Multisystem Inflammatory Syndrome in Children (MIS-C): A Review of Short- and Long-Term Complications

Sayedeh Zalfa  Modarresi; Shekoofeh  Savabieh; Naeimeh  Naserzadeh; Maryam  Yazdanparast; Somayeh  Talaeipour

doi:10.18502/ijpho.v16i1.20428

Sayedeh Zalfa Modarresi Hematology and Oncology Research Center, Non-communicable Diseases Research Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Shekoofeh Savabieh Children Growth Disorder Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Naeimeh Naserzadeh Children Growth Disorder Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Maryam Yazdanparast Hematology and Oncology Research Center, Non-communicable Diseases Research Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Somayeh Talaeipour Children Growth Disorder Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

DOI: https://doi.org/10.18502/ijpho.v16i1.20428

Keywords: Cardiovascular Diseases, Hematologic Diseases, Multisystem Inflammatory Syndrome in Children, Post-Acute COVID-19 Syndrome, Sequelae

Abstract

Multisystem Inflammatory Syndrome in Children (MIS-C) is a rare but serious post-infection disorder associated with SARS-CoV-2 infection, typically occurring 2-6 weeks after acute COVID-19. The syndrome is characterized by persistent fever, multisystem organ impairment, and laboratory evidence of inflammation. The affected individuals require prompt diagnosis and treatment to avoid morbidity. The short-term complications are widespread during the acute phase of the disease, often requiring intensive care. Cardiovascular symptoms occur in up to 80% of the cases. Gastrointestinal presentations are common along with respiratory, neurologic, renal and mucocutaneous complications.

Hematologic complications are one of the most frequent organ system presentations of MIS-C. They occur in over 50% of patients and pose significant thrombotic risks. Thrombocytopenia is observed in approximately 40-60% of patients, frequently with coagulopathy and elevated D-dimer, indicating a hypercoagulable state. There is a heightened prevalence of thromboembolic events in the form of deep vein thrombosis or pulmonary embolism due to endothelial injury and cytokine storms. These features point to the prothrombotic profile of MIS-C, which is distinct from other pediatric inflammatory syndromes. Also, late sequelae, an inadequately researched subject, include chronic cardiac defects, such as dilatation of coronary arteries or reduced ventricular function in 10-20% of survivors, who require ongoing echocardiography. Respiratory, gastrointestinal, and neurocognitive dysfunctions have been reported in follow-up observations, although most children return to normal after a few months. Hematological recovery is typically excellent, but chronic thrombotic risks exist in only some serious cases of the disease. While the short-term prognosis of MIS-C is generally favorable, uncertainties persist regarding its long-term complications. Standardized follow-up protocols for the complications of MIS-C are warranted to detect subclinical abnormalities and guide ongoing management. Continued surveillance and longitudinal research are essential to fully elucidate the natural history of the disease and optimize the outcomes for the survivors.