[A multicenter retrospective study on the etiology of necrotizing pneumonia in children].

Objective: To investigate the etiology of necrotizing pneumonia (NP) in children and the clinical characteristics of NP caused by different pathogens in China. Methods: A retrospective, case-control study was performed in children with NP who were admitted to 13 hospitals in China from January 2008 to December 2019. The demographic and clinical information, laboratory data, etiological and radiological findings were analyzed. The data were divided into three groups based on the following years: 2008-2011, 2012-2015 and 2016-2019, and the distribution characteristics of the pathogens in different period were compared. Meanwhile, the pathogens of pediatric NP in the southern and northern China were compared. And the clinical characteristics of the Mycoplasma pneumoniae (MP) NP and the bacterial NP were also compared. T-test or Mann-Whitney nonparametric test was used for comparison of numerical variables, and χ2 test was used for categorical variables. Results: A total of 494 children with NP were enrolled, the median ages were 4.7 (0.1-15.3) years, including 272 boys and 222 girls. Among these patients, pathogens were identified in 347 cases and the pathogen was unclear in the remaining 147 cases. The main pathogens were MP (238 cases), Streptococcus pneumoniae (SP) (61 cases), Staphylococcus aureus (SA) (51 cases), Pseudomonas aeruginosa (13 cases), Haemophilus influenzae (10 cases), adenovirus (10 cases), and influenza virus A (7 cases), respectively. MP was the most common pathogen in all three periods and the proportion increased yearly. The proportion of MP in 2016-2019 was significantly higher than that in 2012-2015 (52.1% (197/378) vs. 36.8% (32/87), χ2=6.654, P=0.010), while there was no significant difference in the proportion of MP in 2012-2015 and that in 2008-2011 (36.8% (32/87) vs. 31.0% (9/29), χ²=0.314, P=0.575).Regarding the regional distribution, 342 cases were in the southern China and 152 in the northern China. Also, MP was the most common pathogen in both regions, but the proportion of MP was higher and the proportion of SP was lower in the north than those in the south (60.5% (92/152) vs. 42.7% (146/342), χ2=13.409, P<0.010; 7.9% (12/152) vs. 14.3% (49/342), χ2=4.023, P=0.045). Comparing the clinical characteristics of different pathogens, we found that fever and cough were the common symptoms in both single MP and single bacterial groups, but chest pain was more common (17.0% (34/200) vs. 6.1% (6/98), χ2=6.697, P=0.010) while shortness of breath and wheezing were less common in MP group (16.0% (32/200) vs. 60.2% (59/98), χ2=60.688, P<0.01; 4.5% (9/200) vs. 21.4% (21/98), χ2=20.819, P<0.01, respectively). The white blood cell count, C-reactive protein and procalcitonin in the bacterial group were significantly higher than those in the MP group (14.7 (1.0-67.1)×109/L vs. 10.5 (2.5-32.2)×109/L, 122.5 (0.5-277.3) mg/L vs. 51.4 (0.5-200.0) g/L, 2.13 (0.05-100.00) µg/L vs. 0.24 (0.01-18.85) µg/L, Z=-3.719, -5.901 and -7.765, all P<0.01). Conclusions: The prevalence of pediatric NP in China shows an increasing trend during the past years. MP, SP and SA are the main pathogens of NP, and the most common clinical symptoms are fever and cough. The WBC count, C-reactive protein and procalcitonin in bacterial NP are significantly higher than those caused by MP.

[Genetic variants in the surfactant protein C gene 218 site are associated with pediatric interstitial lung disease: seven cases study].

Objective: To investigate the clinical features and outcomes of pulmonary surfactant protein C gene (SFTPC) 218 site mutation in children with pulmonary interstitial disease. Methods: In this retrospective study, the clinical data, outcomes and influencing factors of 7 cases of SFTPC gene 218 site mutations in infants with interstitial lung disease in three hospitals from January 2013 to December 2016 were analyzed. Results: Seven cases were full-term children, 4 cases had the onset within 3 months after birth, 2 cases after 1 year old, 1 case within 3 months to 1 year, clinical manifestations of these cases were cough, shortness of breath, dyspnea, and limited growth and development, could not maintain life without additional oxygen supplementation, blood gas analysis showed hypoxemia, 4 cases had clubbing. Chest CT showed diffuse ground glass-like change in both lungs. Three cases were positive for cytomegalovirus (CMV)-IgM or CMV-DNA. The mutations in 7 cases were exon 3, 5 of which were SFTPC gene c.218T>C, p.lle73Thr (heterozygous mutation), and 2 cases were SFTPC gene c.218T>A, p.lle73Asn (homozygous mutation), 1 case combined with ABCA3 gene mutations. Four patients were treated with prednisone alone, one with prednisone plus hydroxychloroquine, and two with symptomatic treatment. Three patients died, 3 patients improved, and 1 patient was lost to follow-up. Conclusions: The severity and prognosis of the children with SP-C 218 site mutation may be affected by many factors. Some children who received glucocorticoid alone do not have a good response.