Analysis of the risk factors and clinical features of Mycoplasma pneumoniae pneumonia with embolism in children: a retrospective study

Pulmonary Thrombotic Complication of Mycoplasma pneumoniae Pneumonia in Chinese Children: Clinical Feature and Risk Factor Analysis

BACKGROUND

Thrombotic disease is a rare but severe complication of Mycoplasma pneumoniae pneumonia in children, with pulmonary thrombosis (PT) being the most frequent type. This study aims to describe the clinical features of pediatric severe Mycoplasma pneumoniae pneumonia (SMPP) patients with PT, and to identify risk factors predictive of PT development in this population.

METHODS

We retrospectively enrolled 60 children with SMPP complicated by PT who were admitted to Children's Hospital Affiliated to Zhengzhou University from January 2019 to October 2023. We reviewed their demographic data, laboratory tests and imaging examinations to describe their clinical features. We used multivariate logistic regression analysis to identify significant risk factors for PT in SMPP.

RESULTS

The PT group exhibited higher incidences of chest pain, hemoptysis, inflammation and elevated D-dimer levels, as well as more severe pulmonary damage and transaminitis complication, compared to the non-PT group. The left pulmonary artery was the predominant location of PT in SMPP children. A multivariate analysis revealed that C-reactive protein (CRP) and D-dimer were significant predictors of PT in SMPP patients, with odds ratios of 1.10 and 3.37, respectively. The optimal cutoff values of CRP and D-dimer for predicting PT in SMPP were 76.73 mg/L and 3.98 µg/mL, respectively.

CONCLUSIONS

In SMPP, CRP >76.73 mg/L and D-dimer >3.98 µg/mL are independent predictors of PT. These findings suggest that SMPP-induced excessive inflammation may contribute to PT pathogenesis. Early and intensive anticoagulant, anti-inflammatory and antimycoplasma therapy may improve the disease course and prognosis.

Establishment of a Mouse Model of Mycoplasma pneumoniae-Induced Plastic Bronchitis

Plastic bronchitis (PB) constitutes a life-threatening pulmonary disorder, predominantly attributed to Mycoplasma pneumoniae (MP) infection. The pathogenic mechanisms involved remain largely unexplored, leading to the absence of reliable approaches for early diagnosis and clear treatment. Thus, the present investigation aimed to develop an MP-induced mouse model of PB, thereby enhancing our understanding of this complex condition. In the first stage, healthy BALB/c mice were utilized to investigate the optimal methods for establishing PB. This involved the application of nebulization (15-20 min) and intratracheal administration (6-50 μL) with 2-chloroethyl ethyl sulfide (CEES) concentrations ranging from 4.5% to 7.5%. Subsequently, the MP model was induced by administering an MP solution (2 mL/kg/day, 108 CFU/50 μL) via the intranasal route for a duration of five consecutive days. Ultimately, suitable techniques were employed to induce plastic bronchitis in the MP model. Pathological changes in lung tissue were analyzed, and immunohistochemistry was employed to ascertain the expression levels of vascular endothelial growth factor receptor 3 (VEGFR-3) and the PI3K/AKT/mTOR signaling pathway. The administration of 4.5% CEES via a 6 µL trachea was the optimal approach to establishing a PB model. This method primarily induced neutrophilic inflammation and fibrinous exudate. The MP-infected group manifested symptoms indicative of respiratory infection, including erect hair, oral and nasal secretions, and a decrease in body weight. Furthermore, the pathological score of the MP+CEES group surpassed that of the groups treated with MP or CEES independently. Notably, the MP+CEES group demonstrated significant activation of the VEGFR-3 and PI3K/AKT/mTOR signaling pathways, implying a substantial involvement of lymphatic vessel impairment in this pathology. This study successfully established a mouse model of PB induced by MP using a two-step method. Lymphatic vessel impairment is a pivotal element in the pathogenetic mechanisms underlying this disease entity. This accomplishment will aid in further research into treatment methods for patients with PB caused by MP.

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.

[Risk factors for embolism in children with refractory Mycoplasmapneumoniae pneumonia and construction of a nomogram model for prediction of embolism]

OBJECTIVES

To study the risk factors for embolism in children with refractory Mycoplasma pneumoniae pneumonia (RMPP) and to construct a nomogram model for prediction of embolism.

METHODS

This retrospective study included 175 children diagnosed with RMPP at Children's Hospital Affiliated toZhengzhou University from January 2019 to October 2023. They were divided into two groups based on the presence of embolism: the embolism group (n=62) and the non-embolism group (n=113). Multivariate logistic regression analysis was used to screen for risk factors of embolism in children with RMPP, and the R software was applied to construct the nomogram model for prediction of embolism.

RESULTS

Multivariate logistic regression analysis indicated that higher levels of D-dimer, interleukin-6 (IL-6) and neutrophil to lymphocyte ratio (NLR), lung necrosis, and pleural effusion were risk factors for embolism in children with RMPP (P<0.05). The area under the curve of the nomogram model for prediction of embolism constructed based on the aforementioned risk factors was 0.912 (95%CI: 0.871-0.952, P<0.05). The Hosmer-Lemeshow goodness-of-fit test showed that the model had a good fit with the actual situation (P<0.05). Calibration and decision curve analysis indicated that the model had high predictive efficacy and clinical applicability.

CONCLUSIONS

Higher levels of D-dimer, IL-6 and NLR, lung necrosis, and pleural effusion are risk factors for embolism in children with RMPP. The nomogram model based on these risk factors has high clinical value for predicting embolism in children with RMPP.

Intracardiac and Cerebral Thrombosis Complicated With Mycoplasma Pneumonia

A seven-year-old girl developed multiposition thrombosis after fever and respiratory symptoms. Chest computed tomography (CT) scan demonstrated bilateral infiltrates, consolidation of the right lower lobe, and pleural effusion in the right lung field. Brain magnetic resonance imaging (MRI) showed multiple abnormal signals in the brain with limited diffusion, and cerebral infarction could not be excluded. Echocardiography revealed hypoechoic mitral valve tips, which are likely to be suspected as vegetation. Mycoplasma pneumoniae infection was clarified by a four-fold increase in IgG antibodies to M. pneumoniae sera. D-dimer levels were elevated increasingly. We found and reported this rare pediatric case of an M. pneumoniae-induced severe pneumonia complicated with intracardiac and cerebral thrombosis. We investigate the clinical characteristics, diagnosis, and treatment of refractory mycoplasma pneumonia complicated with intracardiac and cerebral thrombosis in children.

A retrospective study of the clinical characteristics of 9 children with pulmonary embolism associated with Mycoplasma pneumoniae pneumonia

OBJECTIVE

The aim of this study was to analyze the clinical characteristics and treatment of children with Mycoplasma pneumoniae pneumonia (MPP) who also present with pulmonary embolism (PE).

METHODS

This retrospective analysis examined the demographic data, clinical manifestations, laboratory tests, imaging characteristics, therapy, and prognosis of nine cases of children with Mycoplasma pneumoniae pneumonia (MPP) complicated by pulmonary embolism (PE). The study focused on patients admitted to the respiratory department of Tianjin Children's Hospital between January 2018 and December 2021.

RESULTS

The age range of the patients was 3 to 8 years old, with a median age of 7.5 years. The median number of days from pulmonary infection to the diagnosis of embolism was 14 days. All patients had refractory Mycoplasma pneumoniae pneumonia (RMPP). Among them, three patients reported chest pain, one of whom had hemoptysis, while five patients had dyspnea, and six patients experienced radiating pain at unusual sites. Five out of the nine children tested positive for lupus anticoagulant (LA), five for anticardiolipin antibody (ACA), three for anti-2-glycoprotein antibody IgM, four for reduced protein S or protein C activity, and three for elevated coagulation factor VIII. Moreover, six out of the nine children tested positive for antinuclear antibodies. All the children underwent CT pulmonary angiograms, which revealed filling defects. After sequential low-molecular heparin anticoagulation with rivaroxaban, nine children in this study showed a good prognosis, with two of them receiving thrombolytic therapy for combined cardiac embolism. Follow-up at 0.5-9 months showed the gradual resolution of the emboli in all 9 children, with no thrombotic recurrences and normalized autoantibodies and thrombophilia markers.

CONCLUSIONS

The majority of cases involving Mycoplasma pneumoniae pneumonia (MPP) combined with pulmonary embolism (PE) were diagnosed with refractory MPP (RMPP). However, PE did not always occur in the advanced stages of the disease. Most patients presented with transient autoantibody positivity, abnormal coagulation, and fibrinolytic balance. With timely treatment, the prognosis of MPP combined with PE is generally good. Additionally, rivaroxaban treatment has been shown to be safe and effective.