A Rare Case of a Child Diagnosed With Multisystem Inflammatory Syndrome After COVID-19 Presenting With Renal Infarctions and Transient Blast Cells: A Case Report and Literature Review.

Multisystem inflammatory syndrome in children (MIS-C) can develop weeks after the Coronavirus disease 2019 (COVID-19). The disease's clinical spectrum includes persistent febrile illness, features resembling Kawasaki disease, and cytokine storm symptoms. In severe cases, multisystem organ failure and death may result if not treated promptly. This report discusses a rare case of a 13-year-old girl presenting with fever and acute kidney injury (AKI) eight weeks after recovering from COVID-19 who was diagnosed with MIS-C. A 13-year-old female presented with a fever and abdominal pain following a recent COVID-19. A physical examination revealed a febrile, ill-looking child with abdominal tenderness. Pancytopenia, transaminitis, AKI, and a hyperinflammatory state were noted in the initial laboratory workup. Furthermore, blast cells were seen on the peripheral blood smear. Despite appropriate empiric antibiotic therapy for sepsis, she did not show signs of clinical improvement. An abdominal computed tomography (CT) scan revealed multiple focal areas of hypoattenuating lesions involving both kidneys, suggestive of bilateral renal infarction. Since she met the criteria of the Centers for Disease Control and Prevention (CDC) for MIS-C diagnosis, a high dose of intravenous immunoglobulin (IVIG) led to a dramatic improvement in the patient's condition and complete recovery from her illness. This case report describes a rare clinical presentation of MIS-C in a child who presented with AKI due to presumably thrombotic events and transient blast cells in blood film secondary to a severe inflammatory process. Further studies are needed to determine the prevalence of thrombotic AKI associated with MIS-C.