Correlation between clinical features, high-resolution computed tomography findings, and a visual scoring system in patients with pneumonia due to Mycoplasma pneumoniae

Background: Mycoplasma pneumoniae (MP) is the primary cause of community-acquired pneumonia. We aimed to evaluate the correlation between clinical features, with special reference to hypoxemia and the total affected area obtained using high-resolution computed tomography (HRCT). Methods: Medical records of MP pneumonia patients > 15 years of age at Kyorin University Hospital between January 2006 and November 2013 were reviewed retrospectively and compared to patients with Streptococcus pneumoniae pneumonia, diagnosed between January 2013 and September 2014. Results: We identified 65 and 32 patients with MP- and S. pneumoniae pneumonia, respectively. HRCT data were available for 42 and 32 patients with MP- and S. pneumoniae pneumonia, respectively. Data were available for all hypoxemic patients. Hypoxemia was significantly higher in patients with S. pneumoniae (14/32, p = 0.008) than those with MP (5/ 39). Total visual score on HRCT correlated significantly with hypoxemia in both groups, but showed significantly higher scores with MP- than with S pneumoniae pneumonia in hypoxemic patients. MP pneumonia showed significant positive correlation between the total visual score and serum inflammatory markers (C-reaction protein [r = 0.43, p = 0.025] and lactate dehydrogenase [r = 0.466, p = 0.016]). In both groups, individual scores in the middle and lower lung fields were significantly higher than in the upper field, suggesting zonal predominance. Conclusions: This study provides the first evidence that the total affected area on lung HRCT was more with MP compared to S. pneumoniae pneumonia in hypoxemic patients and positively correlated with hypoxemia and serum inflammatory markers. (C) 2018 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.