Characteristics and Outcome of Severe Mycoplasma pneumoniae Pneumonia Admitted to PICU in Shanghai: A Retrospective Cohort Study

OBJECTIVES: We aimed to describe the characteristics and outcome in children with severe Mycoplasma pneumoniae pneumonia in a Chinese PICU. DESIGN: A retrospective observational study from 2017 to 2019. SETTING: A 36-bed university tertiary PICU at Shanghai Children’s Hospital. PATIENTS: Patients admitted to a tertiary PICU 29 days to 18 years old screened for laboratory-confirmed severe M. pneumoniae pneumonia. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Descriptive analysis of baseline characteristics for patients included hospital mortality, organ dysfunctions, use of mechanical ventilation, continuous renal replacement therapy, and/or extracorporeal membrane oxygenation. A total of 817 children with severe pneumonia were admitted to PICU, and 203 of 817 cases (24.8%) with severe M. pneumoniae pneumonia were included in this study. The median age was 41 months (interquartile range, 20–67 mo), of which 77.3% (157/203) were younger than 6 years old. Among 163 patients with the test for macrolide resistance, 90.2% cases (147/163) were macrolide-resistant M. pneumoniae. Severe M. pneumoniae pneumonia-associated organ dysfunction included acute respiratory failure (203 cases, 100%), followed by cardiovascular disorder (79/203, 38.9%), gastrointestinal dysfunction (24/203, 11.8%). The main complications were pleural effusion (79/203, 38.9%), capillary leak syndrome (58/203, 28.6%), and plastic bronchitis (20/203, 9.9%). All patients needed respiratory support, including 64.5% patients (131/203) who received mechanical ventilation and 35.5% patients (72/203) who received high-flow nasal oxygen. Twenty-five patients (12.3%) treated with continuous renal replacement therapy and nine cases (4.4%) received extracorporeal membrane oxygenation. The case fatality rate was 3.9% (8/203). Furthermore, cardiovascular dysfunction, liver injury, or multiple organ dysfunction syndrome were associated with longer mechanical ventilation duration, delayed PICU discharge, and high hospital mortality. Coinfection was a risk factor of delayed PICU discharge. CONCLUSIONS: Children with severe M. pneumoniae pneumonia mainly occur under the age of 6 years, showing a high proportion of extrapulmonary organ dysfunction and macrolide resistances. Extrapulmonary organ dysfunction and coinfection are associated with worse outcomes. The overall mortality is relatively low after treated with appreciate antibiotics, respiratory support, and extracorporeal life support.