Value of Lung Ultrasonography in the Diagnosis and Outcome Prediction of Pediatric Community-Acquired Pneumonia with Necrotizing Change

Abstract

Background: Lung ultrasonography has been advocated in diagnosing pediatric community-acquired pneumonia. However, its function in identifying necrotizing pneumonia, a complication, has not been explored. This study investigated the value of lung ultrasonography in diagnosing pediatric necrotizing pneumonia and its role in predicting clinical outcomes.

Methods: We retrospectively reviewed 236 children with community-acquired pneumonia who were evaluated using lung ultrasonography within 2-3 days after admission. The ultrasonographic features assessed included lung perfusion, the presence of hypoechoic lesions, and the amount of pleural effusion. Chest computed tomography was also performed in 96 patients as clinically indicated. Detailed records of clinical information were obtained.

Results: Our results showed a high correlation between the degree of impaired perfusion in ultrasonography and the severity of necrosis in computed tomography (r = 0.704). The degree of impaired perfusion can favorably be used to predict massive necrosis in computed tomography (area under the receiver operating characteristic curve, 0.908). The characteristics of impaired perfusion and hypoechoic lesions in ultrasonography were associated with an increased risk of pneumatocele formation (odds ratio (OR), 10.11; 95% CI, 2.95-34.64) and the subsequent requirement for surgical lung resection (OR, 8.28; 95% CI, 1.86-36.93). Furthermore, a longer hospital stay would be expected if moderate-to-massive pleural effusion was observed in addition to impaired perfusion in ultrasonography (OR, 3.08; 95% CI, 1.15-8.29).

Conclusion: Lung ultrasonography is favorably correlated with chest computed tomography in the diagnosis of necrotizing pneumonia, especially regarding massive necrosis of the lung. Because it is a simple and reliable imaging tool that is valuable in predicting clinical outcomes, we suggest that ultrasonography be applied as a surrogate for computed tomography for the early detection of severe necrotizing pneumonia in children.

Fig 1. Ultrasonographic grading of pneumonia with necrotizing changes and flow chart of ultrasonograhic assessment.

(A) Hypoechoic lesions (HLs), rough-contoured heterogeneously hypoechoic areas in the consolidated lung, are indicated with arrows. Perfusion within the consolidated lung was assessed according to vascularity by using color Doppler. Normal, decreased, and poor perfusion are designated with P0, P1, and P2. (B) Step-by-step flow chart of ultrasonographic assessment.

Fig 2. Computed tomographic grading of pneumonia with necrotizing changes.

Severity of lung necrosis was measured on the basis of the absence of contrast uptake in computed tomography. Necrotic areas that were 0%, less than 30%, between 30 and 80%, and more than 80% were further categorized into no (N0), mild (N1), moderate (N2), and massive (N3) necrosis.

Fig 3. Spearman correlation between lung ultrasonography and computed tomography findings.

Fig 4. Receiver operating curves exhibiting impaired perfusion as a predictor of the varying severity of necrosis.

N1 + N2 + N3 = minimal-to-massive necrosis; N2 + N3 = moderate-to-massive necrosis; N3 = massive necrosis.