Clinical significance of pleural effusion in the new influenza A (H1N1) viral pneumonia in children and adolescent

Pleural macrophages translocate to the lung during infection to promote improved influenza outcomes

Seasonal influenza results in 3 to 5 million cases of severe disease and 250,000 to 500,000 deaths annually. Macrophages have been implicated in both the resolution and progression of the disease, but the drivers of these outcomes are poorly understood. We probed mouse lung transcriptomic datasets using the Digital Cell Quantifier algorithm to predict immune cell subsets that correlated with mild or severe influenza A virus (IAV) infection outcomes. We identified a unique lung macrophage population that transcriptionally resembled small serosal cavity macrophages and whose presence correlated with mild disease. Until now, the study of serosal macrophage translocation in the context of viral infections has been neglected. Here, we show that pleural macrophages (PMs) migrate from the pleural cavity to the lung after infection with IAV. We found that the depletion of PMs increased morbidity and pulmonary inflammation. There were increased proinflammatory cytokines in the pleural cavity and an influx of neutrophils within the lung. Our results show that PMs are recruited to the lung during IAV infection and contribute to recovery from influenza. This study expands our knowledge of PM plasticity and identifies a source of lung macrophages independent of monocyte recruitment and local proliferation.

Does CT help in reducing RT-PCR false negative rate for COVID-19?

BACKGROUND

Early detection is the key to contain the ongoing pandemic. The current gold standard to detect SARS CoV2 is RT-PCR. However, it has a high false negative rate and long turnaround time.

PURPOSE

In view of the high sensitivity of CT in detection of lower respiratory tract pathologies, a study of 2581 patients comparing RT-PCR status with CT findings was undertaken to see if it augments the diagnostic performance.

MATERIALS AND METHODS

A multi centre prospective study of consecutive cases was conducted. All CT studies suggestive of COVID 19 pneumonia were collated and evaluated independently by three Radiologists to confirm the imaging diagnosis of COVID-19 pneumonia. The RT-PCR values were retrospectively obtained, based on the RT-PCR values, CT studies were categorised into three subgroups, positive, negative and unknown. CT features from all three groups were compared to evaluate any communality or discordance.

RESULTS

Out of the 2581 patients with positive CT findings for COVID pneumonia, 825 were females and 1,756 were males in a wide age group of 28-90 years. Predominant CT features observed in all the subgroups were Ground glass densities 94.8%, in mixed distribution (peripheral and central) (59.12%), posterior segments in 92% and multilobar involvement in 70.9%. The CT features across the three subgroups were statistically significant with a P value <0.001.

CONCLUSION

There was a communality of CT findings regardless of RT-PCR status. In a pandemic setting ground glass densities in a subpleural, posterior and basal distribution are indicative of COVID 19. Thus CT chest in conjunction to RT PCR augments the diagnosis of COVID 19 pneumonia; utilization of CT chest may just be the missing link in closing this pandemic.

Herpes Simplex Virus Pneumonia in an Immunocompetent Child on Corticosteroids for Acute Wheezing

Herpes simplex virus (HSV) is rarely the cause of pneumonia in immunocompetent patients. We describe a previously healthy child, with no evidence of an immunodeficiency, who presented to the emergency department with severe pneumonia, wheezing, and pleural effusions with a history of orolabial HSV infection. On admission, he was started on antibiotics and systemic corticosteroids but continued to deteriorate. Oral lesions, blood, and pleural fluid tested positive for HSV, and improvement was achieved only after the addition of acyclovir and discontinuation of steroids. We suggest that steroids should be used with caution in patients presenting with lower respiratory tract symptoms and herpetic oral lesions.

Microbiological and chest X-ray studies on influenza B virus-associated pneumonia

Introduction

The signs and symptoms of influenza B are commonly ignored. Therefore, very few clinical reports are available. This study is an attempt to evaluate the clinical features and characteristics of influenza B virus-associated pneumonia patients.

Objective

The aim of this study is to investigate the microbiological and characteristics of influenza B virus-associated pneumonia patients.

Methodology

Patients with <16 years old with a clinical diagnosis of influenza B virus infection and who had chest radiography within 2 days were enrolled. A total of 49 patients were categorised as the pneumonia group by clinical symptoms and chest X-ray (CXR) findings, whereas 107 patients were categorised as the non-pneumonia group based on the laboratory data and normal CXR findings.

Results

The study observed that the age of the patients in the pneumonia group was significantly younger than the non-pneumonia group. The white blood cell (WBC) count of the pneumonia group was also higher. However, the haemoglobin (Hgb) level was lower in the pneumonia group. The C-reactive protein (CRP) level of the pneumonia group was also significantly high. The CXR findings revealed that 28.57% of patients had alveolar consolidation, 32.65% had interstitial infiltration and 40.82% had ground glass opacity.

Conclusions

High clinical suspicion is required to detect pneumonia in influenza B virus patients. Based on the CXR findings, the study also suggests that patients with pleural effusion and positive bacterial culture need more attention for the severity of clinical outcome. Moreover, critical care should be given to paediatric patients having higher WBC count, higher CRP level and lower Hgb. These parameters would be helpful to differentiate primary pneumonia from non-pneumonic influenza.

Clinical features of community acquired adenovirus pneumonia during the 2011 community outbreak in Southern Taiwan: role of host immune response

Background

Human adenovirus 7 (HAdV-7) was responsible for a significant number of fatalities during the 2011 community outbreak in Taiwan. The mechanisms underlying the pathogenesis of severe adenovirus infections in non-immunocompromised individuals remain unclear. Adenovirus pneumonia was associated with pleural effusion in a number of patients from the 2011 outbreak suggesting that similar to bacterial pneumonia, patients diagnosed with adenovirus pneumonia who have pleural effusion are more severely and systemically infected, and may have a more protracted disease course. We hypothesized that the host immunological response determines the severity of adenoviral infection.

Methods

This retrospective case series study included patients diagnosed with severe lower respiratory tract infections at the National Cheng Kung University Hospital in southern Taiwan between December 2010 and October 2011. The main inclusion criteria were 1) presence of multifocal patchy infiltrates, lobar consolidation or reticular interstitial opacities in chest X-rays, and 2) presence of adenovirus isolated from respiratory specimens. All patients had adenovirus isolated from respiratory specimens, and were negative for other viruses. Pleural effusion was confirmed in all patients using chest echography. Clinical features and laboratory data were compared in patients with (n = 12) and without (n = 15) parapneumonic effusion.

Results

Presence of parapneumonic effusion was significantly associated with a longer febrile duration, more complicated clinical management, and a greater risk of extrapulmonary involvement, notably hepatitis. Patients without pleural effusion had significantly higher numbers of WBCs, platelets, and absolute segment cell counts (ASCs) compared to patients with pleural effusion (all p < 0.05). Patients without pleural effusion had significantly higher counts of CD4+, CD8+, and CD20+ T cells (all p < 0.05) compared to patients with pleural effusion.

Conclusion

Our data indicated that presence of parapneumonic effusion in adenoviral pneumonia was associated with longer febrile duration, more complicated clinical management, a greater risk of hepatitis, and suppression of host cellular immunity. Further prospective, large-scale studies are needed to validate our results.

[Influenza and pregnancy]

Influenza is a respiratory disease caused by influenza viruses. The virus is responsible for pandemics by emergence of new viral strains, then for seasonal flu by antigenic drift. Seasonal flu is more frequent and severe in pregnant women, with increased risk of pneumonia and increased risk of hospitalization (but no increased death reported). Pandemic flu is more severe in pregnant women, with increased risk of pneumonia and increased mortality. Influenza vaccination is recommended for all women who are or will be pregnant (in any trimester) during influenza season. After closed contact with a flu case or in case of symptoms compatible with flu, early oseltamivir-based treatment (prophylactic in the first situation, curative in the latter one) is recommended, at any term of pregnancy. The occurrence of flu symptoms in a pregnant woman requires medical evaluation to confirm the diagnosis or identify any alternative infection requiring appropriate therapy like listeriosis, chorioamniotitis, pyelonephritis or viral primo-infection.

Influenza B virus-associated pneumonia in pediatric patients: clinical features, laboratory data, and chest X-ray findings

BACKGROUND

The clinical significance of influenza B is frequently overlooked, and reports on influenza B pneumonia in children are limited. Therefore, the clinical features of associated complications have rarely been reported. The aim of this study is to evaluate the clinical characteristics in pediatric patients with influenza B virus-associated pneumonia.

METHODS

From January 2009 to February 2012, 389 consecutive patients under 18 years old with influenza B virus infection were enrolled into the study. Thirty-four patients were defined as the pneumonia group by clinical symptoms and chest X-ray (CXR) findings, and 90 patients who had laboratory data and normal CXR findings were recruited to form the nonpneumonia group.

RESULTS

The age of the patients in the pneumonia group was significantly younger (median of 5.3 vs. 6.6 years). The white blood cell count (median of 7.5 vs. 5.7 × 10(9) cells/L) and C-reactive protein level (median of 21.1 vs. 5.7 mg/L) were higher, but the hemoglobin level was lower (median of 12.6 vs. 13.2 g/dL) in the pneumonia group. The CXR findings revealed that 29.4% of patients had alveolar consolidation, 32.4% had interstitial infiltration, and 38.2% had ground glass opacity. Two of four patients with pleural effusion had a positive bacteria culture, and both of them died.

CONCLUSION

Pneumonia should be considered in pediatric patients with influenza B virus infection presenting with younger age, higher white blood cell count, lower hemoglobin, and higher C-reactive protein level. The CXR findings were varied. Patients with pleural effusion and positive bacterial culture may have more severity of clinical outcome.