Lung ultrasound compared to chest X-ray for the diagnosis of CAP in children

Background: community-acquired pneumonia (CAP) represents one of the most common infectious diseases among children. Diagnosis of CAP is mainly clinical. Chest X-ray (CXR) remains the gold standard for the diagnosis in severe or controversial conditions. Recently, some authors focused on the application of ultrasound in lung diseases, but the role of Lung Ultrasound in the diagnosis of CAP is still debated. We aimed to study the concordance between LUS and CXR in evaluating specific signs of CAP. As a secondary aim, we sought to determine LUS sensitivity and specificity in CAP diagnosis compared to CXR. Finally, we evaluated the role of LUS during the follow-up. Methods: We enrolled 68 children (<16 years old) hospitalized from October 2018 to September 2019 with a clinical and radiological diagnosis of CAP (cases, N=41), or with no respiratory diseases (controls, N=27), in whom a CXR was performed for clinical indication. All the children performed a LUS during hospitalization. The average time needed to perform LUS was 5-10 minutes for each child. 19/41 cases were re-evaluated by LUS and CXR 30 days after discharge. Results: LUS confirmed CAP diagnosis in 40/41 patients. Concordance between the two techniques was K=0.88 for the right lung and K=0.70 for the left lung. LUS showed a sensitivity of 97% and a specificity of 96% compared to CXR. At the follow-up, sensitivity raised to 100% while specificity was 94%. Conclusions: Our study showed a potential benefit of LUS compared to CXR in both the diagnosis and follow-up of CAP.