Clinical features and chest CT findings of Chlamydia pneumoniae pneumonia

Objective: pneumonia, as confirmed by metagenomic next-generation sequencing (mNGS). Methods: pneumonia by mNGS at our hospital between August 2022 and August 2025. Results: Of the 42 patients, 25 (59.5%) presented with fever, 26 (61.9%) with sore throat, 30 (71.4%) with cough, 27 (64.3%) with expectoration, 11 (26.2%) with myalgia, 10 (23.8%) with general fatigue, and 10 (23.8%) with neurological symptoms such as headache and dizziness. Laboratory tests revealed that 12 patients (28.6%) showed a mild increase in white blood cell count, 10 (23.8%) had elevated neutrophil counts, 21 (50.0%) exhibited elevated C-reactive protein (CRP) levels, and 6 (14.3%) had CRP levels exceeding 100 mg/L. In the early stage, chest CT demonstrated a lobular pneumonia pattern in 16 patients (55.2%), involvement of a single lung lobe in 20 (69.0%), predominant lower-lung distribution in 19 (65.5%), and a nodular-patchy pattern in 8 patients (27.6%) with a nodular-patchy pattern. The main accompanying features included a halo sign in 25 patients (86.2%), centrilobular nodules in 23 (79.3%), and bronchial wall thickening in 20 (69.0%). In the mid-to-late stage, chest CT revealed a lobular pneumonia pattern in 23 patients (76.7%), single-lobe involvement in 23 (76.7%), and predominant lower-lung distribution in 20 (66.7%). The major concomitant features were a halo sign in 21 patients (70.0%), centrilobular nodules in 20 (66.7%), and bronchial wall thickening in 24 (80.0%). Conclusion: pneumonia are predominantly characterized by a lobular pneumonia pattern, lower-lobe distribution, and associated features such as bronchial wall thickening, centrilobular nodules, and a peripheral halo sign. Certain imaging differences exist between early and middle-to-late stages, with the nodular-patchy pattern potentially representing an ultra-early imaging marker, which may provide clues for early clinical intervention.