A recent report describes a case of a previously healthy 10-year-old boy who presented with a seven-day history of fever, abdominal pain, and diarrhea. His parents reported no history of contact with a COVID-19 patient or symptomatic acquaintances. 

Physical examination revealed him to be afebrile, dehydrated, prostrated, and with conjunctival erythema. The next day the patient developed a high fever, which persisted at a lower level until the seventh day. Laboratory tests showed anemia, 14,600 leukocytes/mm³ (90% polymorphonuclear) but with only 5% lymphocytes/mm³. He also showed Hypoxemia. His chest tomography showed ground-glass opacities in less than 25% of the lungs, small bilateral pleural effusion, and abdominal tomography showed enlargement of the lymph nodes, measuring up to 2.6 cm. His electrocardiogram was normal. 

On the fourth day of hospitalization, he had high levels of inflammatory markers associated with high ferritin, fibrinogen, and hypoalbuminemia, with normal lactic acid, creatinine, AST, ALT, CPK, and CK-MB. His chest radiography showed increased cardiac area. After five days, his chest tomography revealed consolidation in the left lower lobe lung with an air bronchogram associated with some lobe volume loss, suggesting atelectasis. He also showed Minimal bilateral basal pleural thickening, with significant pleural effusion, pericardial effusion, and ascites. Nasopharyngeal swabs at admission and on the 8th day of hospitalization were negative for SARS CoV-2 or Influenza (A and B) RNA. On the 6th day of hospitalization, his d-dimer levels were higher (5000 ng/mL) with a CRP of 140 mg/L. Autoantibodies tests and serology for HIV and Hepatitis B/C were negative.

Since admission, the patient received ceftriaxone for ten days simultaneously with oseltamivir for five days and macrolide from the 3rd day of hospitalization (4 days of clarithromycin followed by four days of azithromycin). On the 4th day of hospitalization, he received red cell concentrate due to reduced hemoglobin and hematocrit. He also received Albumin and furosemide on the 4, 5, 8, and 10th days of hospitalization; and three doses of hydroxychloroquine. On the ninth day of hospitalization, his echocardiogram was normal, the level of albuminemia was 3.4 g/dL, and CRP was 37 mg/L.

Despite only supportive measures, the child recovered with a resolution of ascites, pleural and pericardium effusion, and normalization of laboratory tests. He was discharged on the 14th day of hospitalization and was asymptomatic at the last observation two months later. 

Matsuda EM, Santos SAD, Castejon MJ, Ahagon CM, Campos IB, Brígido LFM. COVID-19 in children: a case report of Multisystem Inflammatory Syndrome (MIS-C) in São Paulo, Brazil. Braz J Infect Dis. 2020 Nov-Dec;24(6):580-582. doi: 10.1016/j.bjid.2020.09.002. Epub 2020 Oct 6. PMID: 33035469; PMCID: PMC7536544.