[Clinical features of <i>Chlamydia pneumoniae</i> pneumonia in 10 children].

<b>Objective:</b> To summarize the clinical features of <i>Chlamydia pneumoniae</i> pneumonia (CPP) in children. <b>Methods:</b> Case series study. Clinical data of 10 children with CPP hospitalized in Department No.2 of Respiratory Medicine of Beijing Children's Hospital, Capital Medical University from January 2019 to August 2024 were retrospectively collected, including general information, clinical manifestations, chest imaging, laboratory examination and treatment. The clinical features and prognosis were summarized. <b>Results:</b> Among the 10 children with CPP, 7 were male and 3 were female. The age of onset was 11.2 (10.3, 13.1) years. The course were 17 (7, 23) days. Cough occurred in 9 cases with wet cough in 7 cases, while moderate and high fever occurred in 6 cases. Besides, chest pain occurred in 4 cases, rash and hemoptysis occurred in 1 case respectively. High density mass shadow was found in 7 cases chest CT imaging, accompanied by air bronchogram sign, surrounded by halo sign, 6 cases of which were distributed under the pleura, while patchy consolidation in the remaining 3 cases. Pulmonary embolism was present in 2 cases. Bilateral lung involvement was found in 3 cases and unilateral lung involvement in 7 cases. The white blood cell count was 10.21 (7.45, 11.64)×10⁹/L and the proportion of neutrophils was 0.69 (0.63, 0.71). C-reactive protein increased in 7 cases, with the level of 33 (16, 77) mg/L. D-dimer increased slightly in 3 cases (0.393, 0.396, 0.739 mg/L). Serum <i>Chlamydia pneumoniae</i>-IgM antibody test was positive in 6 cases. <i>Chlamydia pneumoniae</i> nucleic acid test by bronchoalveolar lavage fluid (BALF) next-generation sequencing was positive in 6 cases. Both serum IgM antibody and BALF nucleic acid tests were positive in 2 cases. Azithromycin alone was used in 5 cases, while glucocorticoid was added in 1 case. Due to poor response to azithromycin in 4 cases, doxycycline was replaced in 3 cases and minocycline was replaced in 1 case, while glucocorticoid was added in 2 cases. Moxifloxacin combined with glucocorticoid therapy was adopted in 1 case with long course after the poor response to azithromycin and doxycycline. All patients were cured finally. <b>Conclusions:</b> CPP mostly occurs in elderly children. The main clinical manifestations include cough, fever and chest pain. The common chest imaging feature is subpleural high-density mass shadow with halo sign. Pulmonary embolism is present in a few cases. Nucleic acid detection and (or) serology is helpful for etiological diagnosis. Some cases need glucocorticoid therapy.