Clinical features and chest CT findings of Chlamydia pneumoniae pneumonia.

OBJECTIVE

This study aimed to investigate the clinical features and chest computed tomography (CT) findings in 42 patients with Chlamydia pneumoniae pneumonia, as confirmed by metagenomic next-generation sequencing (mNGS).

METHODS

We conducted a retrospective analysis of clinical data and chest CT findings (both at disease onset and within 1 month thereafter) in 42 patients diagnosed with Chlamydia pneumoniae 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

Chest CT findings of Chlamydia pneumoniae 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.