Case Report: Multisystem inflammatory syndrome in children with associated proximal tubular injury

Abstract

Introduction: SARS-CoV-2 infection in the pediatric population can be associated with a multiorgan inflammatory syndrome called children's multisystem inflammatory syndrome (MIS-C). The kidneys can be affected by a broad spectrum of possible injuries, whose pathogenetic mechanisms are still unclear.Case report: We report the case of a 5-year-old boy with severe cardiac involvement in the context of MIS-C. After two weeks of hospitalization, an abdominal ultrasound showed massive bladder "debris", followed by the onset of normoglycemic glycosuria. Over time, there was a progressive increase in glycosuria, and the presence of a mat of amorphous phosphate crystals was evidenced on urinary sediment. Together with the findings of hypo-uricemia, increased urinary uric acid, and globally increased urinary amino acids, a clinical picture of kidney proximal tubular damage with secondary Fanconi-like syndrome took shape.

Discussion: This case report describes the case of a patient with MIS-C with cardiac and kidney involvement characterized by proximal tubular damage, which slowly improved but still persisted at the 8-month follow-up. The pathogenesis of the damage is unclear and probably multifactorial.

Keywords: Fanconi syndrome; MIS-C multisystem inflammatory syndrome in children; SARS – CoV – 2; bladder debris; kidney injury; proximal tubule injury.

Figure 1

Timeline of clinical events, diagnostic examinations, and treatments of the patient.

Figure 2

Ultrasound examination showing massive bladder debris in a 5-year-old child affected by MIS-C (A, B). First incidental finding of massive sediment and floating bladder debris at abdominal ultrasound examination. (C, D). Reduction of the debris after X days at ultrasound control examination.