EC Pulmonology and Respiratory Medicine

Background: Pneumonia is a leading infectious cause of death in children under 5 years, with the greatest burden in developing countries. It is mainly diagnosed clinically using the WHO standard algorithm. Chest X-ray (CXR) which is the primary imaging modality used for the evaluation of pneumonia in children is usually reserved for severe or complicated cases of pneumonia. There is enough evidence to support chest ultrasound (CUS) as an alternative or adjunct to CXR in diagnosing community acquired pneumonia (CAP) in children. In this study we assessed the diagnostic performance of CUS in diagnosing pneumonia and the clinical correlates of radiological diagnosis of pneumonia in pediatric patients at Mulago National Referral Hospital.

Methods: We conducted a cross-sectional study, and enrolled 280 children below 13 years (age limit 2 months and 12 years), admitted with a clinical suspicion of pneumonia at acute care unit (ACU) of Mulago National Referral Hospital between January and June 2018. A clinical assessment, chest X-ray and chest ultrasound within 24hrs of admission were done on each child. Findings of CUS were compared to the composite reference standard of clinical findings plus CXR findings (final clinical diagnosis) was used to establish accuracy of CUS in diagnosing pneumonia. Logistic regression models were fitted to establish correlates of radiological diagnosis of pneumonia.

Results: Of the 280 enrolled, 252 children had complete data for analysis. Participants were predominantly < 24 months of age (68.6%) and slightly more males (52%). Overall, 81.3% had pneumonia clinically. CUS and CXR-based pneumonia prevalence was 64.7% and 37.7% respectively. Using final clinical diagnosis as reference, the accuracy was 71%. The sensitivity and specificity of CUS was 72% (95% CI [65 - 78]) and 67% (95% CI [52 - 81]), respectively. The area under receiver operating curve (ROC) of 0.7 (95% CI [0.62 - 0.77]). Significant correlates of CUS-based pneumonia diagnosis were: cough, OR = 3.9; [95%CI; 1.19 - 9.62], p = 0.022, and low oxygen saturation, OR = 1.9; [95% CI: 1.05 - 3.33), p = 0.035. While for CXR-based pneumonia, it was only low oxygen saturation, OR = 1.9 [95% CI: 1.07 - 3.26], p = 0.028.

Conclusion: Chest ultrasound has a good sensitivity and could be useful as a screening tool or/and an add-on diagnostic tool to CXR to diagnose pediatric pneumonia. Cough and hypoxia are good correlates to CUS-based pneumonia diagnosis in children with clinical suspicion of pneumonia.

Keywords: Pneumonia; Community Acquired Pneumonia; Paediatrics; Chest Ultrasound; Chest Radiography

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