[Clinical characteristics and predictive factors of refractory Mycoplasma pneumoniae pneumonia].

Objective: To investigate clinical characteristics and predictive factors of refractory Mycoplasma pneumoniae pneumonia (RMPP) in children so as to recognize and treat the disease earlier.

Method: The data including febrile time, inflammatory markers (WBC, neutrophil, CRP) and radiological features of 213 children hospitalized with Mycoplasma pneumoniae pneumonia (MPP) (72 with refractory MPP and 141 with mild MPP were retrospectively analyzed). The primary diagnostic criteria of refractory MPP: the patient's condition still deteriorates after treatment with macrolides for more than 5 days. The independent variables which had significant difference in univariate analysis was analyzed by multivariate logistic regression analysis. The predictive criteria of RMPP were further applied in 100 other patients prospectively. Kappa test was used to evaluate the accuracy rate.

Result: Refractory MPP patients: febrile time was more than 10 days, white blood cell (WBC) count was (3.8 - 18.5)×10(9)/L in peripheral blood routine test, CRP was 38 mg/L - > 160 mg/L, large lobar consolidation with high density (> 2/3 pulmonary lobe, CT value 40 - 50 HU, without air bronchogram). Mild MPP patients: febrile time was less than 10 days, CRP was often less than 40 mg/L. Independent risk factors for RMPP were febrile time, CRP, large consolidation area with high density in lungs with or without pleural effusion (OR = 1.586, P = 0.017; OR = 4.344, P = 0.001; OR = 2.660, P = 0.012), CT value 40 - 50 HU which were demonstrated by logistic regression analysis. The specificity, sensitivity and Youden index for this diagnostic test were respectively 0.96, 0.94 and 0.90 at a CRP cut off of 40 mg/L. The sensitivity, specificity, and Kappa value for the above criteria to diagnose RMPP were respectively 0.96, 0.94 and 0.9.

Conclusion: The predictive factors for RMPP are febrile time (> 10 days), CRP (> 40 mg/L), large lobar consolidation with high density (> 2/3 pulmonary lobe, CT value > 40 HU with or without pleural effusion) for the purpose of treating earlier.