the controls. The similarities and differences between the ultrasonography and CT results in the two groups were compared.

RESULTS

There was no difference between the ultrasonography and CT scores (P = .307) for COVID-19, while there was a difference between ultrasonography and CT scores for influenza A pneumonia (P = .024). The ultrasonography score for COVID-19 was higher than that for influenza A pneumonia (P = .000), but there was no difference between the CT scores (P = .830). For both diseases, there was no difference in ultrasonography and CT scores between the left and right lungs; there were differences between the CT scores of the upper and middle lobes, as well as between the upper and lower lobes of the lungs; however, there was no difference between the lower and middle lobes of the lungs.

CONCLUSION

Ultrasonography is equivalent to the gold standard CT for diagnosing and monitoring the progression of COVID-19. Because of its convenience, ultrasonography has important application value. Furthermore, the diagnostic value of ultrasonography for COVID-19 is higher than that for influenza A pneumonia.

[Chinese expert consensus on the imaging diagnosis of severe pneumonia of influenza A (H1N1) flu]

In March 2009, influenza A(H1N1) flu broke out and spread rapidly worldwide, and it has been circulating in local areas with various scales since then. Particularly, the outbreak and prevalence have occurred in China during 2023 extensively. At present, there is an absence of unified consensus on imaging diagnosis of severe influenza A (H1N1) flu pneumonia, which is not conducive to the standardized imaging diagnosis and clinical practice. Chinese experts including the Infection and Inflammatory Radiology Committee of the Chinese Research Hospital Association jointly formulate this consensus based on numerous references related to influenza A (H1N1) flu, meanwhile combining the methodological requirements of evidence-based medicine for guideline and standard formulation. This consensus aims to form a consensus on the diagnostic evidence, recommended imaging methods, diagnostic standard and differential diagnosis of severe influenza A(H1N1) flu pneumonia, and it is ought to provide clear diagnostic information and basis for relevant professional physicians and guide the clinical diagnosis and treatment of severe pneumonia caused by influenza A(H1N1) flu.

Differentiation of Chest CT Findings Between Influenza Pneumonia and COVID-19: Interobserver Agreement Between Radiologists

OBJECTIVES

To investigate the chest CT and clinical characteristics of COVID-19 pneumonia and H1N1 influenza, and explore the radiologist diagnosis differences between COVID-19 and influenza.

MATERIALS AND METHODS

This cross-sectional study included a total of 43 COVID-19-confirmed patients (24 men and 19 women, 49.90 ± 18.70 years) and 41 influenza-confirmed patients (17 men and 24 women, 61.53 ± 19.50 years). Afterwards, the chest CT findings were recorded and 3 radiologists recorded their diagnoses of COVID-19 or of H1N1 influenza based on the CT findings.

RESULTS

The most frequent clinical symptom in patients with COVID-19 and H1N1 pneumonia were dyspnea (96.6%) and cough (62.5%), respectively. The CT findings showed that the COVID-19 group was characterized by GGO (88.1%), while the influenza group had features such as GGO (68.4%) and consolidation (66.7%). Compared to the influenza group, the COVID-19 group was more likely to have GGO (88.1% vs. 68.4%, p = 0.032), subpleural sparing (69.0% vs. 7.7%, p <0.001) and subpleural band (50.0% vs. 20.5%, p = 0.006), but less likely to have pleural effusion (4.8% vs. 33.3%, p = 0.001). The agreement rate between the 3 radiologists was 65.8%.

CONCLUSION

Considering similarities of respiratory infections especially H1N1 and COVID-19, it is essential to introduce some clinical and para clinical modalities to help differentiating them. In our study we extracted some lung CT scan findings from patients suspected to COVID-19 as a newly diagnosed infection comparing with influenza pneumonia patients.

Ultrasound and Influenza: The Spectrum of Lung and Cardiac Ultrasound Findings in Patients with Suspected Influenza A and B

In patients with influenza, cardiac and lung ultrasound may help determine the severity of illness and predict clinical outcomes. To determine the ultrasound characteristics of influenza and define the spectrum of lung and cardiac findings in patients with suspected influenza A or B, we conducted a prospective observational study in patients presenting to the emergency department at a tertiary care academic institution. An ultrasound protocol consisting of cardiac, lung and inferior vena cava scans was performed within 6 h of admission. We compared the ultrasound findings in cases with positive and negative influenza polymerase chain reaction, while controlling for comorbidities. We enrolled 117 patients, 41.9% of whom (49/117) tested positive for influenza. In those with influenza, ultrasound confirmed preserved left ventricular and right ventricular (RV) function in 81.3% of patients. The most common cardiac pathology was RV dilation (10.4%), followed by left ventricular systolic dysfunction (8.3%). Patients with negative influenza polymerase chain reaction with RV dysfunction demonstrated higher hospital admission than those those with normal RV function (45.1%, 23/51, vs. 17.9%, 5/28; p = 0.016). B-lines were prevalent in both influenza and non-influenza groups (40.8% and 69.1%, respectively; p = 0.013). Lung consolidation was identified in only 8.25% of patients with influenza. In conclusion, in patients with influenza we were unable to define distinct ultrasound features specific to influenza A or B, suggesting that ultrasound may not be beneficial in diagnosing influenza nor in evaluating its severity.

Combining initial chest CT with clinical variables in differentiating coronavirus disease 2019 (COVID-19) pneumonia from influenza pneumonia

Coronavirus disease 2019 (COVID-19) has spread in more than 100 countries and regions around the world, raising grave global concerns. COVID-19 has a similar pattern of infection, clinical symptoms, and chest imaging findings to influenza pneumonia. In this retrospective study, we analysed clinical and chest CT data of 24 patients with COVID-19 and 79 patients with influenza pneumonia. Univariate analysis demonstrated that the temperature, systolic pressure, cough and sputum production could distinguish COVID-19 from influenza pneumonia. The diagnostic sensitivity and specificity for the clinical features are 0.783 and 0.747, and the AUC value is 0.819. Univariate analysis demonstrates that nine CT features, central-peripheral distribution, superior-inferior distribution, anterior-posterior distribution, patches of GGO, GGO nodule, vascular enlargement in GGO, air bronchogram, bronchiectasis within focus, interlobular septal thickening, could distinguish COVID-19 from influenza pneumonia. The diagnostic sensitivity and specificity for the CT features are 0.750 and 0.962, and the AUC value is 0.927. Finally, a multivariate logistic regression model combined the variables from the clinical variables and CT features models was made. The combined model contained six features: systolic blood pressure, sputum production, vascular enlargement in the GGO, GGO nodule, central-peripheral distribution and bronchiectasis within focus. The diagnostic sensitivity and specificity for the combined features are 0.87 and 0.96, and the AUC value is 0.961. In conclusion, some CT features or clinical variables can differentiate COVID-19 from influenza pneumonia. Moreover, CT features combined with clinical variables had higher diagnostic performance.

Clinical Characteristics and CT Findings in 148 Non-COVID-19 Influenza-Like Illness Cases: A Retrospective Control Study

Background: This study was to collect clinical features and computed tomography (CT) findings of Influenza-Like Illness (ILI) cases, and to evaluate the correlation between clinical data and the abnormal chest CT in patients with the Influenza-Like Illness symptoms. Methods: Patients with the Influenza-Like Illness symptoms who attended the emergency department of The Six Medical Center of The PLA General Hospital from February 10 to April 1, 2020 were enrolled. Clinical and imaging data of the enrolled patients were collected and analyzed. The association between clinical characteristics and abnormal chest CT was also analyzed. Results: A total of 148 cases were enrolled in this study. Abnormalities on chest CT were detected in 61/148 (41.2%) patients. The most common abnormal CT features were as follows: patchy consolidation 22/61(36.1%), ground-glass opacities 21/61(34.4%), multifocal consolidations 17/61(27.9%). The advanced age and underlying diseases were significantly associated with abnormal chest CT. Conclusions: Abnormal chest CT is a common condition in Influenza-Like Illness cases. The presence of advanced age and concurrent underlying diseases is significantly associated with abnormal chest CT findings in patients with ILI symptoms. The chest CT characteristic of ILI is different from the manifestation of COVID-19 infection, which is helpful for differential diagnosis.

Co-infection of COVID-19 and influenza A in a hemodialysis patient: a case report

BACKGROUND

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus that was first discovered in December 2019 in Wuhan, China. With the growing numbers of community spread cases worldwide, the World Health Organization (WHO) declared the COVID-19 outbreak as a pandemic on March 11, 2020. Like influenza viruses, SARS-CoV-2 is thought to be mainly transmitted by droplets and direct contact, and COVID-19 has a similar disease presentation to influenza. Here we present a case of influenza A and COVID-19 co-infection in a 60-year-old man with end-stage renal disease (ESRD) on hemodialysis.

CASE PRESENTATION

A 60-year-old man with ESRD on hemodialysis presented for worsening cough, shortness of breath, and diarrhea. The patient first developed a mild fever (37.8 °C) during hemodialysis 3 days prior to presentation and has been experiencing worsening flu-like symptoms, including fever of up to 38.6 °C, non-productive cough, generalized abdominal pain, nausea, vomiting, and liquid green diarrhea. He lives alone at home with no known sick contacts and denies any recent travel or visits to healthcare facilities other than the local dialysis center. Rapid flu test was positive for influenza A. Procalcitonin was elevated at 5.21 ng/mL with a normal white blood cell (WBC) count. Computed tomography (CT) chest demonstrated multifocal areas of consolidation and extensive mediastinal and hilar adenopathy concerning for pneumonia. He was admitted to the biocontainment unit of Nebraska Medicine for concerns of possible COVID-19 and was started on oseltamivir for influenza and vancomycin/cefepime for the probable bacterial cause of his pneumonia and diarrhea. Gastrointestinal (GI) pathogen panel and Clostridioides difficile toxin assay were negative. On the second day of admission, initial nasopharyngeal swab came back positive for SARS-CoV-2 by real-time reverse-transcriptase polymerase chain reaction (RT-PCR). The patient received supportive care and resumed bedside hemodialysis in strict isolation, and eventually fully recovered from COVID-19.

CONCLUSIONS

We presented a case of co-infection of influenza and SARS-CoV-2 in a hemodialysis patient. The possibility of SARS-CoV-2 co-infection should not be overlooked even when other viruses including influenza can explain the clinical symptoms, especially in high-risk patients.

A rapid screening classifier for diagnosing COVID-19

Rationale: Coronavirus disease 2019 (COVID-19) has caused a global pandemic. A classifier combining chest X-ray (CXR) with clinical features may serve as a rapid screening approach. Methods: The study included 512 patients with COVID-19 and 106 with influenza A/B pneumonia. A deep neural network (DNN) was applied, and deep features derived from CXR and clinical findings formed fused features for diagnosis prediction. Results: The clinical features of COVID-19 and influenza showed different patterns. Patients with COVID-19 experienced less fever, more diarrhea, and more salient hypercoagulability. Classifiers constructed using the clinical features or CXR had an area under the receiver operating curve (AUC) of 0.909 and 0.919, respectively. The diagnostic efficacy of the classifier combining the clinical features and CXR was dramatically improved and the AUC was 0.952 with 91.5% sensitivity and 81.2% specificity. Moreover, combined classifier was functional in both severe and non-serve COVID-19, with an AUC of 0.971 with 96.9% sensitivity in non-severe cases, which was on par with the computed tomography (CT)-based classifier, but had relatively inferior efficacy in severe cases compared to CT. In extension, we performed a reader study involving three experienced pulmonary physicians, artificial intelligence (AI) system demonstrated superiority in turn-around time and diagnostic accuracy compared with experienced pulmonary physicians. Conclusions: The classifier constructed using clinical and CXR features is efficient, economical, and radiation safe for distinguishing COVID-19 from influenza A/B pneumonia, serving as an ideal rapid screening tool during the COVID-19 pandemic.

Comparison of clinical, laboratory, and radiological characteristics between SARS-CoV-2 infection and community-acquired pneumonia caused by influenza virus: A cross-sectional retrospective study

Coronavirus disease 2019 (COVID-19) is the most important global public health issue that we currently face. We aimed to explore the clinical features of patients with COVID-19 and compared them with those of hospitalized community-acquired pneumonia (CAP) patients caused by influenza virus during the same period.From Jan 1, to Mar 4, 2020, patients with COVID-19 or CAP caused by influenza virus who were admitted to the First Affiliated Hospital of Xiamen University were consecutively screened for enrollment.A total of 35 COVID-19 patients and 22 CAP patients caused by influenza virus were included in this study. Most of COVID-19 patients had characteristics of familial clustering (63%), however, in the other group, there was no similar finding. The percentages of patients with a high fever (the highest recorded temperature was ≥39.0°C; 11% vs 45% [COVID-19 vs CAP groups, respectively]), dyspnea (9% vs 59%), leukocytosis (3% vs 32%), elevated C-reactive protein concentrations (>10 mg/L, 48% vs 86%), elevated procalcitonin levels (>0.1 ng/ml, 15% vs 73%), PaO2/FiO2 <200 mm Hg (4% vs 22%), and infiltration on imaging (29% vs 68%) in the COVID-19 group were less than those same indices in the hospitalized CAP patients caused by influenza virus. Ground-glass opacity with reticular pattern (63%) and interlobular septal thickening (71%) in chest CT were commonly observed in the COVID-19 group.COVID-19 and CAP caused by influenza virus appear to share some similarities in clinical manifestaions but they definitely have major distinctions. Influenza infection remains a health problem even during COVID-19 pandemic.

Comparison of hospitalized patients with pneumonia caused by COVID-19 and influenza A in children under 5 years

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The clinical manifestations of COVID-19 children are milder than those of influenza A children under 5 years.

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The laboratory tests of COVID-19 children are milder than those of influenza A children under 5 years.

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Imaging results more commonly presented as ground-glass opacities in COVID-19 patients.

Background

Since the outbreak of Coronavirus Disease 2019 (COVID-19) in Wuhan, considerable attention has been paid to its epidemiology and clinical characteristics in children. However, it is also crucial for clinicians to differentiate COVID-19 from other respiratory infectious diseases, such as influenza viruses.

Methods

This was a retrospective study. Two groups of COVID-19 patients (n = 57) and influenza A patients (n = 59) were enrolled. We analyzed and compared their clinical manifestations, imaging characteristics and treatments.

Results

The proportions of cough (70.2%), fever (54.4%) and gastrointestinal symptoms (14.1%) in COVID-19 patients were lower than those of influenza A patients (98.3%, P < 0.001; 84.7%, P < 0.001; and 35.6%, P = 0.007; respectively). In addition, COVID-19 patients showed significantly lower levels of leukocytes (7.87 vs. 9.89 × 10⁹ L^–1, P = 0.027), neutrophils (2.43 vs. 5.16 × 10⁹ L^–1, P < 0.001), C-reactive protein (CRP; 3.7 vs. 15.1 mg/L, P = 0.001) and procalcitonin (PCT; 0.09 vs. 0.68 mm/h, P < 0.001), while lymphocyte levels (4.58 vs. 3.56 × 109 L^–1; P = 0.006) were significantly higher compared with influenza A patients. In terms of CT imaging, ground-glass opacification in chest CT was more common in COVID-19 patients than in influenza A patients (42.1% vs. 15%, P = 0.032). In contrast, consolidation was more common in influenza A patients (25%) than in COVID-19 patients (5.2%, P = 0.025).

Conclusion

The clinical manifestations and laboratory tests of COVID-19 children are milder than those of influenza A children under 5 years. Additionally, imaging results more commonly presented as ground-glass opacities in COVID-19 patients.

Transient depression of myocardial function after influenza virus infection: A study of echocardiographic tissue imaging

Background

Influenza virus infection (IVI) was reported to be associated with minor cardiac changes, mostly those detected on electrocardiogram with and without elevated blood markers of myocardial injury; however, the characteristics of myocardial involvement in association with IVI are poorly understood. This study used echocardiographic tissue imaging (tissue Doppler, strain, and strain rate) to evaluate changes in left atrial (LA) and left ventricular (LV) myocardial function after IVI.

Methods and results

We examined 20 adult individuals (mean age, 43 years) at 2 and 4 weeks after diagnosis of IVI. For myocardial functional variables, we obtained LV global longitudinal strain (GLS), LV early diastolic strain rate (e'sr), LA strain, and LA stiffness (E/e’/LA strain), in addition to data on tissue Doppler (s’, e’, and a’) and myocardial performance index. Blood markers of myocardial injury were also examined. During follow-up, there were no significant changes in global chamber function such as LV ejection fraction, E/e’, and LA volume. However, significant changes in myocardial function were observed, namely, in s’ (8.0 ± 1.6 cm/s to 9.3 ± 1.5 cm/s; p = 0.01), e’ (10.2 ± 2.8 cm/s to 11.4 ± 3.0 cm/s; p < 0.001), e’sr (1.43 ± 0.44 1/s to 1.59 ± 0.43 1/s; p = 0.005), and LA strain (35 ± 8% to 40 ± 12%; p = 0.025), and the myocardial performance index (0.52 ± 0.20 to 0.38 ± 0.09; p = 0.009), but not in a’, LA stiffness, or GLS. Cardiac troponin T and creatinine kinase isoenzyme MB were not elevated significantly at any examination.

Conclusions

Myocardial dysfunction during IVI recovery appeared to be transient particularly in the absence of myocardial injury. Echocardiographic tissue imaging may be useful to detect subclinical cardiac changes in association with IVI.

Rescue of four pediatric patients with severe influenza A (H3N2) in Weifang, China

In this report, we summarize our experience of rescuing four children with severe type A H3N2 influenza from January to February 2017 in Weifang People's Hospital, Shandong Province, China for reference in clinical treatment. Two boys and two girls, ranging in age from 3 months to 6 years, with fever, cough, and asthma, were admitted to the pediatric intensive care unit. All children had severe pulmonary infection with respiratory distress. Three children had myocardial damage, two had liver damage, and one had encephalitis. One child had a history of bronchial asthma and one had severe spinal muscular atrophy. After all four children were admitted to the pediatric intensive care unit, they were provided active and effective organ function support and ventilator-assisted respiration. They were treated with gamma globulin, methylprednisolone, and antibiotics. Three children were treated with anti-influenza drugs and recovered from influenza; one child died even before antiviral treatment intervention on the first day. Definite diagnosis of the cases was through clinical manifestations, supplemented by laboratory tests, such as influenza virus H3N2 rapid antigen detection and nucleic acid detection. Early antiviral therapy, high-dose glucocorticoids and immunoglobulins, and systemic comprehensive rescue might be important for rescuing children with severe influenza A (H3N2).

Focal Encephalitis, Meningitis, and Acute Respiratory Distress Syndrome Associated with Influenza A Infection

OBJECTIVE

To present a case of influenza A infection complicated with focal encephalitis, meningitis, and acute respiratory distress syndrome.

CLINICAL PRESENTATION AND INTERVENTION

A 35-year-old woman presented with fever, headache, cough, and body aches. Seizures, altered consciousness, and dyspnea occurred later. A nasopharyngeal swab revealed a positive reaction for the influenza A antigen. Magnetic resonance imaging scans showed a T2 prolongation in the left frontoparietal subcortical white matter, which was consistent with focal encephalitis. She recovered after treatment with oseltamivir and antibiotics.

CONCLUSION

This case report highlights focal encephalitis with concomitant pulmonary complications after influenza A infection.

CT findings in viral lower respiratory tract infections caused by parainfluenza virus, influenza virus and respiratory syncytial virus

Viral lower respiratory tract infections (LRTIs) can present with a variety of computed tomography (CT) findings. However, identifying the contribution of a particular virus to CT findings is challenging due to concomitant infections and the limited data on the CT findings in viral LRTIs. We therefore investigate the CT findings in different pure viral LRTIs.All patients who underwent bronchoalveolar lavage (BAL) and were diagnosed with LRTIs caused by parainfluenza virus (PIV), influenza virus, or respiratory syncytial virus (RSV) between 1998 and 2014 were enrolled in a tertiary hospital in Seoul, South Korea. A pure viral LRTI was defined as a positive viral culture from BAL without any positive evidence from respiratory or blood cultures, or from polymerase chain reaction (PCR), or from serologic tests for bacteria, fungi, mycobacteria, or other viruses.CT images of 40 patients with viral LRTIs were analyzed: 14 with PIV, 14 with influenza virus, and 12 with RSV. Patch consolidation (≥1 cm or more than 1 segmental level) was found only in PIV (29%) (P = 0.03), by which CT findings caused by PIV could resemble those seen in bacterial LRTIs. Ground-glass opacities were seen in all cases of influenza virus and were more frequent than in PIV (71%) and RSV (67%) (P = 0.05). Bronchial wall thickening was more common in influenza virus (71%) and RSV (67%) LRTIs than PIV LRTIs (21%) (P = 0.02). With respect to anatomical distribution, PIV infections generally affected the lower lobes (69%), while influenza virus mostly caused diffuse changes throughout the lungs (57%), and RSV frequently formed localized patterns in the upper and mid lobes (44%).The CT findings in LRTIs of PIV, influenza virus, and RSV can be distinguished by certain characteristics. These differences could be useful for early differentiation of these viral LRTIs, and empirical use of appropriate antiviral agents.

Clinical and Radiographic Comparison of Influenza Virus-associated Pneumonia among Three Viral Subtypes

OBJECTIVE

Presently, the predominant subtypes of influenza viruses in the world, except for those in local epidemics, include influenza pandemic H1N1 2009 (pH1N1), H3N2, and B viruses. There are few reports on the differences in the clinical features, radiographic findings, treatment, and outcomes of influenza virus-associated pneumonia among these three viral subtypes. The purpose of this study was to investigate whether the clinical features, radiographic findings, treatment, and outcomes differ among the viral subtypes.

METHODS

We retrospectively analyzed 96 patients with influenza virus-associated pneumonia whose viral subtypes were clarified.

RESULTS

Patients with pH1N1 virus-associated pneumonia tended to be young. The frequency of primary viral pneumonia differed among the virus-associated pneumonia subtypes (pH1N1, 80%; H3N2, 26.5%; and B, 31%). Patients with pH1N1 virus-associated pneumonia more frequently showed bilateral ground-glass opacities (GGOs), which affected more lobes than in patients with H3N2 and B virus-associated pneumonia. However, patients with H3N2 virus-associated pneumonia showed a higher frequency of consolidation and diffuse bronchial wall thickening than did the patients with pH1N1 virus-associated pneumonia. The severity and mortality did not differ among the three pneumonia subtypes.

CONCLUSION

In the patients who developed influenza virus-associated pneumonia, those with pH1N1 virus-associated pneumonia frequently developed primary viral pneumonia resulting in bilateral and broad areas of GGOs on imaging, whereas patients with H3N2 virus-associated pneumonia frequently showed consolidation and diffuse bronchial wall thickening on pulmonary imaging.

Persistence of lymphocytopenia with CT abnormalities among patients with critical H7N9 swine-origin influenza A virus infection

PURPOSE

H7N9 is an emerging pathogen with associated morbidity and mortality, and a broader understanding of the chest radiographic characteristics associated with human H7N9 infections is needed. This study was performed to determine the time course of recovery from lymphocytopenia and resolution of pneumonitis of critical H7N9 infection patients.

MATERIALS AND METHODS

We performed chest X-ray and computed tomography (CT) for patients with H7N9 influenza. Lesion patterns, distributions, and changes at follow-up chest X-ray and/or CT were investigated. The time to progression on chest CT image, and the time to resolution of the chest CT findings were assessed.

RESULTS

Lymphocytopenia was a common laboratory test abnormality. The most common CT findings were lobar consolidation with air bronchogram and ground-glass opacities. For 7 recovering patients, the time to resolution of the chest CT findings was 10-90 days. Fibrosis and traction bronchiectasis were the main features on the CT scans of recovering patients. Interestingly, the time to recovery from lymphopenia was highly consistent with time to resolution of the chest CT findings.

CONCLUSIONS

We have shown the presence of radiographic abnormalities among H7N9 patients. Monitoring of the variation of lymphocytes for H7N9 patients has important clinical significance, especially for prediction of the resolution of pneumonitis.

Comparison of chest-CT findings of Influenza virus-associated pneumonia in immunocompetent vs. immunocompromised patients

PURPOSE

To retrospectively compare CT-patterns of pulmonary infiltration caused by different Influenza virus types and subtypes in immunocompetent and immunocompromised patients for possible discrimination.

MATERIALS AND METHODS

Retrospective database search at our institution yielded 237 patients who were tested positive for Influenza virus type A or type B by bronchoalveolar lavage between January 2009 and April 2014. Fifty-six of these patients (female 26; male 30; median age 55.8 y, range 17-86 y; SD ± 14.4 y) underwent chest-HRCT due to a more severe clinical course of pulmonary infection. We registered all CT-findings compatible with pulmonary infection classifying them as airway predominant (tree-in-bud, centrilobular nodules, bronchial wall thickening ± peribronchial ground-glass opacity and consolidation) vs. interstitial-parenchymal predominant (bilateral, symmetrical GGO, consolidation, crazy paving and/or interlobular septal thickening). Twenty-six patients (46.4%) had follow-up CT-studies (0.78 mean, SD ± 5.8 scans).

RESULTS

Thirty-six patients were immunocompromised (group I) whereas 20 patients were immunocompetent (group II). An airway-centric pattern of infection was found in 15 patients (group I) and 14 patients (group II) whereas an interstitial-parenchymal predominant pattern was found in 14 patients (group I) and 2 patients (group II). Eleven patients had a mixed pattern with no clear assignment to one group. At FU, 12 patients from group I and 3 from group II showed transitional infiltration patterns: in 10 patients from interstitial-parenchymal into airway predominant pattern and in five patients from airway predominant into interstitial-parenchymal. No significant differences in the pattern of pulmonary infection were found between different types and subtypes of Influenza viruses.

CONCLUSION

Patterns of pulmonary infiltration caused by Influenza viruses do not significantly differ between immunocompetent and immunocompromised patients or between different types and subtypes of Influenza virus. One possible explanation for this could be the temporarily interchangeable character of pulmonary infiltration in this infection.

Human infection with a novel avian-origin influenza A (H7N9) virus: serial chest radiographic and CT findings

BACKGROUND

Rapidly progressive pneumonia infection with H7N9 virus is a novel disease, and limited information is available concerning serial chest radiographic and computed tomography (CT) findings. The aim of this study was to evaluate the changes in serial radiologic findings in patients with H7N9 pneumonia.

METHODS

The two institutional ethics review boards approved this retrospective study. This study included 10 patients with H7N9 pneumonia. All patients underwent chest radiologic examinations at different time points. Serial radiologic images were systematically analyzed.

RESULTS

All patients showed abnormal results on initial chest radiography and CT. The initial radiographic abnormalities were unilateral (n = 9) and bilateral (n = 1), including ground-glass opacities (GGOs) (n = 5) and consolidation (n = 5). The initial CT findings consisted of unilateral (n = 6) and bilateral (n = 4), including consolidation (n = 10), GGOs (n = 10), reticular opacities (n = 2), and pleural effusion (n = 3). Follow-up radiologic findings showed rapid development of consolidation or GGOs within two weeks after illness onset. Pneumomediastinum with secondary subcutaneous emphysema and pneumothorax were noted in two patients. Follow-up high resolution computed tomography (HRCT) after two weeks showed slow improvement in both size and opacity of the lesions. On HRCT after discharge, patients had substantial residual lesions such as irregular linear opacities, reticular opacities, parenchymal bands, traction bronchiectasis, and cystic lesions.

CONCLUSIONS

The most common radiologic findings at presentation are multifocal or diffuse areas of consolidation and GGOs in H7N9 pneumonia. HRCT in sequence can show more changes in rapid progression of disease and a slow decrease of both size and opacity of the lesions plays an important role in the evaluation of H7N9 pneumonia.

Bedside chest radiography of novel influenza A (H7N9) virus infections and follow-up findings after short-time treatment

BACKGROUND

Influenza A (H7N9) virus infections were first observed in China in March 2013. This type virus can cause severe illness and deaths, the situation raises many urgent questions and global public health concerns. Our purpose was to investigate bedside chest radiography findings for patients with novel influenza A (H7N9) virus infections and the followup appearances after short-time treatment.

METHODS

Eight hospitalized patients infected with the novel influenza A (H7N9) virus were included in our study. All of the patients underwent bedside chest radiography after admission, and all had follow-up bedside chest radiography during their first ten days, using AXIOM Aristos MX and/or AMX-IV portable X-ray units. The exposure dose was generally 90 kV and 5 mAs, and was slightly adjusted according to the weight of the patients. The initial radiography data were evaluated for radiological patterns (ground glass opacity, consolidation, and reticulation), distribution type (focal, multifocal, and diffuse), lung zones involved, and appearance at follow-up while the patients underwent therapy.

RESULTS

All patients presented with bilateral multiple lung involvement. Two patients had bilateral diffuse lesions, three patients had unilateral diffuse lesions of the right lobe with multifocal lesions of the left lobe, and the remaining three had bilateral multifocal lung lesions. The lesions were present throughout bilateral lung zones in three patients, the whole right lung zone in three patients with additional involvement in the left middle and/or lower lung zone(s), both lower and middle lung zones in one patient, and the right middle and lower in combination with the left lower lung zones in one patient. The most common abnormal radiographic patterns were ground glass opacity (8/8), and consolidation (8/8). In three cases examined by CT we also found the pattern of reticulation in combination with CT images. Four patients had bilateral and four had unilateral pleural effusion. After a short period of treatment the pneumonia in one patient had significantly improved and three cases demonstrated disease progression. In four cases the severity of the pneumonia fluctuated.

CONCLUSIONS

In patients with influenza A (H7N9) virus infection, the distribution of the lung lesions are extensive, and the disease usually involves both lung zones. The most common imaging findings are a mixture of ground glass opacity and consolidation. Pleural effusion is common. Most cases have a poor short-time treatment response, and seem to have either rapid progressive radiographic deterioration or fluctuating radiographic changes. Chest radiography is helpful for evaluating patients with severe clinical symptoms and for follow-up evaluation.

Comparison of demographic, clinical, radiological characteristics and comorbidities in mechanically ventilated and nonventilated, adult patients admitted in ICU with confirmed diagnosis of influenza A (H1N1)

INTRODUCTION

Influenza A(H1N1) infection affected Indian population in 2009. Patients needed ICU admission and monitoring. Simple demographic, clinical and radiological variables are described in this article in mechanically ventilated and nonventilated patients.

OBJECTIVES

To describe and correlate demographic, clinical, radiographic characteristics and comorbidities in mechanically ventilated and nonventilated, adult patients admitted in ICU with confirmed diagnosis of Influenza A(H1N1) infection.

MATERIAL AND METHODS

Retrospective study of records of 100 RT-PCR confirmed patients with Influenza A (H1N1) infection from August 2009 to March 2010 was done. Each patient underwent an evaluation to determine demographic, clinical and radiographic features, comorbidities, mechanical ventilator required or not.

RESULTS

35 Patients required mechanical ventilation. 27 required IMV, 4 required NIMV while 4 patients initially were put on NIMV required IMV subsequently. 19 (40.42%) female patients required mechanical ventilator. Mean age of mechanically ventilated patients was 33 years, mean duration of illness was 7.9 days, mean duration of hospital stay was 6.8 days. 07 (20.00%) patients with pregnancy, 05 (14.29%) with DM, 05 (14.29%) with HT, 04/11.43%) with obesity required mechanical ventilator. 97.14% patients with fever, 88.54% with breathlessness, 11.43% with haemoptysis, 31.42% patients with throat pain required mechanical ventilator. However except Tachypnoea (p <0.01) no other symptom was statistically significant for mechanical ventilation 33(36.26%) patients with abnormal X ray,16 (80.00%) patients with right sided, 09(60.00%) patients with left sided and 40(71.43%) patients with bilateral disease required mechanical ventilator, right sided (p < 0.01) and bilateral (p <0.01) disease is statistically significant for requirement of mechanical ventilator. 33(47.14%) patients with lower zone involvement, 44 (67.70%) patients with middle zone and 23 (47.92%) patients with upper zone involvement required mechanical ventilator. Upper zone disease (p < 0.01) and middle zone disease (p < 0.01) is statistically significant for requirement of ventilator. 23 (47.92%) patients with right upper zone, 29 (42.64%) patients with right middle zone, 29 (46.77%) with left middle zone, 32 (42.67%) with right lower zone involvement required mechanical ventilator. RUZ (p < 0.01), RMZ (p < 0.01), LMZ (p < 0.001) and RLZ (p < 0.01) involvement had statistical significance for requirement of mechanical ventilator. 20 (33.89%) patients with patchy consolidation, 08 (36.36%) patients with reticulonodular and 05 (50.00%) patients with nodular pattern required mechanical ventilator however none of the pattern is statistically significant for mechanical ventilator. 08 (72.72%) patients with 6 zone involvement, 05 (50.00%) patients with single zone, 08 (40.00%)patients with 4 zone and 06 (33.33%) patients with 3 zone involvement required mechanical ventilator,however none was statistically significant for mechanical ventilator. All four patients requiring NIMV survived, while 28 died out of 31 on IMV.

CONCLUSIONS

Mechanical ventilation requirement was more in females, in presence of comorbidities like pregnancy, DM, HT, in presence of tachypnoea, in presence of bilateral disease and in presence of middle zone and right upper zone disease and with multiple zone disease. All patients with heart involvement required mechanical ventilator. If there is radiological finding of right upper zone involvement, then, there is more probability that these patients require mechanical ventilator for case management. Similarly, RMZ, LMZ and RLZ and cardiomegaly if shown in X-ray, the necessity of ventilator management is more.

A detailed epidemiological and clinical description of 6 human cases of avian-origin influenza A (H7N9) virus infection in Shanghai

BACKGROUND

The world's first reported patient infected with avian influenza H7N9 was treated at the Fifth People's Hospital of Shanghai. Shortly thereafter, several other cases emerged in the local area. Here, we describe the detailed epidemiological and clinical data of 6 cases of avian influenza H7N9.

METHODS AND FINDINGS

We analyzed the epidemiologic and clinical data from clustered patients infected with H7N9 in the Minhang District of Shanghai during a 2-week period. Of the 6 patients, 2 were from a single family. In addition, 3 patients had a history of contact with poultry; however, all 6 patients lived in the proximity of 2 food markets where the H7N9 virus was detected in chickens and pigeons. The main symptoms were fever, cough, and hemoptysis. At onset, a decreased lymphocyte count and elevated creatine kinase, lactate dehydrogenase, procalcitonin, and C-reactive protein levels were observed. As the disease progressed, most patients developed dyspnea and hypoxemia. Imaging studies revealed lung consolidation and multiple ground-glass opacities in the early stage, rapidly extending bilaterally. All patients were treated with oseltamivir tablets beginning on days 3-8 after onset. The main complications were as follows: acute respiratory distress syndrome (ARDS; 83.3%), secondary bacterial infection (66.7%), pleural effusion (50%), left ventricular failure (33.3%), neuropsychiatric symptoms (33.3%), and rhabdomyolysis (16.7%). Of the 6 patients, 4 died of ARDS, with 2 patients recovering from the infection.

CONCLUSIONS

An outbreak of H7N9 infection occurred in the Minhang District of Shanghai that easily progressed to acute respiratory distress syndrome. Two cases showed family aggregation, which led us to identify the H7N9 virus and indicated that human transmission may be involved in the spread of this infection.

Clinicoradiologic correlation in adult patients diagnosed with novel influenza A (H1N1)

BACKGROUND

Influenza A(H1N1) infection affected Indian population in 2009. Patients needed ICU admission and monitoring.

OBJECTIVES

To describe and correlate clinical and radiographic features of Influenza A(H1N1) infection in patients hospitalised in Intensive care unit.

MATERIAL AND METHODS

Retrospective study of records of 100 RT-PCR confirmed patients with Influenza A(H1N1) infection from August 2009 to March 2010 was done. Each patient underwent an evaluation to determine clinical and radiographic features.

RESULTS

Mean age of the patients was 33.43 years (+/- 12.152) with maximum patients between 18-40 years, with 53% males and 43% females. Cough (96%), Fever (95%), breathlessness (83%), throat pain (34%), crepitations (69%), Tachypnoea (59%)were the prominent symptoms and signs. 61% (n = 63) had comorbid condition like pregnancy (n = 13,20.63%), Diabetes Mellitus (DM) (n = 12,19.05%), HT (n = 11,17.60%), Obesity (n = 10, 15.87%) and Rheumatic Valvular Heart Disease (RVHD) (n = 6,09.52%). Chest X ray was abnormal in 91% patients and normal in 09% pts. Bilateral findings were seen in 61.53% cases. Most common zones affected were lower zones (77.46%), then middle zones (71.42%), followed by upper zones (42.7%). Most common patterns were consolidation (64.83%), reticulonodular (24.17%) and nodular (10.98%). 27.47% had two, 21.97% had four, 19.78% had three,12.08% had six, 7.69% had five and 10.98% had single zone involvement. Fever, cough and tachypnoea were present in all 100% pts with nodular pattern while crepitations were observed in 79.66% cases of consolidation. Patchy consolidation was seen in comorbidities like pregnancy (n = 10) and obesity (n = 06), while reticulonodular pattern was observed in hypertensive patients (n = 06). Maximum number of deaths were between 21 and 30 years of age (60.71%). Total number of deaths were 28 with 60.71% (n = 17) deaths between 21 and 30 years of age. Deaths were more in presence of comorbidities like Pregnancy (n = 5, 17.85%), Hypertension (n = 4,14.28%), Diabetes (n = 3 10.21%) and RVHD (n = 3,10.71%), in presence of RLZ involvement (92.85%), RMZ (89.28%), LMZ (85.21%) and RUZ involvement (71.42%), with consolidation pattern (57.14%) followed by reticulonodular pattern (21.42%) and in presence of six zone involvement (36.37%) followed by four zone (35%) and then by three(33%) and two (32%) zone involvement. Mean duration of hospital stay was 9.1 days. 23% patients stayed for less than 5 days, 41% stayed between 9 and 14 days while only 7% required to stay for more than 15 days. 37% pts showed normal Xray at the time of discharge or death. 38% patients showed persistence of radiological lesion at discharge or death.

CONCLUSIONS

Young to middle age patients were commonly affected. Common comorbidities were Pregnancy, Diabetes, Hypertension, and Obesity and patients had fever, cough, breathlessness, tachypnoea, crepitations as common clinical features. Radiologically it was multizonal, bilateral disease with predominant lower zone involvement and common patterns were consolidation followed by reticulonodular and nodular. Patchy consolidation was more common in pregnancy and obesity while reticulonodular pattern was more in hypertensive patients. Fever, cough and tachypnoea were present in all 100% pts with nodular pattern. Crepitations were common in pts with consolidation. Clinical recovery preceded radiological recovery. Young to middle aged individuals died more. Deaths were more in presence of comorbidities like Pregnancy, HT, DM and RVHD, also with RLZ, RMZ, LMZ involvement and with consolidation pattern and with six zone involvement.

Clinical and radiological characteristics of 2009 H1N1 influenza associated pneumonia in young male adults

PURPOSE

Pneumonia was an important cause of death in 2009 H1N1 influenza pandemic (pH1N1). Clinical characteristics of pH1N1 have been described well, but discriminative characteristics suggesting pH1N1 infection in pneumonia patients are not evident today. We evaluated differences between clinical and radiologic characteristics for those associated and not associated with pH1N1 influenza during the pandemic period.

MATERIALS AND METHODS

We reviewed all patients with pneumonia who visited the Armed Forces Capital Hospital between July 2009 and February 2010. During this period, all pneumonia patients were tested for pH1N1 by reverse transcription-polymerase chain reaction (RT-PCR) using nasopharyngeal specimens.

RESULTS

In total, 98 patients with pneumonia were enrolled. Their median age was 20 years and all patients were males. Forty-nine (50%) of patients had pH1N1 infection and the others (50%) had negative results in pH1N1 RT-PCR. Patients with pH1N1 infection complained of dyspnea more commonly (83.3% vs. 29.0%; p<0.001), had higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores [5 (range, 0-12) vs. 3 (range, 0-11); p<0.01], fewer days of prehospital illness [2 (range, 0-10) vs. 4 (range, 0-14); p=0.001], and a higher chance of bilateral infiltrates on chest X-ray (CXR) (67.3% vs. 14.3%; p<0.001) and ground-glass opacity (GGO) lesions on computed tomography (CT; 48.9% vs. 22.0%; p<0.001) than patients without pH1N1 infection.

CONCLUSION

Dyspnea, bilateral infiltrates on CXR, and GGO on CT were dominant features in pH1N1-associated pneumonia. Understanding these characteristics can help selection of patients who require prompt antiviral therapy.

Clinical characteristics and outcomes in hospitalized patients with respiratory viral co-infection during the 2009 H1N1 influenza pandemic

Background

The clinical consequences of co-infection with two or more respiratory viruses are poorly understood. We sought to determine if co-infection with pandemic 2009–2010 influenza A H1N1 (pH1N1) and another respiratory virus was associated with worse clinical outcomes.

Methods

A retrospective cohort study was performed of all hospitalized patients with a positive respiratory viral panel (RVP) for two or more viruses within 72 hours of admission at our institution from October 2009 to December 2009. We compared patients infected with one respiratory virus to those with respiratory viral co-infection.

Results

We identified 617 inpatients with a positive RVP sample with a single virus and 49 inpatients with a positive RVP sample for two viruses (i.e. co-infection). Co-infected patients were significantly younger, more often had fever/chills, tachypnea, and they more often demonstrated interstitial opacities suggestive of viral pneumonia on the presenting chest radiograph (OR 7.5, 95% CI 3.4–16.5). The likelihood of death, length of stay, and requirement for intensive care unit level of care were similar in both groups, but patients with any respiratory virus co-infection were more likely to experience complications, particularly treatment for a secondary bacterial pneumonia (OR 6.8, 95% CI 3.3–14.2). Patients co-infected with pH1N1 and another respiratory virus were more likely to present with chest radiograph changes suggestive of a viral pneumonia, compared to mono-infection with pH1N1 (OR 16.9, 95% CI 4.5–62.7). By logistic regression using mono-infection with non-PH1N1 viruses as the reference group, co-infection with pH1N1 was the strongest independent predictor of treatment for a secondary bacterial pneumonia (OR 17.8, 95% CI 6.7–47.1).

Conclusion

Patients with viral co-infection, particularly with pH1N1, were more likely to have chest radiograph features compatible with a viral pneumonia and complications during their hospital course, particularly treatment for secondary bacterial pneumonia. Despite this, co-infection was not associated with ICU admission.

Analysis of the clinical characteristics and treatment of two patients with avian influenza virus (H7N9)

Avian influenza is one of the most dangerous contagions in poultry worldwide, and avian influenza A viruses are the major pathogens responsible. Outbreaks of H7N9, a strain of the avian influenza A virus H7 subtype, have increasingly been reported in several countries since 2007. This spring, H7N9 broke out in China and has thus far caused 24 cases of infection and 7 deaths. Recently, we treated two patients with H7N9 infection. The infection was characterized by respiratory symptoms, fever, rapid progression, and significant hypoxemia. Laboratory tests showed a low level or decrease in leukocytes, a drop in blood platelets, and an increase in myocardial enzymes and aspartate aminotransferase. Oseltamivir, anti-infective drugs, and immunoglobulin were administered. Supplemental oxygen or non-invasive mechanical ventilation helped to relieve symptoms. This report provides information on the clinical characteristics and treatment of two Chinese patients with H7N9.

Hamman-Rich syndrome revisited: how to avoid misdiagnosis

Please cite this paper as: Fujita et al. (2012) Hamman‐Rich syndrome revisited: How to avoid misdiagnosis. Influenza and Other Respiratory Viruses. DOI: 10.1111/j.1750‐2659.2012.00353.x.

Severe hypothalamopituitary dysfunction accompanied by influenza-associated encephalopathy: report of two pediatric cases

Severe influenza infection may lead to neurological damage, such as encephalopathy. This may, in turn, cause acquired hypothalamopituitary dysfunction, which can result in severe morbidity and even death. We herein report two pediatric patients who developed influenza-associated hypopituitarism and were subsequently diagnosed with encephalopathy. They were diagnosed with acute necrotizing encephalopathy and postresuscitation encephalopathy, respectively. Both showed evidence of endocrine dysfunction, and hormone replacement therapy of adrenal, thyroid, and antidiuretic hormones are resulting in continued cardiac activity and resulted in prolonged survival. Screening for endocrine function is important in patients with severe central nervous system dysfunction.

Prolonged period of acute bronchitis with late progression to acute respiratory distress syndrome as possible result of influenza A (H1N1) virus infection

Young adults with underlying medical conditions who are infected with the H1N1 virus are at risk of quickly progressing from mild upper airways infection to severe ARDS within 4 to 5 days after the onset of the illness. Here, we report the case of a 46-year-old morbidly obese and diabetic woman infected with the H1N1 virus who developed acute bronchitis that lasted for 4 weeks and then progressed to ARDS. We discuss the month-long persistence of the H1N1 viral bronchitis and its late progression to ARDS which may reflect prolonged viral activity. Such a prolonged, rather than quick, course of deterioration can cause clinicians to misdiagnose the etiology of the ARDS and may cause the patient to receive a prolonged treatment with steroids to treat bronchitis symptoms. These steroids may cause increased viral replication and promote parenchymal involvement and the development of ARDS.

Hiding in plain sight: H1N1 influenza presenting with respiratory failure and normal chest radiography

Sepsis and respiratory failure are uncommon complications of infection with H1N1 influenza. In the majority of cases of H1N1-associated sepsis and respiratory failure found in the literature, evidence of pneumonia or the acute respiratory distress syndrome was seen on chest radiography. This case report describes the clinical characteristics of a patient who presented with septic shock and multi-system organ failure due to H1N1 influenza, but had normal chest radiography. Beyond describing a unique presentation of H1N1-related sepsis, this report highlights the need for clinicians to maintain a high index of suspicion for infection with H1N1 influenza in patients with sepsis and respiratory distress.

Clinical, laboratory, and radiologic characteristics of confirmed avian influenza (H5N1)

This was a cross sectional study to determine the clinical, laboratory and radiologic characteristics of confirmed avian influenza (AI) (H5N1) infection among children and adults. This study was conducted at Sulianti Saroso Infectious Diseases Hospital (SS-IDH), Jakarta among subjects confirmed to have AI infection hospitalized during September 2005 to August 2010. The proportion of confirmed AI patients was 33 out of 321 suspected and probable cases (10.2%). Of 26 subjects analyzed (7 subjects was excluded due to loss of or incomplete medical records), the median ages were 7 years and 25 years in children and adults, respectively (range 1 - 39 years). Prominent clinical features were respiratory symptoms [productive cough (13/13 children; 12/13 adults), dyspnea (12/13 children; 13/13 adults)], and fever (12/13 children; 12/13 adults). Leukopenia was found in 9 subjects in each group. Four children and 7 adults had lymphopenia, while thrombocytopenia was found in 7 children and 10 adults. Two children had an increased ALT, while most adults had an increased AST (10/13) and/or ALT (8/13). Bilateral infiltrates found in most subjects on chest x-ray who had clinical deterioration. Of the 3 children who survived out of 13 children with AI, they all had less severe clinical features and no central nervous system involvement, lymphopenia, thrombocytopenia, or increased creatinine level. None of the adults survived.

Critical influenza (H1N1) pneumonia: imaging manifestations and histopathological findings

BACKGROUND

The global outbreak of influenza A (H1N1) has led to the Ministry of Health of China listing it as one of the A-class infectious diseases. Pneumonia is the most serious complication of influenza A, commonly causing death. Populations are ordinarily susceptible to influenza A. This study aimed to investigate the imaging manifestation features of critical influenza A (H1N1) pneumonia and to improve its diagnostic techniques.

METHODS

A total of seven death cases from critical influenza A (H1N1) pneumonia were retrospectively analyzed on their imaging manifestations and autopsy data. Pulmonary CT scanning was performed for five cases, with one receiving additional chest X-ray and chest CT scanning, and chest postero-anterior position X-ray examination was performed for other two. Autopsy was performed for five cases and postmortem examinations were performed for other two cases.

RESULTS

The seven cases of influenza A showed critical manifestations in 4 - 7 days after symptoms onset, with two having basic diseases of diabetes and one being pregnant. Extensive blurry high-density shadows of bilateral lungs were found in three cases, which were most obvious in middle and inferior parts of lungs. Pulmonary CT scanning revealed bilateral flaky parenchymal shadows in peripheral, dorsal and fundus segments of the middle-inferior parts of lungs, with one case of complicated pneumothorax, atelectasis and pleural effusion and another case of thin-walled cavity and dilated bronchi shadows in the superior parts of lungs.

CONCLUSIONS

Diagnostic imaging is an important assessing tool for critical influenza A (H1N1) pneumonia. The imaging manifestations are characteristic instead of being specific. The definitive diagnosis can be made in combination with clinical examinations and laboratory tests.

H1N1 pneumonia: our experience in 50 patients with a severe clinical course of novel swine-origin influenza A (H1N1) virus (S-OIV)

PURPOSE

The authors reviewed chest radiographs (CXR) and thin-section computed tomography (CT) findings of pulmonary complications in a selected population of 50 consecutive patients with severe novel swine-origin influenza A (H1N1) virus (S-OIV) pneumonia who were seen at the Subintensive Respiratory Unit (UTSIR) and at the Intensive Care Unit (ICU) at Monaldi Hospital, Naples, Italy.

MATERIALS AND METHODS

CXR and CT findings of 50 patients who fulfilled the World Health Organisation (WHO) criteria for S-OIV infection were reviewed by four radiologists. The final study group of 50 patients was divided into two subgroups on the basis of clinical course: group 1 consisted of 42 patients requiring noninvasive mechanical ventilation and admitted to the UTSIR; group 2 consisted of eight patients who required ICU admission and extracorporeal membrane oxygenation or advanced mechanical ventilation from October 2009 to December 2009. All patients underwent CXR and thin-section multidetector CT (MDCT) scan; the initial and follow-up radiographs and CT scans were evaluated for the presentation and follow-up pattern (consolidation, ground-glass opacities, nodules, reticulation), distribution and extent of abnormality.

RESULTS

All patients had radiological signs of pulmonary involvement. Ground-glass opacity and consolidation, which was mainly peripheral, was the most frequent finding. In three patients, we report for the first time in viral pneumonia the reversed halo sign. Lesion extent was related to aggressiveness of the illness. More often, both lungs were involved (82%). Thoracic comorbidity was present in 18% of patients; 22% of patients was obese, and in this group, the clinical course was more aggressive than in the others with the same lesion extent at imaging. Furthermore, superinfection led to worsening of the clinical conditions.

CONCLUSIONS

The most common CXR and CT findings in patients with S-OIV infection were unilateral or bilateral ground-glass opacities with or without associated focal or multifocal areas of consolidation. On MDCT, ground-glass opacities and areas of consolidation had a predominant peribronchovascular and subpleural distribution, resembling organising pneumonia; they progressed to bilateral extensive airspace disease in severely ill patients.

Early recognition of the 2009 pandemic influenza A (H1N1) pneumonia by chest ultrasound

INTRODUCTION

The clinical picture of the pandemic influenza A (H1N1)v ranges from a self-limiting afebrile infection to a rapidly progressive pneumonia. Prompt diagnosis and well-timed treatment are recommended. Chest radiography (CRx) often fails to detect the early interstitial stage. The aim of this study was to evaluate the role of bedside chest ultrasonography (US) in the early management of the 2009 influenza A (H1N1)v infection.

METHODS

98 patients who arrived in the Emergency Department complaining of influenza-like symptoms were enrolled in the study. Patients not displaying symptoms of acute respiratory distress were discharged without further investigations. Among patients with clinical suggestion of a community-acquired pneumonia, cases encountering other diagnoses or comorbidities were excluded from the study. Clinical history, laboratory tests, CRx, and computed tomography (CT) scan, if indicated, contributed to define the diagnosis of pneumonia in the remaining patients. Chest US was performed by an emergency physician, looking for presence of interstitial syndrome, alveolar consolidation, pleural line abnormalities, and pleural effusion, in 34 patients with a final diagnosis of pneumonia, in 16 having normal initial CRx, and in 33 without pneumonia, as controls.

RESULTS

Chest US was carried out without discomfort in all subjects, requiring a relatively short time (9 minutes; range, 7 to 13 minutes). An abnormal US pattern was detected in 32 of 34 patients with pneumonia (94.1%). A prevalent US pattern of interstitial syndrome was depicted in 15 of 16 patients with normal initial CRx, of whom 10 (62.5%) had a final diagnosis of viral (H1N1) pneumonia. Patients with pneumonia and abnormal initial CRx, of whom only four had a final diagnosis of viral (H1N1) pneumonia (22.2%; P<0.05), mainly displayed an US pattern of alveolar consolidation. Finally, a positive US pattern of interstitial syndrome was found in five of 33 controls (15.1%). False negatives were found in two (5.9%) of 34 cases, and false positives, in five (15.1%) of 33 cases, with sensitivity of 94.1%, specificity of 84.8%, positive predictive value of 86.5%, and negative predictive value of 93.3%.

CONCLUSIONS

Bedside chest US represents an effective tool for diagnosing pneumonia in the Emergency Department. It can accurately provide early-stage detection of patients with (H1N1)v pneumonia having an initial normal CRx. Its routine integration into their clinical management is proposed.

Chest computed tomography findings in severe influenza pneumonia occurring in neutropenic cancer patients

OBJECTIVE

To describe the chest computed tomography findings for severe influenza H1N1 infection in a series of hospitalized neutropenic cancer patients.

METHODS

We performed a retrospective systematic analysis of chest computed tomography scans for eight hospitalized patients with fever, neutropenia, and confirmed diagnoses of influenza H1N1. The clinical data had been prospectively collected.

RESULTS

Six of eight patients (75%) developed respiratory failure and required intensive care. Prolonged H1N1 shedding was observed in the three mechanically ventilated patients, and overall hospital mortality in our series was 25%. The most frequent computed tomography findings were ground-glass opacity (all patients), consolidation (7/8 cases), and airspace nodules (6/8 cases) that were frequently moderate or severe. Other parenchymal findings were not common. Five patients had features of pneumonia, two had computed tomography findings compatible with bronchitis and/or bronchiolitis, and one had tomographic signs of chronicity.

CONCLUSION

In this series of neutropenic patients with severe influenza H1N1 infection, chest computed tomography demonstrated mainly moderate or severe parenchymatous disease, but bronchiolitis was not a common feature. These findings associated with febrile neutropenia should elicit a diagnosis of severe viral infection.

Pneumonia induced by swine-origin influenza A (H1N1) infection: chest computed tomography findings in children

PURPOSE

The purpose of this study was to determine the features of chest computed tomography (CT) in children with swine-origin influenza A (H1N1) virus (S-OIV).

MATERIALS AND METHODS

The study population consisted of 16 children with laboratory-confirmed S-OIV infection (12 boys, 4 girls), with an age range of 5-10 years (mean 6.3 years). Pneumonia was suspected in these patients based on clinical features or confirmed by radiography. All subjects underwent CT for close evaluation of pneumonia, including characteristics, distribution, extent, and other findings such as pleural effusion, pneumothorax, and pneumomediastinum.

RESULTS

The predominant CT finding was consolidation plus ground-grass opacity (GGO) (11/16, 69%). The consolidation-dominant pattern was found in 10 of 16 (66%) patients, and 1 (6%) was GGO-dominant. One (6%) had only GGO. In all, 7 of the 16 patients had segmental or lobar consolidation. Abnormal opacities were primarily distributed in the central lung zone (8/16, 50%) and were multifocal (15/16, 94%). Four showed atelectasis (4/16, 25%). Pneumomediastinum was observed in 4 of 16 (25%). One patient had negative radiographic findings but was positive on CT.

CONCLUSION

Multifocal consolidation with central distribution is a common CT finding in children with S-OIV, but there are few GGO-dominant cases. Widespread consolidation (segmental or lobar) is also common.

Acute Respiratory Distress Syndrome as a presenting manifestation in young patients infected with H1N1 influenza virus

INTRODUCTION

The new strain of influenza A (H1N1) 2009, often referred to colloquially as "swine flu", which was first detected in April 2009, raised to a pandemic of which the impact was not completely predictable. As reported, numerous cases with severe respiratory failure were also seen among young previously healthy people.

PATIENTS

In the present study, we report eight cases of influenza A (H1N1) 2009 admitted to our medical intensive care with severe respiratory failure between November and December 2009 and in January 2011. All patients were older than 30 but younger than 50 years, had clinical and radiological evidence of an Acute Respiratory Distress Syndrome (ARDS) and needed invasive ventilatory support.

RESULTS

Six of the eight patients had no relevant underlying disease; one had a pre-existing idiopathic lung fibrosis and another had a chronic obstructive pulmonary disease (COPD), an abuse of alcohol and an adiposities grade 3. Four patients needed an extracorporeal membrane oxygenation (ECMO) due to severe respiratory failure with global respiratory insufficiency that could not be treated by conservative ventilatory support. The one patient with a pre-existing lung fibrosis died shortly after lung transplantation despite use of an extracorporeal membrane oxygenation. One other patient died due to a subarachnoidal bleeding under the anticoagulatory regime during ECMO therapy. The adipose COPD-patient died due to septic shock with multiple organ failure without possibility for ECMO support.

CONCLUSIONS

The clinical course of severe cases of influenza A (H1N1) 2009-infection is markedly different from the disease pattern seen during epidemics of seasonal influenza. Most of the patients admitted to our intensive care unit due to influenza A (H1N1) 2009 associated ARDS were previously healthy young people.

H1N1 influenza in an Irish population: patterns of chest radiograph abnormality in patients testing positive

The winter of 2010/2011 saw a second peak in the number of H1N1 cases detected in Ireland. The purpose of this study was to investigate the radiological characteristics of patients diagnosed during this period. A retrospective analysis of these cases was performed. Chest radiographs were classified as normal or abnormal. A total of 37 patients were included. Of these, 22 (59%) of chest radiographs were abnormal and 15 (41%) were normal. In the 7 paediatric patients, 4 (57%) had a perihilar distribution of disease, 2 (28%) had peripherally based disease with 1 (14%) having a mixed distribution. A series of radiographs was available for 9 patients, 6 of these showed a radiographic deterioration from the initial study. The majority of chest radiographs of patients with confirmed H1N1 infection will be abnormal. In children, disease is more likely to be perihilar in distribution. Chest radiography is an important initial investigation in patients with H1N1 infection and is useful to track progression of disease in the subset of patients requiring hospitalization for severe disease.

Severe influenza A (H1N1): the course of imaging findings

BACKGROUND

An outbreak of respiratory illness caused by a novel swine-origin influenza virus (influenza A/H1N1 2009) that began in Mexico was declared a global pandemic by the World Health Organization in June 2009. The pandemic affected many countries, including Israel.

OBJECTIVES

To compare the course of chest radiographic and computed tomography findings in patients who survived and those who died following admission to the intensive care unit (ICU) or intubation due to severe laboratory-confirmed swine-origin influenza A/H1N1 2009.

METHODS

We retrospectively reviewed the patient records (267 radiographs, 8 CTs) of 22 patients (10 males, 12 females) aged 3.5-66 years (median 34) with confirmed influenza A/ H1N1 2009, admitted to the ICU and/or intubated in five major Israeli medical centers during the period July-November 2009. We recorded demographic, clinical, and imaging findings--including pattern of opacification, extent, laterality, distribution, zone of findings, and presence/absence of nodular opacities--at initial radiography and during the course of disease, and compared the findings of survivors and non-survivors. Statistical significance was calculated using the Wilcoxon (continuous variables) and Fisher exact tests.

RESULTS

The most common findings on the initial chest radiography were airspace opacities, which were multifocal in 17 patients (77%) and bilateral in 16 (73%), and located in the lower or lower and middle lung zones in 19 patients (86%). Large airspace nodules with indistinct margins were seen in 8 patients (36%). Twelve patients survived, 10 died. Patients who died had multiple background illnesses and were significantly older than survivors (P = 0.006). Radiologic findings for the two groups were not significantly different.

CONCLUSION

Airspace opacities, often with nodular appearance, were the most common findings among patients with severe influenza A/H1N1 2009. The course of radiologic findings was similar in patients with severe influenza A/ H1N1 2009 who survived and those who died.

Distinguishing characteristics between pandemic 2009-2010 influenza A (H1N1) and other viruses in patients hospitalized with respiratory illness

Background

Differences in clinical presentation and outcomes among patients infected with pandemic 2009 influenza A H1N1 (pH1N1) compared to other respiratory viruses have not been fully elucidated.

Methodology/Principal Findings

A retrospective study was performed of all hospitalized patients at the peak of the pH1N1 season in whom a single respiratory virus was detected by a molecular assay targeting 18 viruses/subtypes (RVP, Luminex xTAG). Fifty-two percent (615/1192) of patients from October, 2009 to December, 2009 had a single respiratory virus (291 pH1N1; 207 rhinovirus; 45 RSV A/B; 37 parainfluenza; 27 adenovirus; 6 coronavirus; and 2 metapneumovirus). No seasonal influenza A or B was detected. Individuals with pH1N1, compared to other viruses, were more likely to present with fever (92% & 70%), cough (92% & 86%), sore throat (32% & 16%), nausea (31% & 8%), vomiting (39% & 30%), abdominal pain (14% & 7%), and a lower white blood count (8,500/L & 13,600/L, all p-values<0.05). In patients with cough and gastrointestinal complaints, the presence of subjective fever/chills independently raised the likelihood of pH1N1 (OR 10). Fifty-five percent (336/615) of our cohort received antibacterial agents, 63% (385/615) received oseltamivir, and 41% (252/615) received steroids. The mortality rate of our cohort was 1% (7/615) and was higher in individuals with pH1N1 compared to other viruses (2.1% & 0.3%, respectively; p = 0.04).

Conclusions/Significance

During the peak pandemic 2009–2010 influenza season in Rhode Island, nearly half of patients admitted with influenza-like symptoms had respiratory viruses other than influenza A. A high proportion of patients were treated with antibiotics and pH1N1 infection had higher mortality compared to other respiratory viruses.