Early predictors of childhood Mycoplasma pneumoniae pneumonia associated with airway mucus plug

Abstract

Objective To investigate the early predictors of Mycoplasma pneumoniae pneumonia (MPP) in children with blockage of airway mucous plug. Methods Retrospective analysis was executed on the clinical data of 130 children, who were diagnosed as MPP and treated with fiberoptic bronchoscopy at the Department of Pediatrics, the First Hospital of Jilin University, from September 2016 to January 2017.The patients were divided into the mucus plug group (60 cases)and the control group(70 cases) according to the performance of flexible bronchoscopy.The general information, clinical manifestations, laboratory examination, radiological features, bronchofibroscopic findings and treatment were compared between 2 groups.The multiple Logistic regression analysis and receiver operating characteristic (ROC) curve were used for the single factor with clinical and statistical significance to identify the early predictors of the MPP with blockage of airway mucus plug. Results Compared with the control group, the fever peak [39.8 ℃(39.5 ℃, 40.0 ℃) vs. 39.5 ℃(39.0 ℃, 39.8 ℃)], the fever duration[(11.3±3.1) d vs.(7.8±2.4) d], hospitalization time[(13.5±3.8) d vs.(8.5±3.2) d], white blood cells (WBC)[(9.4±3.7)×109/L vs.(8.2±2.9)×109/L], the percentage of neutrophils (NE) (0.698±0.112 vs.0.623±0.119), C-reactive protein (CRP) [48.2 (19.8, 91.0) mg/L vs.12.4 (7.1, 25.4) mg/L], lactic dehydrogenase(LDH) [466.5(371.5, 639.0) U/L vs. 323.0(273.2, 376.8) U/L], the proportion of combined with pleural effusion(56.7% vs.17.1%), atelectasis(23.3% vs.7.1%), necrosis (16.7% vs.0)and involved lobes more than 2 (40.0% vs. 21.4%) were higher in the mucus plug group, and these indicators had significantly statistical differences(Z=-3.394, t=-6.957, -8.021, -2.046, -3.672, Z=-6.402, -6.433, χ2=22.074, 6.786, 12.639, 5.306, all P<0.05). The multiple Logistic regression analysis showed that the febrile time, CRP and LDH were independent predictors for the MPP with blockage of airway mucus plug.The ROC curve analysis showed that the cut-off values of the 3 predictors were febrile time≥9.5 d[area under curve (AUC)=0.810, 95% confidence interval(CI): 0.738-0.883], CRP≥30.4 mg/L(AUC=0.826, 95%CI: 0.757-0.895), and LDH≥343.5 U/L (AUC=0.828, 95%CI: 0.756-0.900). Conclusion The fever duration ≥9.5 d, increased CRP (≥30.4 mg/L), and increased serum LDH (≥343.5 U/L) can be applied as one of the early predictors for MPP in children with mucus plug. Key words: Mycoplasma pneumoniae pneumonia; Fiberoptic bronchoscope; Predictor; Mucus plug; Child