Plastic bronchitis associated with human bocavirus 1 infection in children.

BACKGROUND: Plastic bronchitis (PB) is a clinical-pathological syndrome characterized by the abnormal accumulation of endogenous substances in the bronchial airways, causing partial or complete obstruction and resulting in impaired lung ventilation. METHODS: In this retrospective analysis, we aim to summarize the clinical manifestations, imaging characteristics, diagnostic methods, and treatment approaches to enhance clinicians' ability to detect children who are infected with human bocavirus 1 (hBoV 1) and develop PB. RESULTS: In the period from January 2021 to January 2024, a total of six hBoV 1 infection children were diagnosed with PB through bronchoscopy. The onset of the condition was mainly concentrated between June and December. The detection methods used included metagenomic next-generation sequencing for pathogen identification (three cases) and respiratory pathogen nucleic acid 13-plex detection (oropharyngeal swab) (three cases), both of which confirmed the presence of hBoV 1. Out of the six children with PB, two were girls and four were boys. Their ages ranged from 10 months to 4 years old. Common symptoms reported by all patients included fever, cough, and wheezing. Chest high-resolution computed tomography scans revealed atelectasis in six cases, in addition to pneumonia. After the removal of the plastic bronchi via bronchoscopy, the airway obstruction symptoms in the children were relieved, and no recurrence was observed during the follow-up period. Pathological findings indicated cellulose exudation and inflammatory cell infiltration, consistent with nonlymphatic PB. CONCLUSION: When children infected with hBoV 1 exhibit persistent or worsening symptoms such as cough, fever, and wheezing despite treatment, clinicians should remain highly vigilant for the potential occurrence of PB. Bronchoscopy plays a crucial role not only in diagnosing the presence of a plastic bronchus but also in effectively treating PB.

Pseudomembranous necrotizing laryngotracheobronchitis due to Mycoplasma pneumoniae: a case report and literature review.

BACKGROUND: Pseudomembranous necrotizing laryngotracheobronchitis refers to an acute diffuse necrotizing inflammation in the mucosa of the larynx, trachea, and bronchus. It often occurs in infants and children having viral infections secondary to bacterial infections. Mycoplasma pneumoniae (M. pneumoniae) is a common pathogen that causes pneumonia in children. In recent years, serious complications due to M. pneumoniae infection, including necrotizing pneumonia, pulmonary embolism, and pleural effusion, have been increasingly reported. CASE PRESENTATION: An 11-year-old girl was admitted to our unit with cough, fever, and hoarseness persistent for a week. The results of the M. pneumoniae serological test, PCR examination with bronchial aspirate and bronchoalveolar lavage fluid (BALF), next-generation sequencing (mNGS) for BALF, all suggested the presence of M. pneumoniae infection. High-resolution CT scanning of the chest showed inflammation of the middle and lower lobes of the right lung. By bronchoscopy, the necrosis of the vocal cords, trachea, and bronchial mucosa was observed; each bronchial lumen contained a large amount of white viscous sputum. Pathological findings for bronchial mucosa suggested inflammatory necrosis. After administration of azithromycin and glucocorticoids, the symptoms of the patients were ameliorated. After 2 weeks post-discharge, the X-ray scan of her chest indicated the pneumonia resolution in the right lung. CONCLUSIONS: In patients with pneumonia due to M. pneumoniae infection, which causes obvious hoarseness, bronchoscopy is necessary even if the lung lesions are not massively consolidated. When necrotizing lesions of the larynx, trachea, and bronchi are detected by bronchoscopy, the necrotic tissues in the corresponding parts should be conducted tissue biopsy for pathological examination. Apart from macrolide antibiotics, the administration of small doses of glucocorticoids is necessary.

Genotyping of Mycoplasma pneumoniae in nasopharyngeal aspirate from children with pneumonia in Zhejiang Province / 中华儿科杂志

<p><b>OBJECTIVE</b>The P1 protein of Mycoplasma pneumoniae (MP) plays an important role in the pathogenesis of MP pneumonia. It mediates the attachment of the pathogen to host cells and elicits a strong humoral immune response during infection. In early studies, only two types of MP P1 genes were assumed to exist. Later, eight subtypes of MP P1 genes and some variations of P1 gene were reported. However, there are no related reports in China until now. This study aimed to understand epidemiology of MP subtype in Zhejiang province, China, as well as the relationship between MP subtype and clinical severity of MP pneumonia.</p><p><b>METHOD</b>Clinical samples were collected by nasopharyngeal aspiration from children with MP pneumonia hospitalized in the Children's Hospital of Zhejiang University School of Medicine from February to December in 2009. P1 gene fragment was amplified by using PCR method (with primers of ADH1/ADH2 and ADH3/ADH4, respectively). Then ADH1/ADH2-generated fragments were digested with HaeIII, HpaII, Sau3A, and the ADH3/ADH4-generated fragments digested with HaeIII, Sau3A, HhaI, RsaI. The MP P1 subtypes were determined based on resulting fragments. Part of samples were selected for sequencing. The clinical data of different MP subtype pneumonia were compared.</p><p><b>RESULT</b>A total of 300 hospitalized children with MP pneumonia were enrolled in this study. All the samples produced specific bands for MP P1 gene after PCR with primers of ADH1/ADH2 and ADH3/ADH4 respectively. By restrictive fragment length polymorphism analysis, 297 clinical specimens showed the characteristic band patterns for P1 type 1 identical to Mp129, and only 3 clinical specimens showed the characteristic band pattern for P1 type 2 identical to MP-FH. All P1 type 1 and P1 type 2 showed the same subtype bands respectively, as subtype 1b and 2a. After sequencing, one synonymous point mutation in P1 type 1 was identified relative to the MP129 P1 sequence at nucleotide position (nt) 208(G→A). Three cases with P1 type 2 MP pneumonia were found to have liver damage, and longer hospital stay and fever duration than P1 type 1, but no statistically significant difference was found.</p><p><b>CONCLUSION</b>Clinical samples can be used directly for genotyping of MP. The dominating type of MP in Zhejiang Province was P1 type 1 subtype 1b. But whether there was any relationship between MP subtype and clinical severity remains to be clarified.</p>

Effect of inhaled nitric oxide on surfactant protein A and mannose binding ability in the lung of neonatal rats with hyperoxia-induced lung injury / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the effect of inhaled nitric oxide (NO) on surfactant protein A (SP-A) and mannose binding ability (MBA) in neonatal rats with hyperoxia-induced lung injury.</p><p><b>METHODS</b>Sixty-four neonatal rats were randomly exposed to room air (Control group), >95% oxygen for 6 days (Hyperoxia group), 10 ppm NO for 24 hrs (NO group), and >95% oxygen for 6 days along with 10 ppm NO for 24 hrs (Hyperoxia + NO group). After 2 and 6 days of exposure, the lung pathologic changes, gene and protein expressions of SP-A and MBA were measured.</p><p><b>RESULTS</b>The rats from the Hyperoxia group presented with obvious lung injuries. The SP-A expressions of mRNA (0.81 +/- 0.04 vs 1.53 +/- 0.25) and protein (59.45 +/- 18.37 vs 89.77 +/- 16.41) in the Hyperoxia group decreased significantly 2 days after exposure but increased significantly 6 days after exposure (SP-A mRNA 0.81 +/- 0.02 vs 0.63 +/- 0.03; SP-A protein 93.57 +/- 13.71 vs 47.73 +/- 21.69) compared with those of the Control group (P < 0.05). NO treatment alleviated the hyperoxia-induced pathologic injuries 2 days after exposure. The SP-A mRNA expression (0.55 +/- 0.91) in the Hyperoxia + NO group was significantly reduced as compared to both the Control and Hyperoxia groups (P < 0.05), and the SP-A protein expression (55.12 +/- 17.53) in the Hyperoxia + NO group was noticeably lower than that of the Control group (P < 0.01) 2 days after exposure. The SP-A protein expression in the Hyperoxia + NO group (67.33 +/- 18.59) was significantly lower than that of the Hyperoxia group 6 days after exposure (P < 0.05). Two days after exposure, the NO group had significantly higher MBA than the Control group (0.821 +/- 0.133 vs 0.58 +/- 0.158); the Hyperoxia + NO group had significantly higher MBA than the Hyperoxia group (0.43 +/- 0.175 vs 0.738 +/- 0.141) (P < 0.05).</p><p><b>CONCLUSIONS</b>Inhaled low dose NO may decrease SP-A protein expression and increase MBA of the lung tissue. This lessens the pathologic lung injury in neonatal rats with hyperoxia.</p>

Study on the relations between epidemiology of respiratory syncytial infection in children and climate factors in Hangzhou / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the epidemiolgy of respiratory syncytial virus (RSV) infection in children and its relations to climate factors in Hangzhou.</p><p><b>METHODS</b>Monthly positive rate of RSV in pneumonia inpatients and climate factor including mean air temperature, mean relative humidity and rainy days per month were continuously observed for 3 years. Correlation analysis for RSV positive rate and these three climate factors were performed using partial correlation, and regression methods between the positive rate and significant factor was done.</p><p><b>RESULTS</b>13 642 cases were detected and 25.8% showed positive of RSV. The positive rate of RSV in children < or =1 years old, 1-3 years old, > 3 years old were 33.1%, 19.7% and 5.1% respectively with significant difference (chi2 = 763.7, P = 0.000). Rate of RSV infection was increased from December and kept in high level until May or April next year, but were varied at different years. Partial correlations between positive rate and rainy days, mean relative humidity, and mean air temperature per month were 0.32 (P= 0.066), -0.27 (P = 0.117) and -0.83 (P = 0.000) respectively. The regression equation of RSV positive rate and mean air temperature was: RSV positive rate (%) = 52.933 - 1.914 x mean air temperature (degrees C).</p><p><b>CONCLUSION</b>RSV was one of the main factors causing of pneumonia in children while the highest infectious rate was in children < or =1 year old and infectious rate reduced along with the increase of age. Low air temperature was the main factor affecting the epidemiology of RSV. RSV was prevalent both in spring and winter in Hangzhou area.</p>

Viral etiology of pneumonia in children / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the viral pathogen of pneumonia in children.</p><p><b>METHODS</b>A total of 13 642 cases of children pneumonia in 3 years were enrolled in this study. Antigens of viral pathogen in respiratory excretion, including respiratory syncytial virus (RSV), type 1, 2 and 3 parainfluenza virus, type A and B influenza virus, and adenovirus were detected by direct immunofluorescence method.</p><p><b>RESULTS</b>Viral pneumonia accounted for 34.3% of all cases, including 25.8% cases of RSV, 4.7% of parainfluenza virus, 2.4% of type A influenza virus, 0.2% of type B influenza virus and 1.3% of adenovirus. Coinfection was found in 20 cases, in which 17 cases (85%) were infected with RSV and another virus. Positive rates of RSV in children < or = 1 year, 1 to 3 years, and >3 years were 33.1%, 19.7% and 5.1% with a significant difference (chi(2)(trend)=763.4, P < 0.001). The positive rate of adenovirus in children < or =1 year (0.7%) was significantly lower than that in children aged 1 to 3 years and in children >3 years (2.3% and 2.5%) (all P<0.01). The positive rate of type A influenza virus in children aged 1 to 3 years was higher than that in children < or =1 year (chi(2)=18.2, P<0.01). Type 1 parainfluenza virus was found in 1.2% children aged 1 to 3 years with most prevalence (P<0.05). Infection rates of type 3 parainfluenza in children < or =1 year, 1 to 3 years, and >3 years were 4.7%, 3.2% and 1.4% respectively with a significant difference (chi(2)(trend)=52.4, P<0.01). Although there were some differences of infection rate of RSV in different years, it tended to increase from November to next April with a highest rate of 62.8%. Type 3 parainfluenza virus and Type A influenza virus were almost sporadic while type A influenza virus was epidemic in August 2003 with an infection rate of 15.7%.</p><p><b>CONCLUSION</b>The highest infection rate of viral pathogen of pneumonia in children is RSV and the follows are parainfluenza, influenza and adenovirus in turn.</p>