Advanced stage: Chest CT mainly showed that the scope of the lesion expanded and the density increased, which could involve multiple lobes of both lungs and distributed in multiple places. Ground‐glass opacities and consolidation coexist and may be accompanied by interlobular septal thickening, fibrosis lesions, or air bronchogram signs (Figure 1B).
Critical stage: In the case of further development of the lesion, the chest CT showed that the consolidation lesions were diffuse and involved both lungs, presenting as a "white lung" change, accompanied by air bronchogram sign. The lesion density was heterogeneous, accompanied by ground‐glass opacities and pleural thickening (Figure 1C).
Recovery stage: After treatment, a chest CT follow‐up was obtained in six cases. Lesions were completely absorbed in two cases (2/20, 10%) (Figures 2A and 2D), consolidations turned into ground‐glass opacities and gradually decreased in three cases (3/20, 15%) (Figures 2B and 2E), and residual fiber strip remained in three cases (3/20, 15%) (Figures 2C and 2F).
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A, Male, 3 years old. On admission, chest CT showed consolidation in the posterior segment of the upper lobe of the left lung with a surrounded halo sign. B, Female, 8 years old. On admission, chest CT showed patchy consolidation with halo sign in the basal segment of the inferior lobe of the right lung, and ground‐glass opacities in the inferior lobe of the left lung. C, Male, 14 years old. On admission, chest CT showed consolidation with halo sign in the lingular segment of the left lung, and fibrous cords in both lungs. D, The same patient of (A), 11 days after admission, chest CT showed that the consolidation in the posterior segment of the upper lobe of the left lung was disappeared. E, The same patient of (B), 4 days after admission, chest CT showed shrunken lesions with lower density in the inferior lobes of both lungs. F, The same patient of (C), 3 days after admission, chest CT showed a contraction of consolidation in lingular segment of the left lung, the disappearance of halo sign, and fibrous cords left in both lungs. CT, computed tomography
All the patients had been treated in the isolation ward of Wuhan Children's Hospital. Eighteen patients were cured and discharged with an average stay of 12.9 days (8‐20 days). Two asymptomatic neonates were still under observation because of positive results from the pharyngeal swab COVID‐19 nucleic acid test, with negative CT findings.
COVID‐19 viral pneumonia is an acute infectious respiratory disease caused by a novel coronavirus. By the beginning of February 2020, nearly 30 000 cases had been confirmed nationwide, while the actual number would be larger.5 The virus can be transmitted by an infected person or an asymptomatic carrier and is a highly contagious disease. Respiratory droplets are the main route of transmission, but can also be transmitted by contact and digestive tract.6 The incubation period is about 1 to 14 days, and is supposed could be up to 24 days. Crowds are generally susceptible to COVID‐19. Most of the cases are mild, but the elderly or those with underlying diseases are more likely to develop to severe stage.7 The lack of children samples in the previously reported studies may be related to the children staying at home during the Spring Festival holiday and having less contact with the source of infection.
The clinical manifestations of children patients are similar to those of adults, such as fever and cough. A few children have diarrhea and runny nose, but the overall symptoms are relatively mild. Thirteen pediatric patients, including three neonates, had an identified history of close contact with COVID‐19 diagnosed family members, who were undergone the COVID‐19 RNA detection. Although the results in three neonates were positive, no lesion was found on chest CT, repeated COVID‐19 RNA detection should be carried out for excluding the possibility of a contaminated sample and other reasons. As no evidence of vertical transmission has been confirmed in the previous study,8 close contacts may be the possible explanation for the positive result in our study. Remarkably, 7 of 20 patients had a previous history of congenital or acquired diseases, which may indicate that children with underlying diseases may be more susceptible to COVID‐19 infection. Overall, pediatric patients generally have a good prognosis with an average hospital stay of 12.9 days.
PCT is a marker for bacterial infection which could be induced by bacteriotoxin but suppressed by interferon.9 It is worth noting that the PCT was elevated in 80% cases in this study, no matter coinfection evidence existed or not, which is not common in adult patients. It may suggest that routine antibacterial treatment should be considered in pediatric patients, as the coinfection was common in our cases (40%).
In most cases of this study, abnormal laboratory results may prompt clinicians to further screen the nucleic acid detection of COVID‐19 virus. In a clinical setting, pharyngeal swab COVID‐19 virus nucleic acid detection is an important basis for diagnosis. However, due to the limitation of sampling materials, especially in the early stage of the disease, the positive rate is relatively low. Therefore, early diagnosis is of great significance for further rational management and clinical treatment of children. Moreover, since most of the pediatric patients are mild cases, plain chest X‐ray often fails to show the lesions or the detailed features, leading to misdiagnosis or missed diagnosis. Therefore, early chest CT examination is very necessary. In some pediatric patients with a negative nucleic acid of COVID‐19 virus, we managed them as suspected patients according to the typical lesions shown on chest CT, which could provide evidence not only for early treatment to the children but also for effectively isolating the source of infection.
Chest CT findings in children were similar to those in adults, and most of them were mild cases.10, 11 The typical manifestations were unilateral or bilateral subpleural ground‐glass opacities, and consolidations with surrounding halo sign. As consolidations with surrounding halo sign account for up to 50% cases, they should be considered as typical signs in pediatric patients. Pleural effusion was not seen. The absorption of lesions on chest CT lagged behind clinical symptoms and nucleic acid detection. Lesions could be still visible on chest CT when two consecutive nucleic acid tests were negative. As for the normal findings in three neonates with a positive nucleic acid test, whether it was due to the influence of the delivery process on sampling or the specific CT manifestations for neonates, more samples are needed for further confirmation.
The CT imaging of COVID‐19 infection should be differentiated with other virus pneumonias, such as influenza virus, parainfluenza virus, respiratory syncytial virus, and adenovirus.12 Adenovirus pneumonia lesions had higher density, more consolidations, and fewer subpleural lesions. Respiratory syncytial virus and parainfluenza virus pneumonia lesions were mostly distributed along the bronchial tree with a thickened bronchial wall. Influenza viruses could cause grid‐like changes in the lungs. In addition, it should be differentiated from bacterial pneumonia, mycoplasma pneumonia, and chlamydia pneumonia, and the density of pneumonia lesions caused by the latter pathogens is relatively higher. However, chest CT manifestations of pneumonia caused by different pathogens overlap, and COVID‐19 pneumonia can be superimposed with pneumonia caused by other types of pathogens, presenting more serious and complex imaging manifestations, so epidemiological and etiological examination should be combined.
In conclusion, COVID‐19 virus pneumonia in children is mainly mild, and chest CT can present characteristic changes of subpleural ground‐glass opacities and consolidations with surrounding halo, which is an effective means for follow up and evaluating the changes of lung lesions. In the case that the positive rate of COVID‐19 nucleic acid test from pharyngeal swab samples is not high, the early detection of lesions by CT is conducive to reasonable management and early treatment for pediatric patients. However, the diagnosis of COVID‐19 pneumonia by CT imaging alone is not sufficient enough, especially in the case of coinfection with other pathogens. Therefore, early chest CT screening and timely follow‐up, combined with corresponding pathogen detection, is a feasible clinical protocol in children.
CONFLICT OF INTERESTS
The authors declare that there are no conflict of interests.