[Multisystemic inflammatory syndrome in children after severe acute respiratory syndrome coronavirus 2 infection: a clinical analysis of four cases]

OBJECTIVES

To investigate the clinical features and treatment strategies of multisystemic inflammatory syndrome in children (MIS-C) after severe acute respiratory syndrome coronavirus 2 infection.

METHODS

A retrospective analysis was performed on the medical data of four children with MIS-C who were admitted to the Department of Cardiology, Xuzhou Children's Hospital, Xuzhou Medical Universityfrom January to February 2023.

RESULTS

All four children had multiple organ involvements and elevated inflammatory markers, with a poor response to standard therapy for Kawasaki disease after admission. Two children were treated with intravenous immunoglobulin therapy pulse therapy twice, and all four children were treated with glucocorticoids. The children had a good prognosis after the treatment.

CONCLUSIONS

MIS-C often appears within 4-6 weeks or a longer time after severe acute respiratory syndrome coronavirus 2 infection, and anti-inflammatory therapy in addition to the standard treatment regimen for Kawasaki disease can help to achieve a favorable treatment outcome.

A Young Adult With Multisystem Inflammatory Syndrome in Adults With Concomitant Mycoplasma Infection: A Case Report

Several cases of Multisystem Inflammatory Syndrome in Adults (MIS-A) have been reported in adults since June 2020 after COVID-19 was first reported in December 2019. It was initially reported in children as MIS-C with Kawasaki-like disease, but a similar condition has been well recognized in adults. Although Mycoplasma co-infection has been reported with COVID-19, to our knowledge, concomitant Mycoplasma pneumoniae infection has not been reported together with MIS-A. We present a case of MIS-A with concomitant M. pneumoniae infection. It is unclear if concomitant Mycoplasma infection resulted in increased severity of the patient's illness or if it resulted in inciting the immune response in our patient who had recently recovered from COVID-19 infection. This case highlights the need to diagnose a patient with a typical presentation of MIS-A and any concomitant infection or illnesses.

A Review of Coronaviruses Associated With Kawasaki Disease: Possible Implications for Pathogenesis of the Multisystem Inflammatory Syndrome Associated With COVID-19

Multisystem Inflammatory Syndrome in Children (MIS-C), representing a new entity in the spectrum of manifestations of COVID-19, bears symptomatic resemblance with Kawasaki Disease (KD). This review explores the possible associations between KD and the human coronaviruses and discusses the pathophysiological similarities between KD and MIS-C and proposes implications for the pathogenesis of MIS-C in COVID-19. Since 2005, when a case-control study demonstrated the association of a strain of human coronavirus with KD, several studies have provided evidence regarding the association of different strains of the human coronaviruses with KD. Thus, the emergence of the KD-like disease MIS-C in COVID-19 may not be an unprecedented phenomenon. KD and MIS-C share a range of similarities in pathophysiology and possibly even genetics. Both share features of a cytokine storm, leading to a systemic inflammatory response and oxidative stress that may cause vasculitis and precipitate multi-organ failure. Moreover, antibody-dependent enhancement, a phenomenon demonstrated in previous coronaviruses, and the possible superantigenic behavior of SARS-CoV-2, possibly may also contribute toward the pathogenesis of MIS-C. Lastly, there is some evidence of complement-mediated microvascular injury in COVID-19, as well as of endotheliitis. Genetics may also represent a possible link between MIS-C and KD, with variations in FcγRII and IL-6 genes potentially increasing susceptibility to both conditions. Early detection and treatment are essential for the management of MIS-C in COVID-19. By highlighting the potential pathophysiological mechanisms that contribute to MIS-C, our review holds important implications for diagnostics, management, and further research of this rare manifestation of COVID-19.

How Children Are Protected From COVID-19? A Historical, Clinical, and Pathophysiological Approach to Address COVID-19 Susceptibility

The origin and the global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) in early 2020 was accompanied by high rates of mortality in regions belonging to the ancient silk road, such as the south of China, Iran, Turkey and the northern parts of Italy. However, children seem to be spared in the epidemic as very small percentage worldwide being ill. The protection of children and neonates suggests the involvement of a specific component of adaptive immunity present at early development. Native immunoglobulin belonging to the class of IgM is abundantly present in neonates and children and is known for its recognition of self- and altered self-antigens. Native IgM may be able to neutralize virus by the recognition of endogenous "danger signal" encoded in the viral envelope and originally imprinted in the membranes of infected and stressed cells. Noteworthy, thrombosis and vasculitis, two symptoms in severely affected adult and pediatric patients are shared between COVID-19 and patients with Behcet's disease, an autoimmune disorder exhibiting a region-specific prevalence in countries of the former silk road. Molecular mechanisms and clinical indicators suggest reactive oxygen species as trigger factor for severe progression of COVID-19 and establish a link to the innate immune defense against bacteria. The selective pressure exerted by bacterial pathogens may have shaped the genetics of inhabitants at this ancient trade route in favor of bacterial defense, to the detriment of severe COVID-19 progression in the 21th century.

Kawasaki like illness due to COVID-19: a review of the literature

INTRODUCTION

Viral infections have been described as triggers for Kawasaki Disease (KD), a medium vessel vasculitis that affects young children. Akin to the H1N1 pandemic in 2009, there is a similar rise in the incidence of KD in children affected with Coronavirus disease 2019 (COVID-19). Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-COV-2) has been reported to induce an exaggerated systemic inflammatory response resulting in multi-organ involvement, particularly initiated with pulmonary parenchymal damage. This review article will discuss KD-like manifestations in COVID-19 patients in the pediatric cohort.

METHODOLOGY

Search terms "Kawasaki" "COVID-19" "SARS-COV-2" "PIM-TS" and "MIS-C" were used to look for relevant articles in PubMed and Google Scholar published in the last 5 years.

RESULTS

There is some evidence to suggest that SARS-CoV-2 stimulates dysfunctional and hyperactive immune reactions mimicking KD in young patients.

CONCLUSIONS

Therapeutic options, both investigational and repurposed, include intravenous immunoglobulins, steroids and anticoagulation. More studies are required to evaluate the effectiveness of these treatment options.

Association between SARS-CoV-2 infection and Kawasaki-like multisystem inflammatory syndrome: a retrospective matched case-control study, Paris, France, April to May 2020

We assessed the association between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and Kawasaki disease (KD)-like multisystem inflammatory syndrome in a retrospective case–control study in France. RT-PCR and serological tests revealed SARS-CoV-2 infection in 17/23 cases vs 11/102 controls (matched odds ratio: 26.4; 95% confidence interval: 6.0–116.9), indicating strong association between SARS-CoV-2 infection and KD-like illness. Clinicians should keep a high level of suspicion for KD-like illness during the COVID-19 pandemic.

The wide spectrum of Kawasaki-like disease associated with SARS-CoV-2 infection

Introduction: On June 2020, the first case of concurrent Covid-19 and Kawasaki disease (KD) was published. After this first description, further works reported new cases of children affected by KD and KD-like syndrome after SARS-CoV-2 infection. The clinical and biochemical features of these patients differed from the historical cohorts of KD, suggesting the possibility of a new multi-systemic inflammatory syndrome. Is still unclear if this new clinical entity, often referred as pediatric inflammatory multisystem syndrome (PIMS) or multi-system inflammatory syndrome in children (MIS-C), could be considered as part of the KD spectrum or is a new disease with different pathogenic mechanisms and uniquely linked to SARS-CoV-2 infection. The authors searched the available literature in MedLine (via Pubmed) with the terms ('coronaviruses' OR 'coronavirus') AND ('Kawasaki disease') for English studies without any temporal limit. Areas covered: This review aims to comprehensively describe multisystem inflammatory syndromes affecting children during Coronaviruses outbreak, and to evaluate the possible pathogenic role of human Coronaviridae in KD and KD-like syndromes. Expert opinion: An increased incidence of PIMS-TS, during the Covid-19 pandemic has been reported, suggesting that SARS-CoV-2 may trigger a severe hyper-inflammatory syndrome in childhood. The pathophysiological mechanisms of this disease are still unclear. Based on these findings, SARS-CoV-2 may be considered another trigger in the complex mosaic about the relationship among infectious agents and the occurrence of systemic hyper-inflammation related syndromes.

Severe COVID-19, multisystem inflammatory syndrome in children, and Kawasaki disease: immunological mechanisms, clinical manifestations and management

Multisystem inflammatory syndrome (MIS-C) is a pediatric hyperinflammation disorder caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). It has now been reported from several countries the world over. Some of the clinical manifestations of MIS-C mimic Kawasaki disease (KD) shock syndrome. MIS-C develops 4–6 weeks following SARS-CoV-2 infection, and is presumably initiated by adaptive immune response. Though it has multisystem involvement, it is the cardiovascular manifestations that are most prominent. High titres of anti-SARS-CoV-2 antibodies are seen in these patients. As this is a new disease entity, its immunopathogenesis is not fully elucidated. Whether it has some overlap with KD is still unclear. Current treatment guidelines recommend use of intravenous immunoglobulin and high-dose corticosteroids as first-line treatment. Mortality rates of MIS-C are lower compared to adult forms of severe COVID-19 disease.

COVID-19 as an Immune Complex Hypersensitivity in Antigen Excess Conditions: Theoretical Pathogenetic Process and Suggestions for Potential Therapeutic Interventions

Because of particular properties of SARS-Cov-2, such as an high infection speed, its antigenic nature, evolutionarily unknown to the human immune system, and/or a viral interference on the immune response mechanisms, this virus would determine in the subjects a delayed anomalous (slow and/or low) immune response, ineffective and, finally, self-damaging. The hypothetical pathogenetic process for covid-19 could occur in three phases: a) Viral phase, asymptomatic or weakly symptomatic, with an a-specific innate immune response; b) Immunological phase, intermediately symptomatic, with an anomalous specific immune response (delayed, slow and/or low synthesis of IgM and IgG) in antigen excess conditions, immune complex formation and complement activation with tissue damages; c) Hemo-vascular phase, severely symptomatic, where complement-mediated tissue damages would induce vascular inflammation and systemic alteration of the coagulation homeostasis. This hypothesis is well supported by the immune-histochemical and microscopic demonstration in severe patient lungs of co-localized spike viral proteins, terminal components of the activated complement system (C5b-9 membrane attack complex) and microvascular deposits of small fibrin thrombi. This picture could be aggravated by the involvement of neutrophils and macrophages, releasing additional lytic and inflammatory factors. Thus, covid-19 would arise as a simple viral infection, develop as a diffuse immune complex hypersensitivity and explode as a systemic hemo-vascular pathology. If this hypothesized process would be real, suitable therapeutic interventions might be carried out, able to interfere with or block the critical factors in the various phases.

Kawasaki-like disease in children with COVID-19: A hypothesis

With rapid spread of severe acute respiratory syndrome- corona virus-2 (SARS-COV-2) globally, some new aspects of the disease have been reported. Recently, it has been reported the incidence of Kawasaki-like disease among children with COVID-19. Since, children had been known to be less severely affected by the virus in part due to the higher concentration of Angiotensin converting enzyme (ACE)-2 receptor, this presentation has emerged concerns regarding the infection of children with SARS-COV2. ACE2 has anti-inflammatory, anti-fibrotic and anti-proliferative characteristics through converting angiotensin (Ag)-II to Ang (1-7). ACE2 receptor is downregulated by the SARS-COV through the spike protein of SARS-CoV (SARS-S) via a process that is tightly coupled with Tumor necrosis factor (TNF)-α production. TNF-α plays a key role in aneurysmal formation of coronary arteries in Kawasaki disease (KD). Affected children by COVID-19 with genetically-susceptible to KD might have genetically under-expression of ACE2 receptor that might further decrease the expression of ACE2 due to the downregulation of the receptor by the virus in these patients. It appears that TNF- α might be the cause and the consequence of the ACE2 receptor downregulation which results in arterial walls aneurysm. Conclusion: Genetically under-expression of ACE2 receptor in children with genetically-susceptible to KD who are infected with SARS-CoV-2 possibly further downregulates the ACE2 expression by TNF-α and leads to surge of inflammation including TNF-α and progression to Kawasaki-like disease.

Kawasaki Disease and COVID-19

The recent passing away of Dr. Tomisaku Kawasaki, who first described what is now known as Kawasaki Disease (KD), and recent reports of a multisystem inflammatory disease in children associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (MIS-C), makes a review on KD and MIS-C timely. Kawasaki Disease is a systemic vasculitis with predilection for coronary arteries occurring mostly in early childhood. The main features are high fever, extensive skin rash, cheilitis with red, cracking, bleeding lips and strawberry tongue, conjunctivitis, erythema and induration of hands and feet, subsiding with periungual peeling, cervical lymphadenopathy, and coronary artery dilation/aneurysms. Treatment consists of intravenous (IV) immunoglobulin (Ig) plus acetylsalicylic acid. MIS-C is considered a cytokine storm with high fever, inflammation, multi-organ dysfunction, that shares features with KD, toxic shock, and macrophage activation syndrome. Many children require admission to paediatric intensive care units for circulatory support. Bacterial sepsis, staphylococcal toxic shock syndrome, and enterovirus-causing myocarditis should be excluded. Treatment is not standardized and includes IVIg, IV methylprednisolone and IL-6 and IL-1 inhibitors.

Kawasaki Disease: an Update

PURPOSE OF REVIEW

Provide the most recent updates on the epidemiology, pathogenesis, and treatment advances in Kawasaki disease.

RECENT FINDINGS

Treatment advances in complex, IVIG-refractory cases of Kawasaki disease. Multisystem inflammatory syndrome, a newly reported inflammatory condition with Kawasaki-like features and an association with the 2019 Coronavirus (COVID-19). Kawasaki disease (KD) is a rare systemic inflammatory disease that predominately affects children less than 5 years of age. Pathogenesis of KD remains unknown; the leading theory is that an unknown stimulus triggers an immune-mediated inflammatory cascade in a genetically susceptible child. Classic KD is a clinical diagnosis based on set criteria and excluding other similar clinical entities. Patients who do not fulfill complete diagnostic criteria for KD are often referred to as atypical (or incomplete) KD. The most feared complication of KD is coronary artery abnormality development, and patients with atypical KD are also at risk. Administration of intravenous immunoglobulin (IVIG) and aspirin has greatly reduced the incidence of coronary lesions in affected children. Several other immune-modulating therapies have recently been utilized in complex or refractory cases.

Pediatric Inflammatory Multisystem Syndrome: Statement by the Pediatric Section of the European Society for Emergency Medicine and European Academy of Pediatrics

A rise in cases with a new hyperinflammatory disease in children has been reported in Europe and in the Unites States of America, named the Pediatric Inflammatory Multisystem Syndrome-temporally associated with SARS-CoV-2 (PIMS-TS). There appears to be a wide spectrum of signs and symptoms with varying degrees of severity, including a toxic shock like presentation with hypovolaemia and shock, and a Kawasaki-like presentation with involvement of the coronary arteries. Most of these children have evidence of a previous infection with SARS-CoV-2, or a history of significant exposure, but not all. Limited data exist on the incidence of PIMS-TS, but it remains a rare condition. Early recognition and escalation of care is important to prevent the development of serious sequelae, such as coronary artery aneurysms. Clinicians assessing febrile children in primary and secondary care should include PIMS-TS in their differential diagnoses. In children fulfilling the case definition, additional investigations should be undertaken to look for evidence of inflammation and multiorgan involvement. Suspected cases should be discussed with experts in pediatric infectious diseases at an early stage, and advice should be sought from critical care in more severe cases early. There is limited consensus on treatment; but most children have been treated with immunoglobulins or steroids, and with early consideration of biologicals such anti-TNF and anti-IL1 agents. Treatment should ideally be within the context of controlled treatment trials. Clinicians are encouraged to document and share their cases using research registries.