1. Introduction
In December 2019, an outbreak of COVID-19 began in Wuhan, China (1). COVID-19 is an acute respiratory infectious disease caused by a severe acute respiratory syndrome coronavirus (SARS-CoV-2) (2). This disease mainly presents with respiratory symptoms, but less than 10% of children with COVID-19 develop gastrointestinal symptoms such as diarrhea and vomiting (3). 
The chest computed tomography (CT) scan is used to diagnose respiratory tract manifestation in infected patients. The affected area appears as white lung, sub-pleural consolidations, and initial and pleural irregularities. Further, massive pleural effusion has been reported in an adults with COVID-19 (4, 5). In this study, one case of COVID-19 was reported in a child with pleural effusion.

2. Case Presentation
On April 13, 2020, a 7-year-old boy without a past medical history of a specific disease and medical drug use was presented to the Emergency Department of Be’sat Hospital in Sanandaj City, Iran, with seven days history of fever, abdominal pain, and non-bloody vomiting and diarrhea. The vomiting had begun after the onset of fever, and it was intermittent. In addition, he had suffered from two transient generalized urticarial lesions that disappeared after a few hours. 
Although the patient received outpatient treatment during these seven days, the symptoms did not improve over time. His primary vital signs included an elevated temperature of 39°C, a tachycardia of 120 beats per minute, a respiratory rate of 51 breaths per minute, and an oxygen saturation of 93%. Erythematous conjunctiva and generalized wheeze were detected in the left lung auscultation. The patient was transferred to the pediatric ward after stabilization, and antibiotic therapy with ceftriaxone was started. His preliminary laboratory results showed elevated C-reactive protein (Table 1).

The size of the liver was normal in abdominal ultrasound, and the spleen had a normal echo, but it represented a slight enlargement. Based on the results, the kidneys had normal size and echo, and numerous hypo-echoic lymph nodes were observed in the right para-umbilical region. Echocardiography was performed to rule out Kawasaki, and it was normal.
One day after hospitalization, the patient developed a dry cough and became tachypneic. Therefore, the chest x-ray (CXR) was performed, and the result was normal (Figure 1).

Nevertheless, the patient’s respiratory symptoms worsened during the following days, and gastrointestinal symptoms improved accordingly. Therefore, the CXR was performed again on the fourth day of hospitalization, and signs of pleural effusion in both lungs (with severity in the right lung) were evident (Figure 2).

Thus, a chest CT scan was requested, and several symptoms were observed, including patchy consolidation, ground-glass opacity (GGO), and bilateral pleural effusion with severity on the right side (Figure 3).

Therefore, a polymerase chain reaction (PCR) test of the nasopharyngeal sample was requested to rule out the COVID-19.
Nasopharyngeal PCR was positive for COVID-19; thus, the patient was transferred to the intensive care unit of COVID-19 patients on the fourth day of hospitalization. He underwent treatment with hydroxychloroquine, azithromycin, Kaletra (lopinavir/ritonavir), and one dose of intravenous immunoglobulin. Moreover, chest tubes were placed on both sides on the fifth day of hospitalization, and meropenem and vancomycin were added to his treatment.
The laboratory results of pleural fluid examinations showed transudative pleural effusions (Table 1)—nearly 400 mL of a clear fluid discharged from both sides.
The second chest CT scan on the eighth day of hospitalization demonstrated patchy infiltration on both sides, although bilateral pleural effusion disappeared, and chest tubes were removed accordingly (Figure 4).

On the 10th day of hospitalization, abdominal sonography was performed again, and the result was normal. The patient became symptom-free after 15 days of hospitalization and treatment and was discharged in a generally good condition.

3. Discussion
Severe acute respiratory syndrome COVID-19 can also involve the gastrointestinal tract. Like the respiratory mucosa, angiotensin-converting enzyme-2 receptor and trans-membrane serine protease 2 co-express in the gastrointestinal tract, which helps viral entry into the tissue (3).
Chest CT scan has a high sensitivity for the diagnosis of COVID-19 and may be considered a primary tool for diagnosing COVID-19 in epidemic areas (6). Adam et al. suggested that bilateral and peripheral ground-glass and consolidative pulmonary opacities in the chest CT scan are the hallmarks of COVID-19 (7). Likewise, Zhou S et al. reported that the identification of GGO and a single lesion on the initial CT scan suggested early-phase disease (8). Thus, patients with fever and cough symptoms and GGO lesions on chest CT scan, with a standard or decreased range of white blood cells and a history of epidemic exposure, are highly suspected of having COVID-19 (9). 
Lung ultrasound in COVID-19 patients revealed a different pattern of lung involvement. Vertical artifacts (70%), pleural irregularities (60%), white lung areas (10%), and sub-pleural consolidations (10%) were the main findings in patients with COVID-19, although there were no cases of pleural effusions (3). However, Ahmadinejad et al. reported a 59-year-old patient who complained of fever, dry cough, and dyspnea with massive pleural effusions, which was reported positive for COVID-19 (5). 
A limited body of knowledge is available about the lung manifestations of COVID-19 in children. Recent studies have suggested that COVID-19 pneumonia is mainly mild in children and has a good prognosis in those with no underlying diseases (2, 11). Chest CT scan in infected children can present characteristic changes of sub-pleural GGOs and consolidations with the surrounding halo, which is a suitable index for following up and evaluating the changes of lung lesions (2).
Pleural effusions can be caused by bacteria, viruses, tuberculosis, atypical mycobacterium, and fungus (10), but viral pathogens are rare causes of pleural effusion in children (12). Recently, Chen et al. reported a 12-year-old boy with COVID-19 and pleural effusions complicated by secondary Mycoplasma pneumonia infection (13). Additionally, a systematic review showed that pleural effusions are rare, and only three cases of COVID-19 in children were reported with pleural effusions (14).
Based on the results of this study, gastrointestinal symptoms can be the primary manifestations of COVID-19 infection and may present before respiratory symptoms in children. Pleural effusions in chest CT scans can be one of the manifestations of pulmonary involvement in infectious with COVID-19 in pediatrics.

4. Conclusion
Because of the prevalence of COVID-19, nowadays, a chest CT scan may be necessary for children with gastrointestinal symptoms if they have a complicated clinical situation. The pleural effusion should be considered a chest CT scan diagnostic manifestation of COVID-19, and the PCR test for COVID-19 should be conducted in these patients.

Ethical Considerations
Compliance with ethical guidelines
The Ethics Committee of Kurdistan University of Medical Sciences approved this research (Code: IR.MUK.REC.1399.256).

Funding
This research did not receive any grant from funding agencies in the public, commercial, or non-profit sectors. 

Authors' contributions
All authors equally contributed to preparing this article.

Conflicts of interest
The authors declared no conflict of interest.



References

1. Zhu N, Zhang D, Wang W, Li X, Yang B, Song J, et al. A novel COVID-19 from patients with pneumonia in China, 2019. The New England Journal of Medicine. 2020; 382(8):727-33. [PMID] [PMCID]
2. Xia W, Shao J, Guo Y, Peng X, Li Z, Hu D. Clinical and CT features in pediatric patients with COVID-19 infection: Different points from adults. Pediatric Pulmonology. 2020; 55(5):1169-74. [DOI:10.1002/ppul.24718] [PMID] [PMCID]
3. Matthai J, Shanmugam N, Sobhan P; Indian Society of Pediatric Gastroenterology, Hepatology and Nutrition; Pediatric Gastroenterology Chapter of Indian Academy of Pediatrics. COVID-19 disease (COVID-19) and the gastrointestinal system in children. Indian Pediatrics. 2020; 57(6):533-5. [DOI:10.1007/s13312-020-1851-5] [PMID] [PMCID]
4. Musolino AM, Supino MC, Buonsenso D, Ferro V, Valentini P, Magistrelli A, et al. Lung Ultrasound in children with Covid-19: Preliminary findings. Ultrasound in Medicine & Biology. 2020; 46(8):2094-8. [DOI:10.1016/j.ultrasmedbio.2020.04.026] [PMID] [PMCID]
5. Ahmadinejad Z, Salahshour F, Dadras O, Rezaei H, SeyedAlinaghi S. Pleural effusion as a sign of Coronavirus disease 2019 (COVID-19) pneumonia: A case report. IInfectious Disorders Drug Targets. 2021; 21(3):468-72. [PMID]
6. Ai T, Yang Z, Hou H, Zhan C, Chen C, Lv W, et al. Correlation of chest CT and RT-PCR testing for Coronavirus disease 2019 (COVID-19) in China: A Report of 1014 cases. Radiology. 2020; 296(2):E32-40. [DOI:10.1148/radiol.2020200642] [PMID] [PMCID]
7. Bernheim A, Mei X, Huang M, Yang Y, Fayad ZA, Zhang N, et al. Chest CT findings in COVID-19 disease-19 (COVID-19): Relationship to duration of infection. Radiology. 2020; 295(3):200463. [DOI:10.1148/radiol.2020200463] [PMID] [PMCID]
8. Zhou S, Wang Y, Zhu T, Xia L. CT features of COVID-19 disease 2019 (covid-19) pneumonia in 62 patients in Wuhan, China. AJR. American Journal of Roentgenology. 2020; 214(6):1287-94. [PMID]
9. Song F, Shi N, Shan F, Zhang Z, Shen J, Lu H, et al. Emerging 2019 novel Coronavirus (2019-nCoV) pneumonia. Radiology. 2020; 295(1):210-7. [DOI:10.1148/radiol.2020200274] [PMID] [PMCID]
10. Light, Richard W. Ch. 257: Disorders of the pleura and mediastinum. In: Fauci AS, Braunwald E, Kasper DL, Hauser SL, Longo DL, Jameson JL, Loscalzo J (eds.). Harrison’s Principles of Internal Medicine (17th ed.). https://www.amazon.com/Harrisons-Principles-Internal-Medicine-Single/dp/0071466339
11. Rahimzadeh G, Ekrami Noghabi M, Kadkhodaei Elyaderani F, Navaeifar M R, Enayati A A, Manafi Anari A, et al. COVID-19 infection in Iranian children: A case series of 9 patients. Journal of Pediatrics Review. 2019; 8(2):139-44. [DOI:10.32598/jpr.8.2.139]
12. Tiva G, Zampoli M, Vanker A. Pleural effusion in children associated with adenovirus infection. African Journal of Thoracic and Critical Care Medicine. 2015; 21(3):78-9. [DOI:10.7196/10.2015.v21i3.78]
13. Chen HR, Zou H, Xue M, Chen ZB, Chen WX. A case of childhood COVID-19 infection with pleural effusion complicated by possible secondary mycoplasma pneumoniae infection. The Pediatric Infectious Disease Journal. 2020; 39(7):e135-7. [DOI:10.1097/INF.0000000000002721] [PMID] [PMCID]
14. Shelmerdine SC, Lovrenski J, Caro-Domínguez P, Toso S; Collaborators of the European Society of Paediatric Radiology Cardiothoracic Imaging Taskforce. Coronavirus disease 2019 (COVID-19) in children: A systematic review of imaging findings. Pediatric Radiology. 2020; 50(9):1217-30. [DOI:10.1007/s00247-020-04726-w] [PMID] [PMCID]