Characteristics and Outcomes of Mycoplasma Pneumoniae Pneumonia Associated with Pulmonary Embolism and Necrotizing Pneumonia in Children.

Purpose: To explore the clinical characteristics, treatment, and long-term prognosis of mycoplasma pneumoniae pneumonia (MPP) combined with pulmonary embolism (PE) in children. Patients and Methods: The medical records of 16 children who were diagnosed with MPP associated with PE between January 2016 and January 2023 at Children's Hospital, Zhejiang University School of Medicine were retrospectively reviewed. Results: The average age patients were 8.24 ± 1.99 years. All cases were diagnosed with refractory mycoplasma pneumoniae pneumonia (RMPP) and presented complications in the form of necrotizing pneumonia (NP). The main symptoms observed were cough and fever (n = 16, 100%), chest pain (n = 8, 50%), dyspnea (n = 8, 50%), and hemoptysis (n = 4, 25%). In these cases, 12 patients had involvement of the pulmonary artery, 3 patients experienced issues with the pulmonary vein, and 1 patient had simultaneous involvement of both the pulmonary artery and pulmonary vein. Among the 12 pulmonary artery embolism cases, 6 involved the right pulmonary artery, 4 involved the left pulmonary artery, and 2 involved both the right and left pulmonary arteries. The mean D-dimer level was 8.50 ± 4.76 mg/L. All patients received anticoagulant therapy, and after treatment, there was a significant improvement in their symptoms and lung lesions. Conclusion: Children with RMPP, chest pain, hemoptysis, and elevated D-dimer levels should be closely monitored for the potential development of PE. The co-occurrence of MPP and PE often involves the presence of NP. In cases of confirmed PE, anticoagulation therapy may be a suitable consideration. PE and NP resulting from MPP generally had a favorable overall prognosis.

Identification of mycoplasma pneumonia in children based on fusion of multi-modal clinical free-text description and structured test data.

Mycoplasma pneumonia may lead to hospitalizations and pose life-threatening risks in children. The automated identification of mycoplasma pneumonia from electronic medical records holds significant potential for improving the efficiency of hospital resource allocation. In this study, we proposed a novel method for identifying mycoplasma pneumonia by integrating multi-modal features derived from both free-text descriptions and structured test data in electronic medical records. Our approach begins with the extraction of free-text and structured data from clinical records through a systematic preprocessing pipeline. Subsequently, we employ a pre-trained transformer language model to extract features from the free-text, while multiple additive regression trees are used to transform features from the structured data. An attention-based fusion mechanism is then applied to integrate these multi-modal features for effective classification. We validated our method using clinic records of 7157 patients, retrospectively collected for training and testing purposes. The experimental results demonstrate that our proposed multi-modal fusion approach achieves significant improvements over other methods across four key performance metrics.

Cryptococcosis with pulmonary cavitation in an immunocompetent child: a case report and literature review.

BACKGROUND: Pulmonary cryptococcosis (PC) rarely occurs in immunocompetent children. CASE PRESENTATION: A 13-year-old boy was admitted to the First Affiliated Hospital of Ningbo University in February 2023 with complaints of cough and chest pain. Physical examination showed slightly moist rales in the right lung. Chest computed tomography (CT) suggested a lung lesion and cavitation. Blood routine test, lymphocyte subsets, immunoglobulin, and complement tests indicated that the immune system was normal. However, the serum cryptococcal antigen test was positive. Next-generation sequencing revealed Cryptococcus infection. The child was diagnosed with PC and was discharged after treating with fluconazole 400 mg. Four months later, chest CT showed that the lung lesion diminished, and reexamination of serum cryptococcal antigen test turned positive. CONCLUSION: PC should be considered in an immunocompetent child with pulmonary cavities with nonspecific symptoms.

A missed foreign body aspiration masquerading as congenital pulmonary airway malformation in a nine-year-old boy: A case report and literature review.

Although airway foreign body aspiration (FBA) is a common occurrence in any age group, unrecognized and retained foreign bodies in lungs may result in severe complications, such as lung abscess or bronchiectasis. In rare cases, FBA may present with similar clinical features as many other diseases (e.g. asthma, tumor, pulmonary eosinophilia). Here, we report a rare case of missed FBA in a nine-year-old boy, whose chest CT scan was suggestive of a cavitary lesion in the left lower lobe mimicking congenital pulmonary airway malformation (CPAM). However, surprisingly, flexible bronchoscopy revealed a peanut lodged in the lateral basal segment of left lower lobe, which was subsequently retrieved by a forceps and avoided unnecessary surgical lobectomy. Therefore, FBA can mimic other disorders (e.g. CPAM), and a high index of suspicion and additional diagnostic techniques (e.g. flexible bronchoscopy) may be required to distinguish them. Additionally, FBA should be considered in the differential diagnosis of respiratory disorders in children even lack of aspiration history.

Clinical features of Streptococcus intermedius infection in children: a case series study.

Introduction: Streptococcus intermedius is an opportunistic pathogen associated with prolonged hospital stays and high mortality rates in adults. However, little is currently known about the clinical features of Streptococcus intermedius infection in children. Methods: This retrospective case series study included 40 children diagnosed with Streptococcus intermedius, confirmed through bacterial cultures or high-throughput sequencing. Antibiotic resistance was assessed through susceptibility testing. The site and clinical manifestations were evaluated for all patients. Results: The common infection sites were the abdominal cavity, skin and soft tissue, intracranial, and invasive pulmonary, with the abdominal cavity being the most frequently affected. The drug susceptibility test showed 100% sensitivity to ceftriaxone, levofloxacin, chloramphenicol, vancomycin, and linezolid, 92.6% sensitivity to penicillin, 73.3% resistance to erythromycin, and 76.7% resistance to clindamycin. Besides antibiotic therapy, surgical intervention or pus drainage was often necessary. Lung imaging of four patients revealed pulmonary abscesses, nodules, or encapsulated pleura. Two cases yielded positive culture results, while three were identified as positive through high-throughput nucleotide sequencing of pleural effusion. Discussion: In children with Streptococcus intermedius infection, emphasis should be placed on the risk of pus or abscess formation. In cases of pulmonary abscess and pleural effusion, especially in male children, Streptococcus intermedius should be suspected even if the culture is negative. Improvements in high-throughput nucleotide sequencing are required to reduce misdiagnosis rates.

An unusual presentation of necrotizing pneumonia caused by foreign body retention in a 20-month-old child: A case report and literature review.

Necrotizing pneumonia (NP) is a rare but serious complication that occurs after foreign body retention. We report a case of severe NP in an infant caused by foreign body retention in the airway with no choking history. After a timely tracheoscopy and effective antibiotic treatment, her initial clinical symptoms were alleviated. However, she subsequently exhibited pulmonary manifestations of necrotizing pneumonia. To reduce the risk of NP from foreign body aspiration, for patients with airway obstruction and asymmetrical opacity of both lungs, timely diagnostic bronchoscopic evaluation is essential.

Successful management of tracheal lobular capillary hemangioma with arterial embolization followed by electrosurgical snaring via flexible bronchoscopy in an 11-year-old boy: A case report and literature review.

Lobular capillary hemangioma (LCH), previously known as pyogenic granuloma, is a benign vascular lesion commonly found within the oral and nasal cavities. However, it is rarely encountered within the trachea, especially in pediatric patients, where it manifests as hemoptysis, cough, and wheeze, and is frequently misdiagnosed as bronchitis or asthma. There is limited literature on the presentation, behavior, and management of tracheal LCH. Herein, we describe a rare case of tracheal LCH in an 11-year-old boy with a history of hemoptysis, which was successfully managed with arterial embolization followed by electrocautery loop snaring via flexible bronchoscopy. No complications occurred during and after the procedure. A review of the relevant literature is also provided. Our case is unique, given the therapeutic strategy utilized for pediatric tracheal LCH, and reminds physicians to be aware of tracheal LCH in the differential diagnosis for hemoptysis.

Case report: Primary alveolar soft-part sarcoma of the lung in a child.

Alveolar soft-part sarcoma involving the lung is mostly metastatic in nature, while primary alveolar soft-part sarcoma involving the lung occurs more rarely. Herein, we report a rare case of a patient with primary alveolar soft-part sarcoma of the lung, which may represent the earliest onset of this condition reported thus far. In this patient, surgery was performed to excise the lesion to the greatest extent possible, and the combination of surgery with chemoradiotherapy and an antiangiogenic agent may provide an important reference for the development of standard or first-line treatment for such pediatric patients.

Causal relationship between outdoor atmospheric quality and pediatric asthma visits in hangzhou.

Many air pollutants and climate variables have proven to be significantly associated with pediatric asthma and have worsened asthma symptoms. However, their exact causal effects remain unclear. We explored the causality between air pollutants, climate, and daily pediatric asthma patient visits with a short-term lag effect. Based on eight years of daily environmental data and daily pediatric asthma patient visits, Spearman correlation analysis was used to select the air pollutants and climate variables that correlated with daily pediatric asthma patient visits at any time (with a lag of 1-6 days). We regarded these environmental variables as treatments and built multiple- and single-treatment causal inference models using the Dowhy library (a Python library for causal inference by graphing the model, quantitatively evaluating causal effects, and validating the causal assumptions) to estimate the quantitative causal effect between these correlated variables and daily pediatric asthma patient visits in lag time. The multiple-treatment causal inference model was a model with 8 treatments (Visibility, Precipitation, PM10, PM2.5, SO2, NO2, AQI and CO), 1 outcome (daily pediatric asthma patients visits), and 5 confounders (Humidity, Temperature, Sea level pressure, wind speed and unobserved confounders "U"). Single-treatment causal inference models were 8 models, and each model has 1 treatment, 1 outcome and 12 confounders. Spearman correlation analysis showed that precipitation, wind speed, visibility, air quality index, PM2.5, PM10, SO2, NO2, and CO were significantly associated variables at all times (p < 0.05). The multiple-treatment model showed that pooled treatments had significant causality for the short-term lag (lag1-lag6; p < 0.05). Causality was mainly due to SO2. In the single-treatment models, visibility, SO2, NO2, and CO exhibited significant causal effects at any one time (p < 0.05). SO2 and CO exhibited stronger positive causal effects. The causal effect of SO2 reached its maxima (causal effect = 11.41, p < 0.05) at lag5. The greatest causal effect of CO appeared at lag3 (causal effect = 10.67, p < 0.05). During the eight year-period, the improvements in SO2, CO, and NO2 in Hangzhou were estimated to reduce asthma visits by 8478.03, 3131.08, and 1341.39 per year, respectively. SO2, NO2, CO, and visibility exhibited causal effects on daily pediatric asthma patient visits; SO2 was the most crucial causative variable with a relatively higher causal effect, followed by CO. Improvements in atmospheric quality in the Hangzhou area have effectively reduced the incidence of asthma.

Effects of subcutaneous immunotherapy in allergic rhinitis children sensitive to dust mites.

BACKGROUND: Subcutaneous immunotherapy (SCIT) is now the only treatment that can modify the natural course of allergic rhinitis (AR). However, not all children with AR benefit from SCIT. OBJECTIVE: To evaluate the efficacy of SCIT in dust-mites-induced AR children and explore correlative factors predicting treatment response to SCIT. METHODS: 225 children aged 4-17 years old with AR were recruited from January 2016 to September 2019, and monitored at baseline, 4, 12, and 24 months after the start of SCIT treatment. The visual-analogue-score (VAS) was used to assess the clinical symptoms. Multivariate binary logistic regression analyses and receiver operating characteristic curves were used to explore correlative factors in predicting the efficacy of SCIT. RESULTS: The significant declines in VAS started after 4 months of SCIT and continued to improve throughout the study compared with baseline. An increase in children's age (OR=0.688, 95%CI: 0.479-0.988) and those with allergic history (OR=0.097, 95%CI: 0.009-1.095) were negatively associated with the risk of poor efficacy. Polysensitized children were more likely to suffer poor efficacy (OR=15.511 95%CI: 1.319-182.355). The clinical response at month 4 (r=0.707) and month 12 (r=0.925) was related to that at month 24. The area under the curve (AUC) for improvement at month 4 and month 12 was 0.746 and 0.860, respectively. CONCLUSION: Our study confirmed the clinical efficacy of SCIT in AR children. Children with younger age, negative allergic history, and multiple allergens may predict a worse efficacy. The onset of action and the clinical response to SCIT in the second year can be predicted as early as by month 4.

Pharmacokinetics and Tissue Distribution of Nasal Spray of a Novel Muscarinic Receptor Blocker, 101BHG-D01, in Dogs and Rats.

BACKGROUND: 101BHG-D01 is a novel selective anti-muscarinic (M) 3 receptor-blocking drug. 101BHG-D01 nasal spray is intended to be used to relieve sneezing and runny nose symptoms caused by allergic rhinitis. METHODS: In this study, we examined the plasma pharmacokinetics, tissue distribution, and major excretion mode of 101BHG-D01 in Beagle dogs and rats following nasal spray and intranasal administration, respectively, using HPLC-MS/MS. RESULTS/DISCUSSION: We found that the pharmacokinetics of 101BHG-D01 was linear in dogs. 101BHG-D01 entered the bloodstream rapidly following nasal spray. Its plasma half-life was approximately 6 h and resided at least 24 h in the body. Moreover, 101BHG-D01 retained a significant amount in the nasal cavity. Finally, we found that 101BHG-D01 was eliminated mainly in the form of stools in rats. CONCLUSION: In conclusion, we provided pertinent reference information regarding the design and optimization of drug delivery regimens for clinical trials.

Single-cell transcriptomic characterization reveals the landscape of airway remodeling and inflammation in a cynomolgus monkey model of asthma.

Monkey disease models, which are comparable to humans in terms of genetic, anatomical, and physiological characteristics, are important for understanding disease mechanisms and evaluating the efficiency of biological treatments. Here, we established an A.suum-induced model of asthma in cynomolgus monkeys to profile airway inflammation and remodeling in the lungs by single-cell RNA sequencing (scRNA-seq). The asthma model results in airway hyperresponsiveness and remodeling, demonstrated by pulmonary function test and histological characterization. scRNA-seq reveals that the model elevates the numbers of stromal, epithelial and mesenchymal cells (MCs). Particularly, the model increases the numbers of endothelial cells (ECs), fibroblasts (Fibs) and smooth muscle cells (SMCs) in the lungs, with upregulated gene expression associated with cell functions enriched in cell migration and angiogenesis in ECs and Fibs, and VEGF-driven cell proliferation, apoptotic process and complement activation in SMCs. Interestingly, we discover a novel Fib subtype that mediates type I inflammation in the asthmatic lungs. Moreover, MCs in the asthmatic lungs are found to regulate airway remodeling and immunological responses, with elevated gene expression enriched in cell migration, proliferation, angiogenesis and innate immunological responses. Not only the numbers of epithelial cells in the asthmatic lungs change at the time of lung tissue collection, but also their gene expressions are significantly altered, with an enrichment in the biological processes of IL-17 signaling pathway and apoptosis in the majority of subtypes of epithelial cells. Moreover, the ubiquitin process and DNA repair are more prevalent in ciliated epithelial cells. Last, cell-to-cell interaction analysis reveals a complex network among stromal cells, MCs and macrophages that contribute to the development of asthma and airway remodeling. Our findings provide a critical resource for understanding the principle underlying airway remodeling and inflammation in a monkey model of asthma, as well as valuable hints for the future treatment of asthma, especially the airway remodeling-characterized refractory asthma.

Interpretable modeling and discovery of key predictors for pneumonia diagnosis in children based on electronic medical records.

Background: Community-acquired pneumonia is one of the most common infectious diseases in children and is a leading cause of death among children under 5 years of age, resulting in high rates of antibiotic usage and hospitalization. It is of extremely practical significance to make full use of the existing electronic medical records to study pneumonia and to establish automatic diagnosis models for pneumonia. Methods: We established pneumonia diagnosis models of Bayesian network using a total of 13,448 electronic medical records. We investigated learning network structure and parameter estimation and evaluated different structure learning strategies and various modeling methods. By identifying the key predictors of model, the pneumonia status was analyzed. Results: The performance of the proposed Bayesian network was evaluated using a set of 3361 cases with a precision of 0.7861, a recall of 0.9889, and an F1-score of 0.8759. On an independent external validation set containing 4925 cases, Bayesian network achieved a precision of 0.7382, a recall of 0.9947, and an F1-score of 0.8475. Our proposed Bayesian network outperformed all other methods, including CatBoost, XGBoost, LightGBM, logistic regression, and ridge classification. Conclusion: The appropriate feature selection improved the performance of Bayesian networks. The proposed Bayesian network had good generalizability and could be directly applied to clinical research centers. And the key predictors identified by the network demonstrated good clinical interpretability, allowing for a better understanding of pneumonia status and complications. This study had important clinical value and practical significance for the research and diagnosis of pediatric pneumonia.

A reference single-cell regulomic and transcriptomic map of cynomolgus monkeys.

Non-human primates are attractive laboratory animal models that accurately reflect both developmental and pathological features of humans. Here we present a compendium of cell types across multiple organs in cynomolgus monkeys (Macaca fascicularis) using both single-cell chromatin accessibility and RNA sequencing data. The integrated cell map enables in-depth dissection and comparison of molecular dynamics, cell-type compositions and cellular heterogeneity across multiple tissues and organs. Using single-cell transcriptomic data, we infer pseudotime cell trajectories and cell-cell communications to uncover key molecular signatures underlying their cellular processes. Furthermore, we identify various cell-specific cis-regulatory elements and construct organ-specific gene regulatory networks at the single-cell level. Finally, we perform comparative analyses of single-cell landscapes among mouse, monkey and human. We show that cynomolgus monkey has strikingly higher degree of similarities in terms of immune-associated gene expression patterns and cellular communications to human than mouse. Taken together, our study provides a valuable resource for non-human primate cell biology.

Mild Encephalitis/Encephalopathy with Reversible Splenial Lesion Associated with Scrub Typhus in a Child: A Case Report.

Background: Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a rare clinicoradiological syndrome characterized by transient mild encephalopathy and magnetic resonance imaging (MRI) findings of a reversible lesion in the splenium of the corpus callosum (SCC). Multiple causes have been proposed for the pathogenesis of MERS, with infection as the most pre-eminent. Case Presentation: We report the case of a 10-year-old girl with MERS due to scrub typhus. Her clinical manifestations of headache and drowsiness, together with lesions involving the SCC, as shown by MRI, and their complete resolution upon follow-up fulfilled the diagnosis of MERS. At the same time, the characteristic eschar of the skin and the positive Weil-Felix test result confirmed the existence of scrub typhus infection. Conclusions: To the best of our knowledge, we described the first pediatric case of MERS associated with scrub typhus. The case indicated that an MERS patient with fever should be considered as possibly having a scrub typhus infection. The characteristic black eschar of scrub typhus generally occurs after bite of mite that is important and useful to the doctor for making proper diagnosis.

Four Discrete Silver Iodobismuthates/Bromobismuthates with Metal Complexes: Syntheses, Structures, Photocurrent Responses, and Theoretical Studies.

Using in situ formed metal complexes of [Fe(bipy)3]2+ or [Ni(bipy)3]2+ (bipy = 2,2'-bipyridine) as templates, four new Ag-Bi-X (X = I and Br) compounds are first isolated in the metal-complex-decorated heterometallic halobismuthate family, namely [M(bipy)3]AgBiI6 (M = Fe (1), Ni (2)), [Fe(bipy)3]AgBiBr6 (3), and [Ni(bipy)3]AgBiBr6 (4). Compounds 1-4 feature discrete [AgBiX6]n2n- anions, exhibiting three polymorphisms that may be ascribed to the different stackings and the flexible condensations of [BiX6] octahedrons and [AgX4] tetrahedra/[AgX3] triangles. UV-vis diffuse reflectance analyses reveal that they are narrow band gap semiconductor materials (ca. 1.82-2.13 eV). Intriguingly, the title compounds display excellent photoelectrical switching properties, with photocurrent density following the order 3 > 4 > 2 > 1. In addition, the comparative studies of intermolecular interactions, theoretical band structures, density of states, and effective masses of three polymorphisms have also been investigated.

Primary intratracheal neurilemmoma in a 10-year-old girl: A case report.

BACKGROUND: Tracheal tumors are relatively rare in adults and uncommon in children. Tracheal neurilemmoma is a rare condition in adults that usually affects middle-aged people, but it can also occur in children. Because the clinical presentation is nonspecific and insidious, diagnosis is often delayed. The most common symptoms in these patients are stridor or wheezing (especially positional) and cough. A few patients are misdiagnosed and mistakenly treated for asthma. CASE SUMMARY: A 10-year-old girl was admitted to our unit with a 2-mo history of recurrent cough, dyspnea, and tachypnea. Her condition was more severe after exercise. Her symptoms progressed despite treatment with inhaled fluticasone/salmeterol. Flexible electronic laryngoscopy showed a red, smooth, and round mushroom-shaped mass in the trachea, about 1 cm below the vocal cords. The surface of the mass was covered with several small and discontinuous blood vessels. About 90% of the tracheal lumen was occupied by the mass. A multidisciplinary operation was performed. The surgically resected mass was diagnosed as benign neurilemmoma by immunohistochemical analysis. CONCLUSION: Intratracheal neurilemmoma is fairly rare in children. The main symptoms include coughing, wheezing, and dyspnea. The tumor's size, location, and degree of intratracheal and extratracheal invasion can be measured by chest computed tomography. The main treatment strategies used for tracheal neurilemmoma are surgical resection and endoscopic excision. Long-term follow-up is warranted for the evaluation of outcomes and complications.

Inhaled B7 alleviates bleomycin-induced pulmonary fibrosis in mice.

Treatment options for the progression of pulmonary fibrosis (PF), which ultimately causes respiratory failure, are limited. According to recent studies, recombinant human relaxin is potentially therapeutic against fibrosis and contraction during pulmonary damage. However, the production of recombinant H2 relaxin is laborious and expensive, limiting its extensive application. Thankfully, alternative research has revealed that treatment with a single-chain peptide of relaxin attenuates organ fibrosis in rodent models too, with the production of a single-chain peptide of relaxin simple and cheap; it could be therapeutic against idiopathic pulmonary fibrosis. Here, we explored the probable inhibiting effects of B7, a B chain of recombinant human relaxin, on bleomycin-induced pulmonary inflammation. Inhaled B7 efficiently reduced the number of inflammatory leukocytes and neutrophils in the bronchoalveolar lavage fluid of mice with bleomycin-induced PF, significantly improved the structure of the damaged alveolar, reduced collagen deposition, suppressed the main pathological features of idiopathic pulmonary fibrosis, i.e. the expression of both pulmonary α-smooth muscle actin and pulmonary vimentin, and inhibited the transcription of inflammation and collagen deposition-related mRNAs, including fibronectin, α-smooth muscle actin (α-SMA), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and alpha-1 type 1 collagen (Col-1a), and the expression of inflammation-related proteins, such as IL-1ß, IL-6, chemokines (KC), TIMP metallopeptidase inhibitor 1 (TIMP-1), and hydroxyproline (Hyp). Overall, our findings suggest that inhaled B7 exerts beneficial effects against pulmonary fibrosis via attenuating inflammation. It could be developed into a simple, highly effective therapeutic approach for pulmonary fibrosis.

Congenital Brucellosis: A Case Report.

Background: Brucellosis is the most common zoonotic infection worldwide, and is caused by bacterial genus Brucella. The disease is rarely transmitted through human-to-human transmission. Few cases have been reported about vertical transmission of human brucellosis. Herein, we reported a case of congenital brucellosis, with clear evidence of pathogen detected in mother's placental specimen. Case Presentation: A 34-day-old girl was admitted to the department of pulmonology with fever for 8 days. Three blood samples and one sample of cerebrospinal fluid were positive for Brucella melitensis. The diagnosis of brucellosis and B. melitensis meningitis were established, along with hyperbilirubinemia and liver dysfunction. Treatment of rifampicin (for 6 weeks) and meropenem (for 2 weeks) was administered. However, the disease relapsed within 18 days. Thereafter, a combination therapy of rifampicin and sulfamethoxazole/trimethiprim (SMZ/TMP) was administered for 8 weeks. The disease relapsed again in 42 days. For chronic brucellosis, three courses of combination therapy of rifampicin and SMZ/TMP was administered. The mother had fatigue and arthralgia for 2 weeks, fever and membrane rupture 1 day before the baby was born. B. melitensis DNA was detected in the mother's placental specimen by next-generation sequencing and bacterial identification under microscope proved chorioamnionitis. Conclusions: We reported a confirmed case of congenital brucellosis. This disease should be closely monitored even in nonepidemic areas. The treatment of brucellosis in infancy faces challenges of drug choice and disease relapse.

The Level of D-Dimer Is Positively Correlated With the Severity of Mycoplasma pneumoniae Pneumonia in Children.

Objective: Mycoplasma pneumoniae pneumonia (MPP) is an important disease in children. Studies have demonstrated that the levels of D-dimer are elevated in some children with MPP, especially those with thrombotic complications. However, the potential association between MPP and D-dimer remains unclear. In our study, we sought to explore the relationship between the levels of plasma D-dimer and clinical characteristics of MPP patients. Methods: Retrospective analysis was conducted on 356 patients who were hospitalized in our hospital for MPP between January 1, 2017, and December 31, 2019. According to the peak value of D-dimer, patients were divided into three groups: the normal group (D-dimer<0.55 mg/L), the mild-moderately elevated group (D-dimer 0.55-5.5 mg/L) and the severely elevated group (D-dimer >5.5 mg/L). The demographic and clinical information, radiological findings, laboratory data, and treatments of patients were compared among different groups. Results: 106 patients were in the normal group, 204 patients were in the mild-moderately elevated group, and 46 patients were in the severely elevated group. More severe clinical and radiographic manifestations, longer length of fever, hospital stay and antibiotic therapy duration, higher incidences of extra-pulmonary complications, refractory MPP (RMPP), severe MPP (SMPP) were found in the elevated group, when compared with the normal group (P<0.01). Meanwhile, we found that the percentage of neutrophil (N%) and CD8+ lymphocyte (CD8+%), C-reactive protein (CRP), lactate dehydrogenase (LDH), interleukin (IL)-6, IL-10, and interferon-gamma (IFN-γ) trended higher with increasing D-dimer, whereas the percentage of lymphocyte (L%) and prealbumin (PAB) trended lower (P<0.01). In addition, the proportions of patients requiring oxygen therapy, glucocorticoid, bronchoscopy, immunoglobulin use, thoracentesis, or ICU admission were significantly higher in the severely elevated group than those in the other two groups (P<0.01). Correlation analysis showed that N%, L%, CRP, LDH, IL-10, length of fever, length of stay, and length of antibiotic therapy had strong correlations with the level of D-dimer. Conclusions: MPP patients with higher levels of D-dimer had more severe clinical manifestations and needed longer duration of treatment, which might be closely related to the severity of lung inflammation after MP infection.