Epidemiology and clinical features of segmental/lobar pattern Mycoplasma pneumoniae pneumonia: A ten-year retrospective clinical study.

Mycoplasma pneumoniae plays an important role in community-acquired pneumonia. However, epidemiological and clinical studies on the segmental/lobar pattern (S/L) radiographic-pathologic subtype of pediatric Mycoplasma pneumoniae pneumonia (MPP) are rare. The current study retrospectively analyzed the epidemiological and clinical characteristics of pediatric MPP patients. A total of 1,933 children with MPP received treatment at a single hospital between 2000 and 2009, of which 684 (35.4%) were diagnosed with S/L-MPP. The annual incidence of S/L-MPP in children with MPP increased throughout the duration of this study (from 6.4 to 59.6%, P<0.001), which was particularly evident after 2003. S/L-MPP was predominantly found in pre-school-aged children (4-6 years old; 56.6%). Compared with non-S/L-MPP, S/L-MPP was more closely associated with severe manifestations, including higher rates of fever (90.2 vs. 83.3%), pleural effusion (3.9 vs. 1.3%), extrapulmonary manifestations (26.2 vs. 21.2%), abnormal white blood cell counts (65.5 vs. 55.2%), abnormal C-reactive protein levels (30.9 vs. 23.7%) and bacterial co-infection (32.0 vs. 24.9%), as well as longer durations of fever (4.13±4.28 vs. 3.02±2.22 days) and hospitalization (12.70±4.54 vs. 9.22±5.12 days). Older S/L-MPP patients showed higher rates and longer durations of fever and cough; however, they also displayed a lower rate of extrapulmonary manifestations when compared with younger patients. In conclusion, the annual incidence of S/L-MPP has increased in recent years. Pre-school-aged children (4-6 years) with MPP are more likely to display a segmental/lobar pattern, which is associated with more severe clinical manifestations than other MPP infection patterns.