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

Area of Science:

• Pediatric Nephrology
• Infectious Diseases
• Critical Care Medicine

Background:

• Children's multisystem inflammatory syndrome (MIS-C) is a serious complication of SARS-CoV-2 infection in children.
• Kidney involvement in MIS-C can manifest as a wide range of injuries with unclear pathogenesis.
• Early identification and understanding of renal complications are crucial for managing MIS-C.

Observation:

• A 5-year-old boy with severe cardiac involvement due to MIS-C presented with significant bladder "debris" on ultrasound.
• Following this, the patient developed normoglycemic glycosuria, progressive hyperuricosuria, and generalized aminoaciduria.
• Urinary sediment analysis revealed amorphous phosphate crystals, indicative of tubular dysfunction.

Findings:

• The clinical presentation suggested proximal tubular damage, leading to a secondary Fanconi-like syndrome.
• This kidney injury, associated with MIS-C and cardiac complications, showed slow improvement but persisted at 8-month follow-up.
• The exact pathogenetic mechanisms remain multifactorial and require further investigation.

Implications:

• This case highlights the potential for severe renal tubular dysfunction in pediatric MIS-C patients.
• It underscores the importance of comprehensive renal monitoring in children with MIS-C, particularly those with cardiac involvement.
• Further research into the mechanisms of kidney injury in MIS-C may lead to targeted therapies and improved patient outcomes.