Recognition of refractory Mycoplasma pneumoniae pneumonia among Myocoplasma pneumoniae pneumonia in hospitalized children: development and validation of a predictive nomogram model.

BACKGROUD: The current diagnostic criteria for refractory Mycoplasma pneumoniae pneumonia (RMPP) among Mycoplasma pneumoniae Pneumonia (MPP) are insufficient for early identification, and potentially delayed appropriate treatment. This study aimed to develop an effective individualized diagnostic prediction nomogram for pediatric RMPP. METHODS: A total of 517 hospitalized children with MPP, including 131 with RMPP and 386 without RMPP (non-RMPP), treated at Lianyungang Maternal and Child Health Care Hospital from January 2018 to December 2021 were retrospectively enrolled as a development (modeling) cohort to construct an RMPP prediction nomogram. Additionally, 322 pediatric patients with MPP (64 with RMPP and 258 with non-RMPP, who were treated at the Affiliated Hospital of Xuzhou Medical University from June 2020 to May 2022 were retrospectively enrolled as a validation cohort to assess the prediction accuracy of model. Univariable and multivariable logistic regression analyses were used to identify RMPP risk factors among patients with MPP. Nomogram were generated based on these risk factors using the rms package of R, and the predictive performance was evaluated based on receiver operating characteristic (ROC) curves and using decision curve analysis (DCA). RESULTS: Multivariate analysis revealed five significant independent predictors of RMPP among patients with MPP: age (hazard ratio [HR] 1.16, 95% confidence interval [CI] 1.08-1.33, P = 0.038), fever duration (HR 1.34, 95%CI 1.20-1.50, P < 0.001), lymphocyte count (HR 0.45, 95%CI 0.23-0.89, P = 0.021), serum D-dimer (D-d) level (HR 1.70, 95%CI 1.16-2.49, P = 0.006), and pulmonary imaging score (HR 5.16, 95%CI 2.38-11.21, P < 0.001). The area under the ROC curve was 90.7% for the development cohort and 96.36% for the validation cohort. The internal and external verification calibration curves were almost linear with slopes of 1, and the DCA curve revealed a net benefit with the final predictive nomogram. CONCLUSION: This study proposes a predictive nomogram only based on five variables. The nomogram can be used for early identification of RMPP among pediatric patients with MPP, thereby facilitating more timely and effective intervention.

[Correlation between galectin-3 level in bronchoalveolar lavage fluid and cellular immunity in children with refractory Mycoplasma pneumoniae pneumonia].

OBJECTIVE: To study the correlation of galectin-3 level in bronchoalveolar lavage fluid (BALF) with Mycoplasma pneumoniae (MP) load and cellular immunity of neutrophils and macrophages in the airway in children with refractory MP pneumonia (RMPP). METHODS: A total of 64 children with RMPP who were hospitalized from January 2013 to January 2017 were enrolled. In addition to the conservative medical treatment, all the 64 children with RMPP were given bronchoalveolar lavage in the acute stage (5-7 days after admission) and 48 out of the 64 children were given bronchoalveolar lavage in the recovery stage (10-14 days after admission). Four milliliters of BALF of the affected lung lobe or segment were collected. ELISA was used to measure the level of galectin-3 in BALF supernatant. RT-PCR was used to measure MP load. Hematoxylin and eosin staining was used to measure the percentage of neutrophils and macrophages. Six children with bronchial foreign bodies were enrolled as the control group. RESULTS: The RMPP group had a significantly higher level of galectin-3 in BALF in both the acute and recovery stages than the control group (P<0.01), and the level of galectin-3 in the acute stage was significantly higher than in the recovery stage (P<0.01). The RMPP group had a significantly higher percentage of neutrophils in BALF in both the acute and recovery stages than the control group (P<0.01), and the percentage of neutrophils in the acute stage was significantly higher than in the recovery stage (P<0.01). The RMPP group had a significantly lower percentage of macrophages in BALF in both the acute and recovery stages than the control group (P<0.01), but there was no significant difference in the percentage of macrophages between the acute and recovery stages (P>0.05). The RMPP group had a significantly higher MP load in BALF in both the acute and recovery stages than the control group (P<0.01), and the MP load in the acute stage was significantly higher than in the recovery stage (P<0.01). In the children with RMPP, galectin-3 level in BALF in the acute stage was positively correlated with MP load and the percentage of neutrophils (rs=0.789 and 0.726 respectively; P<0.01). CONCLUSIONS: Galectin-3 is involved in the process of airway inflammation in children with RMPP, and the level of galectin-3 in BALF is positively correlated with MP load. RMPP is a cellular immune inflammatory lesion with the increase of neutrophils and the reduction in macrophages. Galectin-3 is closely associated with neutrophil chemotaxis and luminal infiltration in children with RMPP. MP load gradually decreases with the recovery from RMPP, but it is not completely eliminated by the immune system in the recovery stage. MP infection can increase the consumption of macrophages in children with RMPP.

Case report: Fatal infantile hypertonic myofibrillar myopathy with compound heterozygous mutations in the CRYAB gene.

Background: Fatal infantile hypertonic myofibrillar myopathy (FIHMM) is an autosomal recessive hereditary disease characterized by amyotrophy, progressive flexion contracture and ankylosis of the trunk and limb muscles, apnea and respiratory failure, and increased creatine phosphate levels. It is caused by mutations in the CRYAB gene, and only around 18 cases including genetic mutations have been reported worldwide. All patients with FIHMM develop respiratory distress, progressive stiffness of the limbs, and have a poor prognosis. However, no effective treatment for CRYAB-associated respiratory failure has been reported. Here, we report a case of FIHMM with a novel heterozygous missense mutation. Case Presentation: A 2-year-old female developed scoliosis of the lumbar spine and restrictive ventilatory dysfunction in infancy. She was admitted to the hospital with labored breathing on the third day after the second injection of inactivated poliomyelitis vaccine. Acute respiratory failure, pneumothorax, and cardiac arrest arose in the patient during hospitalization, and progressive stiffness of the trunk and limb muscles appeared, accompanied by obvious abdominal distension and an increase in phosphocreatine kinase levels. Screenings for genetic metabolic diseases in the blood and urine were normal. Electromyography revealed mild myogenic damage. A muscle biopsy indicated the accumulation of desmin, α-crystallin, and myotilin in the musculus biceps brachii, and dense granules were observed in muscle fibers using electron microscopy. Mutation analysis of CRYAB revealed a novel heterozygous missense mutation in the proband, c.302A > C (p.His101Pro) and c.3G > A (p.Met1Ile), which inherited from her asymptomatic, heterozygous carrier parents, respectively. The proband was finally diagnosed as FIHMM. One month after the FIHMM diagnosis, the child died of respiratory failure. Conclusion: We report a case of FIHMM with a novel heterozygous missense mutation of CRYAB. This finding might improve our understanding of FIHMM and highlight a novel mutation in the Chinese population.