Pediatric Parapneumonic Effusion/Pleural Empyema in Japan: A Nationwide Survey

Guidelines for the Management of Respiratory Infectious Diseases in Children in Japan 2022

The members of the Japanese Society for Pediatric Infectious Diseases and the Japanese Society of Pediatric Pulmonology have developed Guidelines for the Management of Respiratory Infectious Diseases in Children with the objective of facilitating appropriate diagnosis, treatment and prevention of respiratory infections in children. The first edition was published in 2004 and the fifth edition was published in 2022. The Guideline 2022 consists of 2 parts, clinical questions and commentary, and includes general respiratory infections and specific infections in children with underlying diseases and severe infections. This executive summary outlines the clinical questions in the Guidelines 2022, with reference to the Japanese Medical Information Distribution Service Manual. All recommendations are supported by a systematic search for relevant evidence and are followed by the strength of the recommendation and the quality of the evidence statements.

GCRV NS38 counteracts SVCV proliferation by intracellular antagonization during co-infection

Viral co-infection has been found in animals; however, the mechanisms of co-infection are unclear. The abundance and diversity of viruses in water make fish highly susceptible to co-infection. Here, we reported a co-infection in fish, which resulted in reduced host lethality and illustrated the intracellular molecular mechanism of viral co-infection. The spring viremia of carp virus (SVCV) is a highly lethal virus that infects Cyprinidae, such as zebrafish. The mortality of SVCV infection was significantly reduced when co-infected with the grass carp reovirus (GCRV). The severity of tissue damage and viral proliferation of SVCV was also reduced in co-infection with GCRV. The transcriptome bioinformatics analysis demonstrated that the effect on the host transcripts in response to SVCV infection was significantly reduced in co-infection. After excluding the extracellular interactions of these two viruses, the intracellular mechanisms were studied. We found that the GCRV NS38 remarkably decreased SVCV infection and viral proliferation. The interaction between GCRV NS38 and SVCV nucleoprotein (N) and phosphoprotein (P) proteins was identified, and NS38 downregulated both N and P proteins. Further analysis demonstrated that the N protein was degraded by NS38 indispensable of the autophagy receptor, sequestosome 1 (p62). Meanwhile, K63-linked ubiquitination of the P protein was reduced by NS38, leading to ubiquitinated degradation of the P protein. These results reveal that the intracellular viral protein interactions are a crucial mechanism of co-infection and influence the host pathology and expand our understanding in intracellular viral interactions co-infection.

Elevated Nitrite/Nitrate Ratio as a Potential Biomarker for the Differential Diagnosis of Pleural Effusions

Pleural effusions (PEs) are common in clinical practice and can be due to many different underlying diseases such as cancer, congestive heart failure, or pneumonia. An accurate differential diagnostic categorization is essential, as the treatment and prognosis of PEs largely depend on its cause. In this study, we tested the hypothesis that nitrite and nitrate concentrations in PEs are associated with the inflammation and infection conditions. We therefore measured the nitrite and nitrate levels in 143 PE samples using a sensitive liquid chromatography-tandem mass spectrometry method and investigated their diagnostic potential in differentiating PEs. The results showed that nitrite concentrations and nitrite/nitrate ratios were higher in exudates than in transudates (NO₂^-: 2.12 vs. 1.49 μM; NO₂^-/NO₃^-: 23.3 vs. 14.0). Both the nitrite concentrations and the nitrite/nitrate ratios were positively correlated with the three Light's criteria. Moreover, the receiver operating characteristic curve analysis revealed that the nitrite/nitrate ratio with an area under the curve of 0.71 could be a potential diagnostic biomarker in separating infectious PEs (IPEs) from other types of PEs. Taken together, the nitrite/nitrate ratio not only reflected the statuses of inflammation, but also the nitrate reduction by pathogenic bacteria infection in the pleural cavity. The nitrite/nitrate ratio could be a better biomarker in the differential diagnosis of PEs than the nitrite concentration alone.

Evaluation of the efficiency of the systemic immune-inflammation index in differentiating parapneumonic effusion from empyema

AIM

To evaluate the effectiveness of the systemic immune-inflammation index (SII) and other biomarkers in distinguishing parapneumonic effusion (PPE) and empyema.

METHODS

Patients who were thought to have pleural effusion secondary to pneumonia in the pediatric emergency department (PED) between 2004 and 2021 were retrospectively evaluated. The patients were divided into two groups as empyema and PPE. The efficacy of infection markers in predicting empyema was compared.

RESULTS

Fifty-nine patients (59.3% male) were included in the study. Forty-three (72.9%) patients were in the PPE and 16 (27.1%) were in the empyema group. Length of hospital stay and pleural fluid thickness measured with thoracic ultrasonography were significantly higher in the empyema group (p = 0.018 and p = 0.002, respectively). The mean SII was 1902.73 ± 1588.87 in PPE patients, while it was 6899.98 ± 6678 in empyema patients (p = 0.009). C-reactive protein (CRP), white blood cell (WBC) count, absolute neutrophil count (ANC), and neutrophil-lymphocyte ratio (NLR) ​​were significantly higher in the empyema group; absolute lymphocyte count (ALC) and lymphocyte-monocytes ratio (LMR) were significantly lower than the PPE group. When the best cut-off values of inflammation markers are determined according to the area under the curve, the highest odds ratios suggesting empyema were found in SII, LMR, CRP, and ANC, respectively.

CONCLUSION

Inflammation markers can be useful in predicting empyema. The best markers were found to be SII, LMR, CRP, and ANC. High SII is one of the practical diagnostic markers that can be used differentiate empyema from PPE in PED.