Discussion:
Lung US represents a promising method to detect lung abnormalities in
adults with COVID-19 pneumonia and its pattern correlates with
radiological findings.8-10 At present, only one recent
report describes lung US findings in children, reporting high
concordance between radiologic and lung US imaging.12In China, where the COVID-19 epidemic started, many children underwent
chest X-ray and CT scan of the lung as part of the local diagnostic
protocols.5-6,16 The main radiologic findings on CT
scan in children with COVID-19 (bronchial thickening, ground-glass
opacity, inflammatory lung lesions) were suggestive of pneumonia and
were found also in patients with mild symptoms or
asymptomatic.16-17 It could be argued that despite the
mildness of respiratory symptoms, several children underwent chest
CT.6,16 Biologic effects of ionizing radiations are
widely known and it is mandatory for pediatricians to choose wisely the
best radiologic options balancing clinical conditions and possible
adverse events correlated to the diagnostic test.18 As
the majority of children with COVID-19 present mild symptoms and
complications are rare, CT scan could be reserved to the few severe or
complicated pediatric cases. Further to the radiological issues, the
risk of transporting COVID-19 patients for CT scan followed by the
mandatory decontamination procedure and the risk of nosocomial spread
makes this form of imaging risky and time consuming. The diagnostic role
of US in several respiratory conditions in children is nowadays widely
documented.19 In this COVID-19 outbreak scenario, we
pinpoint the usefulness of lung US for the evaluation of infected
children. The avowed advantages of lung POCUS in terms of bedside
evaluation, absence of radiation, low cost, no need for sedation and the
possibility of repeating the examination during follow-up should be
exploited and implemented.19-20 Moreover, the
possibility of performing lung US by a single operator at the bedside,
minimize the need of transferring the patient, consistently reducing the
potential risk of further infection spreading within the healthcare
personnel.11 Our small series highlighted that lung US
clearly documented signs of interstitial pneumonia in a considerable
proportion of pediatric patients, which were paucisymptomatic or
asymptomatic. When performed, lung US pattern correlated with
radiological findings. On subsequent repeated lung US, we found similar
findings, but observational time might have been too scarce as patients
were mostly discharged a few days after admission. More data are needed
to explore whether time interval between symptoms onset and lung US
execution modifies ultrasonographic findings. The power of lung US in
orientating the management of patients is increased by its correlation
with clinical information. Despite the small sample described in our
series, we found that lung US can show signs of interstitial pneumonia
also in the absence of relevant clinical symptoms. This did not
significantly affect clinical management of the patients; therapeutic
choices were mostly determined by risky comorbidities. A possible
limitation to the spread of lung US is the lack of specific standardized
and certified training on lung US. 19-20
The current rapid worldwide spread of SARS-CoV-2 infection requires
continual improvement of knowledge about clinical manifestations of
COVID-19. As clinical characteristics of pediatric COVID-19 differ from
adults, it is of interest to determine whether pediatric lung US shares
the same imaging pattern of adults, and whether COVID-19 pneumonia may
differ from other virus pneumonias. It could be argued that lung US may
be of particular need in guiding therapeutic choices especially for
moderate to severe cases. Our study represents a preliminary report of
lung US characteristics and usefulness in children affected by COVID-19.
Implementation of LUS during the COVID-19 outbreak is of great interest.