# Long-Term Complications of Multisystem Inflammatory Syndrome in Children and Adults Post-COVID-19: A Systematic Review

## TL;DR

This review examines long-term complications of multisystem inflammatory syndrome in children and adults after COVID-19, emphasizing cardiac and other organ system issues.

## Contribution

The study systematically compiles and analyzes clinical data on MIS-C and MIS-A to highlight their complications and management.

## Key findings

- Cardiac complications were the most common manifestation of MIS post-COVID-19.
- Elevated inflammatory markers like CRP, ferritin, D-dimer, and IL-6 were consistently observed.
- Hospitalization and intensive care were frequently required, with some patients experiencing persistent complications.

## Abstract

The SARS-CoV-2 pandemic has posed global medical challenges due to its ability to affect multiple organ systems. Among the post-COVID-19 complications, multisystem inflammatory syndrome has emerged as a severe condition affecting both children (MIS-C) and adults (MIS-A). This review aims to compile and analyze published data to investigate clinical characteristics, laboratory findings, and outcomes of MIS post-COVID-19. A comprehensive search of various databases was conducted to identify studies reporting MIS-related complications in pediatric and adult populations post-COVID-19 infection. Screening, data extraction, and cross-checking were performed by two independent reviewers. Only 64 studies met our inclusion criteria, and compiled results revealed that cardiac complications were the predominant manifestation followed by gastrointestinal, hematologic, neurological, and mucocutaneous involvement. Laboratory findings consistently demonstrated elevated inflammatory markers including CRP, ferritin, D-dimer, and IL-6. Most patients required hospitalization, and many needed intensive care; treatment typically involved IVIG, corticosteroids, and biologic therapies. While most patients recovered, a subset experienced persistent complications. These findings highlight the importance of early recognition, multidisciplinary management, and structured follow-up for MIS. Future research is warranted to clarify the underlying mechanisms, risk factors, and long-term outcomes associated with MIS in post-COVID-19 patients.