While Covid-19 pandemic spreads around the world, there has been described different evolution in individuals according to risk groups.  The onset of the disease, which is mainly associated with respiratory distress, has its classic imaging presentation as ground-glass opacities in computer tomography (CT), although there are plenty of other possible findings. In pediatrics, the infection has its own particularities, rarely presenting severe course. Since April 2020, even if uncommon and less prevalent than in adults, cases with worse outcome started being described, mainly associated with multisystem inflammatory syndrome. Oncologic patients have higher mortality rates, and in the hematologic malignancies, this risk factor is even more evident, where severe lymphopenia is frequent. Proportionally, there is still small data about pediatric leukemia patients during Covid-19 disease, as there is also lack of imaging descriptions.

Evaluation of pediatric patients under leukemia treatment that had Sars Cov 2 infection, correlating clinical and radiologic presentations.

Data was collected from patients in the institution. Leukemia patients with molecular confirmation of Covid-19 were considered. Patients that didn't have confirmation of infection on RT-PCR test were excluded from analysis.

During the period from March 2020 to May 2021, there were 11 subjects with leukemia that had Sars Cov 2 proved infection. They were from 3 to 17 years old at Covid-19 diagnosis. From those, 6 had B ALL, 1 T ALL and 4 AML. 1 AML patient had previous allogeneic stem cell transplant.  6 patients had lymphocytes count < 550/mL. 6 patients underwent CT (5 with lymphopenia), and all presented radiologic signs. The main presentation was ground-glass opacity (GGO), present on all the 6 CTs. GGO was bilateral in 4 patients. The other findings were nodule (1), consolidation (1), interlobular septal thickening (1). The patient that presented consolidation had it localized, unilateral and perihilar. Regarding clinical evolution, 5 patients were classified as critical and transferred to ICU; all had a CT with GGO. 3 of them needed respiratory support and 1 needed only supplementary oxygen. This one had an atypical presentation, firstly suspected of transfusion-related acute lung injury, supported by clinical history. 2 patients had septic shock, renal failure and myocarditis combined. There was 1 decease (mortality 9% in the group), in a patient with severe respiratory presentation, associated with pulmonary Graft-versus-host disease.

This study showed that the main imaging finding in the group was GGO, which was present in all patients that had a CT performed.  All the subjects that needed intensive care had imaging proof of pulmonary involvement, even if the complications were also due to multisystemic inflammation. CT has been described with a high sensitivity for symptomatic Covid-19, and when it is very typical, can be diagnostic also if a negative RT-PCR. Patients undergoing leukemia treatment are immunocompromised and have low anti-viral defense, which could lead to higher risk of worse onset. The exam was not done for all patients in this study, the choice for indicating CT was based on clinic presentation and laboratory, which could bring a bias on positivity for GGO.

GGO is the main finding in CT scan in Covid-19, which was also found in this pediatric leukemia group.