1 | INTRODUCTION
Since the end of December 2019, coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread worldwide, becoming the first pandemic of the 21st century1. Since the beginning of the COVID-19 pandemic, children have been less frequently and severely involved than adults, requiring hospitalization only in 5%–10% of cases2. This likely explains the paucity of children-related articles in scientific literature, even with a vertiginous increase in COVID-19 articles. However, recent studies have identified an emerging novel spectrum of the disease in children, including a multisystem inflammatory condition with overlapping features of toxic shock syndrome 3. To date, the absolute number of those cases with prominent cardiovascular compromise is still low and respiratory symptoms remain the main reason for Pediatric Intensive Care Unit admissions for COVID-19 4. The PCR-rapid test is not feasible in all hospitals and a slow turnaround time is an extra burden5. Therefore, a rapid, economical and reproducible test to accurately identify the disease in its early stages is critical.
The mild pattern of disease in children’s findings is usually subtle compared to adults, and therefore may not be detected on chest X-ray (CXR)6. Chest Computed tomography (CT) is undoubtedly the best imaging modality to accurately assess lung involvement in most respiratory illnesses, including COVID-19; however, the cost and possible harmful effects of radiation on a growing child’s body must not be ignored, as even low-dose ionizing radiations may increase cancer risk in exposed children 7. In addition, pathologic findings are often found later in the disease course, and CT is a poor imaging choice for follow-up or serial imaging 8.
Several studies have shown that lung ultrasound (LUS) is a useful and accurate tool for detecting pneumonia in children9,10. Other studies have even shown that LUS can predict more severe pneumonia and monitor antibiotic response. Recently, different LUS patterns have been used to differentiate viral from bacterial pneumonia by defining their etiology in child 11. Although several studies have investigated LUS in adult COVID-19 patients, the literature for the pediatric age group is limited12. This study aimed to review the available evidence of the use of LUS versus CXR and chest CT in children suspected to have COVID-19 pneumonia and sought to identify an alternative diagnostic technique that is less invasive than radiation and more practical in early-stage diagnosis and follow-up monitoring of COVID-19 pneumonia.