The value of lung ultrasound in diagnosing community-acquired pneumonia in tuberculosis endemic regions.

<bold>Introduction:</bold> Lung ultrasound (LUS) shows high accuracy in diagnosing community-acquired pneumonia (CAP) where tuberculosis (TB) is rare, but its value in high TB prevalence areas is unclear. This study aims to evaluate the diagnostic value of LUS in Vietnam, a TB-endemic region. <bold>Methods:</bold> A prospective study at Cho Ray Hospital, Vietnam, included adults with CAP symptoms (cough, pleuritic pain, sputum production, fever, and dyspnea), excluding those hospitalized ≥48 hours prior, pregnant, lactating, or COVID-19 positive. Two ultrasound-certified pulmonologists performed LUS within 24 hours of admission. Patients also underwent chest X-ray (CXR) within 24 hours. The study compared the diagnostic accuracy of LUS and CXR against discharge diagnoses by 2 pulmonary experts, with computed tomography (CT) scans serving as a secondary reference when available. LUS data was not made available to the diagnostic team. <bold>Results:</bold> Among 136 patients, the mean age was 62.35 ± 17.03 years, with 72.8% being male. LUS showed higher sensitivity (96%) compared to CXR (82.8%, p=0.002), while specificity was similar (LUS 64.9% vs CXR 54.1%, p=0.103). 93 patients had CT scan. Using CT as a secondary reference, LUS performance was similar to that based on discharge diagnoses, with a sensitivity of 95.8% and a specificity of 52.4%. TB accounted for over half of the false positives (7/13), affecting specificity. <bold>Conclusion:</bold> LUS offers a non-invasive, quick, bedside diagnostic tool with high accuracy for CAP. However, TB may have a sonographic presentation similar to pneumonia; this should be kept in mind when performing diagnostic ultrasound in regions with high TB prevalence.