Clinical presentation and CT features in pediatric patients with COVID ‐ 19 infection

Background The aim of this study includes to discuss the clinical, laboratory, and chest computed tomography (CT) in pediatric patients with 2019 novel coronavirus (COVID-19) infection. Material and Methods The clinical, laboratory, and chest CT features of 17 pediatric inpatients with COVID-19 infection con�rmed by pharyngeal swab COVID ‐ 19 polymerase chain reaction(PCR). All clinical and laboratory data have been recorded and analyzed during march-february 2021. Chest CT have been performed to all Covid 19 PCR con�rmed patients and radiologicall view have been noted. Results Seventeen pediatric patients with a history of close contact with COVID-19 diagnosed family members included to the study. Fever (10/17, 58%) and cough (13/17, 76%) were the most common symptoms. For laboratory �ndings, c reactive protein elevation (15/17, 88%) seem to be the most �nding. A total of 4 patients presented with unilateral pulmonary lesions (4/17, 23%), 9 with bilateral pulmonary lesions (9/17, 52%) and 13 cases showed bilateral diffuse covid pattern on chest CT (13/17, 76%). Non-spesic consolidation with was observed in 8 patients (8/17, 47%), ground ‐ glass opacities were observed in 11 patients (11/17, 64%), nodules were observed in 7 patients (7/17, 41%), and tiny nodules were observed in 2 patients (2/17, 11%).


Introduction
A pneumonia epidemic broke out in Wuhan and then spread to other Chinese cities and several countries resectively in december 2019.A new type of coronavirus announced by the Chinese Center for Disease Control and Prevention on January 7, 2020 [1].Finally; on february 11, 2020, the International Committee on Taxonomy of Viruses (ICTV) proposed to name the new virus SARS-CoV-2 and the WHO named the disease caused by SARS-CoV-2 infection COVID-19 [2,3].As of today, 8 months after the onset of epidemic, China's domestic COVID-19 epidemic has been well controlled contravarsiouly the epidemic spreaded to many countries worldwide [4].Lately; the virus outbreak in countries of Europe and America are severely affected at this moment, which means that COVID-19 has evolved from an epidemic to pandemic.From the early days of the outbreak to this moment; the disease showed that there were to less cases in children under the age of 15 [5].Soon afterwards, laboratory-diagnosed cases from all over China through January 29, 2020, indicated that 0.9% of patients were aged below 15 years, which means that COVID-19 can be spread within the whole age spectrum [6].
In this study; clinical and imaging features of pediatric patients with COVID-19 infection were presented in a series of 17 cases who have been identi ed by the pharyngeal swab COVID-19 nucleic acid test.Clinical data including demography information, contact history, previous history, clinical symptoms, laboratory ndings, and coinfection which de ned as a concurrent infection of a patient with two or more pathogens simultaneously.

Seventeen
The chest CT were obtained from all subjects, as the plain chest X-ray cannot exclude the existence of pulmonary lesions, especially for the patients without symptoms and mild cases.For all the patients, noncontrast chest CT studies were performed on SOMATOM De niton AS 128 unit (Siemens medical system; Siemens, Germany) with the following parameters: 12 0 kV, 100 to 150 mA, 0.6-mm collimation, and 1:1 pitch.The scanning range covered from lung apex to diaphragm on axial plane taken under free breathing with the patients in the supine position.CT images were reconstructed with 3 or 4 mm collimation with a standard algorithm and then sent to the picture archiving and communication system (PACS) for analyzing.CT images were evaluated using a lung window with a window level of − 600 HU a window width of 1500 HU, and the soft-tissue window with a window level of 40 HU and window width of 300 HU.All the images were stored in PACS and reviewed by experienced pediatric radiologists.The CT features were evaluated as follows: (a) ground-glass opacities, (b) consolidations with surrounding halo sign, (c) nodules, (d) ne mesh shadow, (e) pleural effusion, (f) lymphadenopathy, (g) unilateral or bilateral, (h) subpleural or nonsubpleural, and (i) residual ber strips.Pharyngeal swab samples of all the subjects in this group were collected, and the COVID-19 RNA was identi ed by a reverse transcriptionpolymerase chain reaction.
The protocol for this retrospective study was approved by the Ethics Committee of Istinye University Medical Park GOP Hospital and the written informed consent was waived for emerging infectious diseases.

Results
Seventeen pediatric patients with a history of close contact with COVID-19 diagnosed family members included to the study.Fever (10/17, 58%) and cough (13/17, 76%) were the most common symptoms.The clinical features of pediatric patients with COVID-19 infection were displayed in Table 1.
Table 1 The clinical features of pediatric patients with COVID- For laboratory ndings, c reactive protein elevation (15/17, 88%) seem to be the most nding.The laboratory features of pediatric patients with COVID-19 infection were displayed in Table 2.The CT imagining features of pediatric patients with COVID-19 infection were displayed in Table 3 For CT imaging ndings; The lesion density was heterogeneous, accompanied by ground-glass opacities and pleural thickening.(Fig. 1A) 12 year old girl.After 5 days, thE opacity in ground glass density in the posterior basilar segment of the right lower lobe increased in size.(Fig. 1B).There were no other accompanying thoracic ndings in CT imaging of this 12 years old girl patient.
In an other 16 year old male patient, the rst CT imaging nding was observed with an increase in subpleural ground glass density in the left lower lobe posterior segment.(Fig. 2A) When viewed immediately, ie 2 to 4 days later, the density began to decrease and the contour clarity began to disappear.(Fig. 2C) The lesion size and density increased signi cantly 6 days after this diagnosis.(Fig. 2C) After 14 days (24 days after initial detection) taken for the 4th time, the lung parenchyma is observed normally.(Fig. 2D) to date records, while the actual number would be larger with nonco med asymptmatic cases.
[8] The virus is a highly contagious disease andcan be transmitted by an infected person or an asymptomatic carrier through respiratory droplets.Respiratory droplets are the main route of transmission, but can also be transmitted by contact and digestive tract.[9] After contact to infected person; The incubation period is about 1 to 14 days, and is supposed could be up to 24 days.Even most of the cases are mild, especially people over 60 years old or those with underlying diseases are more likely to develop the severe disease of lower repiraturary system involvement.[10] 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.Its think to be that the COvid-19 infection have a mild and weak clinical progress in childeren.Conversly to this data; in this study we presented 17 cases those all are under 17 years old with 3 of them under 2 years old cases of Covid-19 infection with severe diseases.
In previous literatüre Chest CT ndings in children were similar to those in adults, and most of them were mild cases.[11,12] In our study; the typical manifestations were unilateral or bilateral subpleural groundglass opacities, and consolidations with surrounding halo sign.As bilatarelly consolidations of lungs sign account for up to 70% cases, they should be considered as typical signs in pediatric patients.Pleural effusion was seen in 4 cases.In Wei and et al study; the data for pleural effusion account zero.[13] Lesions could be still visible on chest CT when two consecutive nucleic acid tests were negative.The CT imaging of COVID-19 infection should be differentiated with other virus pneumonias, such as respiratory syncytial virus, in uenza virus, parain uenza virus, and adenovirus with its spesi c radiological signs.
[14] In addition, it should be differentiated from atypic bacterial pneumonia such as mycoplasma pneumonia and chlamydia pneumonia.However, multiple agents can overlap chest CT manifestations of pneumonia caused by COVID-19 presenting more serious and complex imaging manifestations which could not be diagnostic, so epidemiological and etiological examination should be combined to make the nal decision.The CT manifestations of COVID-19 in pediatric patients are diverse and lack speci city.Some mild pediatric patients with COVID-19 show [18,19].
In pulmunary involvement cases; focal unilateral or bilateral diffuse, subpleural lesions, nonspesi c consalidation, ground-glass opaci cation and nodules are the most presentations.
Pediatric patients with COVID-19 tend to present less lobular involvement with an increase in subpleural ground glass density in the left lower lobe posterior segments (Fig. 1a,2a).Additionally;some other ndings like nodular ground-glass opaci cation consolidation, consolidation with ground-glass opaci cation and interlobular septal thickening can also be observed in the pediatric patients [20].All radiological ndings have been summarized in Table 3.
Overall, rarely in pediatric cases, bilateral diffuse lung consolidation can occur and is called as "white lung" [16].In resolving stage, lung lesions will be completely resolved or only remain minimal linear opacities (Fig. 2d,3d).In some cases either can be a presentation of similiar to those other viral agents With patchy opacity along the bronchial vasculer structure manisfasting as bronchopneumonia.[16] Case differantial diagnosis should be more carefully done while pediatric patients have de nite epidemiological history but atypical CT ndings.Xia et al reported, underlying coinfection is very common in pediatric patients (9 of 20, 45%), Pleural effusion was reported in several pediatric patients [21].
Even the gold standart is nucleic acid detection in diagnosis of COVİD-19, in suspecious cases those initial RT-PCR results show negative, chest CT may be supporttive for diagnosis and management especially in pediatric age group.Additionally Chest Ct can suggest the healing and resolve ndings of lung involvement regarding the disease severness and follow up options.In this study the chest ct ndings in 14th day of follow up have been completely recovered.(Fig. 2d,3d).Sure the nucleic acid com rmation test negativity can be used in follow up; unfourtanetly it will not suggest any idea in those cases with pulmunary symptoms in childhood.

Conclusions Figures
12 year old girl.It was observed that opacity in ground glass density in the posterior basilar segment of the right lower lobe increased in size after 5 days.There were no other accompanying thoracic ndings.
Figure 2 16-year-old male.The rst imaging nding was observed with an increase in subpleural ground glass density in the left lower lobe posterior segment.(2a ) When looked at once, that is, after 2 to 4 days, density began to decrease and contour clarity began to disappear.(2b) The lesion size and density increased signi cantly 6 days after this diagnosis.(2c ) After 14 days (24 days after the rst detection) taken for the 4th time, the lung parenchyma is observed normally.(2d ) pediatric inpatients with COVID-19 infection con rmed by pharyngeal swab COVID-19 nucleic acid test from march to february 2021 in our university hospital were included in this study.All the patients are in accordance to the Diagnosis and Treatment Protocol for COVID-19 by the National Health Commission.
. VRT (volumetric rendering technique) images of the same patient were similar in discussion.(Figs.3A, 3B, 3C, 3D) The chest VRT image is more valuable to see ground glass consolidation and other signs of COVID-19 pneumonia in children.This is the rst report in the literature discussing VRT in this age group of COVID-19 pneumonia.
COVID-19 viral pneumonia is an acute infectious respiratory disease caused by a coronavirus subtype SARS-CoV-2.From december 2019 to this moment, 24.355.000total com rmed cases, 830.155 deaths and 16.889.000recovered cases had been con rmed worldwide as WHO (World Health Organization) up

Table 3
[15,CT i17]ining features of pediatric patients with COVID-19 infection Recently; only a few studies have conducted on chest CT signs of COVID-19 in children age group.[15,16,17]Evennormal ndings on chest CT; some of pediatric patients manifest a severe clinical disease of COVID-19 pneumonia.