Is multisystem inflammatory syndrome in children on the Kawasaki syndrome spectrum?

The HyperPed-COVID international registry: Impact of age of onset, disease presentation and geographical distribution on the final outcome of MIS-C

OBJECTIVES

The aim of the study was to establish an international multicenter registry to collect data on patients with Multisystem Inflammatory Syndrome in Children (MIS-C), in order to highlight a relationship between clinical presentation, age of onset and geographical distribution on the clinical outcome.

STUDY DESIGN

Multicenter retrospective study involving different international societies for rare immunological disorders.1009 patients diagnosed with MIS-C between March and September 2022, from 48 centers and 22 countries were collected. Five age groups (<1, 1-4, 5-11, 12-16, >16 years) and four geographic macro-areas, Western Europe, Central-Eastern Europe, Latin America, Asian-African resource-limited countries (LRC), were identified.

RESULTS

Time to referral was significantly higher in LRC. Intensive anti-inflammatory treatment, including biologics, respiratory support and mechanic ventilation were more frequently used in older children and in European countries. The mortality rate was higher in very young children (<1 year), in older patients (>16 years of age) and in LRC. Multivariate analysis identified the residence in LRC, presence of severe cardiac involvement, renal hypertension, lymphopenia and non-use of heparin prophylaxis, as the factors most strongly associated with unfavorable outcomes.

CONCLUSIONS

The stratification of patients by age and geographic macro-area provided insights into the clinical presentation, treatment and outcome of MIS-C. The mortality and sequelae rates exhibited a correlation with the age and geographical areas. Patients admitted and treated in LRC displayed more severe outcomes, possibly due to delays in hospital admission and limited access to biologic drugs and to intensive care facilities.

A comparison of pediatric inflammatory multisystem syndrome temporarily-associated with SARS-CoV-2 and Kawasaki disease

The connection between Pediatric Inflammatory Multisystem Syndrome (PIMS) and Kawasaki Disease (KD) is not yet fully understood. Using the same national registry, clinical features and outcome of children hospitalized in Germany, and Innsbruck (Austria) were compared. Reported to the registry were 395 PIMS and 69 KD hospitalized patients. Patient age in PIMS cases was higher than in KD cases (median 7 [IQR 4-11] vs. 3 [IQR 1-4] years). A majority of both PIMS and KD patients were male and without comorbidities. PIMS patients more frequently presented with organ dysfunction, with the gastrointestinal (80%), cardiovascular (74%), and respiratory (52%) systems being most commonly affected. By contrast, KD patients more often displayed dermatological (99% vs. 68%) and mucosal changes (94% vs. 64%), plus cervical lymph node swelling (51% vs. 34%). Intensive care admission (48% vs. 19%), pulmonary support (32% vs. 10%), and use of inotropes/vasodilators (28% vs. 3%) were higher among PIMS cases. No patients died. Upon patient discharge, potentially irreversible sequelae-mainly cardiovascular-were reported (7% PIMS vs. 12% KD). Despite differences in age distribution and disease severity, PIMS and KD cases shared many common clinical and prognostic characteristics. This supports the hypothesis that the two entities represent a syndrome continuum.

Multicentre observational study on multisystem inflammatory syndrome related to COVID-19 in Argentina

BACKGROUND

The impact of the pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) in low- and middle-income countries remains poorly understood. Our aim was to understand the characteristics and outcomes of PIMS-TS in Argentina.

METHODS

This observational, prospective, and retrospective multicenter study enrolled patients younger than 18 years-old manifesting PIMS-TS, Kawasaki disease (KD) or Kawasaki shock syndrome (KSS) between March 2020 and May 2021. Patients were followed-up until hospital discharge or death (one case). The primary outcome was pediatric intensive care unit (PICU) admission. Multiple logistic regression was used to identify variables predicting PICU admission.

RESULTS

Eighty-one percent, 82%, and 14% of the 176 enrolled patients fulfilled the suspect case criteria for PIMS-TS, KD, and KSS, respectively. Temporal association with SARS-CoV-2 was confirmed in 85% of the patients and 38% were admitted to the PICU. The more common clinical manifestations were fever, abdominal pain, rash, and conjunctival injection. Lymphopenia was more common among PICU-admitted patients (87% vs. 51%, p < 0.0001), who also showed a lower platelet count and higher plasmatic levels of inflammatory and cardiac markers. Mitral valve insufficiency, left ventricular wall motion alterations, pericardial effusion, and coronary artery alterations were observed in 30%, 30%, 19.8%, and 18.6% of the patients, respectively. Days to initiation of treatment, rash, lymphopenia, and low platelet count were significant independent contributions to PICU admission.

CONCLUSION

Rates of severe outcomes of PIMS-TS in the present study agreed with those observed in high-income countries. Together with other published studies, this work helps clinicians to better understand this novel clinical entity.

Methylprednisolone pulses as an initial treatment in hyperinflammatory syndrome after COVID-19 in children: evaluation of laboratory data, serial echocardiography and outcome: a case series

BACKGROUND

Hyper-inflammatory syndrome in children and young adult occur 2-6 weeks after COVID-19 infection or closed contact with COVID-19 persons. In this study, the laboratory data and echocardiography and abdominal ultrasonography assessments were evaluated before and after Methylprednisolone pulse as an initial treatment of hyper-inflammatory syndrome. Therefore, the aim of this study is to assessment the clinical manifestations and laboratory data and outcome after methylprednisolone pulse as an initial treatment.

METHOD

In this retrospective study, the demographic status, clinical features, laboratory data, echocardiography, abdominal ultrasound, treatment and outcome of 31 pediatric patients under 16 years old, with inflammatory process after COVID-19 were evaluated. The clinical assessments, laboratory data, sonography and echocardiography were evaluated before and after methylprednisolone pulse. The patients were divided in two age group < and ≥ 7 years old and the clinical manifestations were compared with each other. The Mann-Whitney U test was used to assess the difference in quantitative variables between two groups. To compare pre- and post- treatment values, Wilcoxol test was used. To assess the correlation between qualitative variables chi-square test was used. The level of significant was considered 0.05. These patients with fever and hyper-inflammation features admitted to the referral pediatric rheumatology ward in Children Medical Center of Tehran University of medical sciences, from April 2020 to May 2021 were assessed.

RESULT

The mean age ± SD were (5.94 ± 3) and 51.6% (16) patients were male and 48.4% (15) patients were female. The most documented of previous COVID infection were antibody positive in about 27 (87%) patients. Moreover, 1 (3.8%) was PCR positive, 2 (7.7%) were positive in both PCR and serology and 3(11.5%) had closed contact with COVID-19 patients. About 9(29%) of patients were admitted in Intensive Care Unit (ICU). There were significant correlation between days of delay in starting treatment and ICU admission (P-value = 0.02). The mortality rate was negative in patients and no re-hospitalization was documented. There were significant differences (P-value < 0.05) between lymphocytes, platelet, Erythrocyte Sedimentation rate, C-reactive protein, Aspartate transaminase, Alanine transaminase and ferritin before and after treatment. Skin rashes and cardiac involvement totally as carditis (myocarditis, vulvulitis and pericarditis) (33.3%) and coronary involvements (53.3%) were the most prominent initial presentation in patients. There were near significant correlation (P-value = 0.066) between ferritin level and carditis before treatment. Cervical lymphadenopathy was seen significantly more in ≥ 7 years old (P-value = 0.01).

CONCLUSION

Multisystem inflammatory system in children as a hyperinflammatory syndrome could be treated with first step methylprednisolone pulse with decreasing inflammation in laboratory data and cardiac involvements and good outcome. Furthermore, the ferritin level may be one of the predictor of severe hyper-inflammatory syndrome leading to aggressive and urgent treatment with methylprednisolone pulse.

Refractory Cardiogenic Shock Secondary to Acute Myocarditis in a Child with Multisystem Inflammatory Syndrome Associated with COVID-19: A Case Report

Children with Coronavirus disease 2019 infection usually have mild symptoms but rarely may present with a life-threatening condition called a multisystem inflammatory syndrome. We report a case of COVID-19-related multisystem inflammatory syndrome in an 8-year-old boy who presented with cardiogenic shock due to acute myocarditis with no features of Kawasaki disease. Cardiogenic shock was refractory to fluids and inotropes. Later, this case was successfully managed with hydrocortisone and intravenous immunoglobulin. Therefore, this case report highlights keeping a lookout for such atypical presentations and early referral to a higher center for timely intervention and aggressive therapy specifically directed against the underlying inflammatory process to ameliorate the outcomes.

Keywords

cardiogenic shock; COVID-19; kawasaki disease; myocarditis; Nepal.

Complications of severe acute respiratory syndrome coronavirus 2 infection in children

PURPOSE OF REVIEW

Although during the initial stages of COVID-19 pandemic, the pediatric population seemed to be less affected, a number of SARS-CoV-2-related manifestations emerged over time, the principal of which is the multisystem inflammatory syndrome in children (MIS-C). Here we provide an update on the main pediatric disorders associated with SARS-CoV-2 infection.

RECENT FINDINGS

MIS-C is novel postinfectious manifestation with clinical features similar to Kawasaki disease and characterized by intense systemic inflammation affecting multiple organs. Many children required intensive care therapy because of circulatory shock, usually of myocardial origin. Appropriate treatment with immunomodulatory therapies led to favorable outcomes in most patients, with recovery of overall health and cardiac dysfunction. In addition to MIS-C, a variety of other complications of COVID-19 in children have been described, including thrombotic events, neurologic manifestations, and chilblain-like lesions. There is still uncertainty about the true prevalence of long COVID in children and its distinction from pandemic-related complaints.

SUMMARY

The experience gained so far with MIS-C and the other SARS-CoV-2-related complications in children and adolescents will facilitate accurate diagnosis and appropriate treatment. Further studies are needed to elucidate the pathophysiology of MIS-C and to determine the real impact of long-COVID in the pediatric age group.

Mild coronary artery dilatation developed in some children with mild COVID-19 but completely regressed within 3 months

Aim

We studied the incidence and time course of any coronary artery changes in children up to 2 years of age who were hospitalised with mild COVID‐19.

Methods

This was a single‐centre prospective study of 29 children (19 males) with a median age of 3 months and interquartile range (IQR) of 1.6–4.3 months. They were admitted to a Greek University hospital for mild COVID‐19 from 1 March to 30 December 2021. Three echocardiographic evaluations were performed at a median (IQR) of 19 (16–24) days, 82 (75–89) days and 172 (163–197) after the first symptoms. The prevalence of coronary artery dilation, regression, and changes was documented.

Results

Coronary artery dilation was present in 3 (10.3%) cases at the first evaluation, with complete regression at the second. Regression was observed in 18/24 (75%) cases with follow‐up data and 9 (31%) demonstrated significant z‐score changes of >2. Coronary artery changes in any segment at any time were documented in 18/29 (62%) of the patients.

Conclusion

Cases of transient and very mild coronary artery dilatation following mild COVID‐19 completely regressed within 3 months. Large‐scale studies are needed to document the extent and time course of coronary artery dilation following paediatric COVID‐19.

Childhood multisystem inflammatory syndrome associated with COVID-19 (MIS-C): Distinct from Kawasaki disease or part of the same spectrum?

One of the most challenging and intriguing phenomena observed during the COVID-19 pandemic has been the multisystem inflammatory syndrome in children (MIS-C). Patients with this condition present with some clinical features similar to those of Kawasaki disease (KD) and display signs and symptoms that are uncommon or rarely occur in this disorder, such as gastrointestinal complaints and myocarditis, often leading to myocardial failure and shock. In addition, patients' age is older than that of children with classic KD. Management is based on administering intravenous immunoglobulin, glucocorticoids, and anakinra in the most severe instances. It is still debated whether MIS-C and KD are different illnesses or represent a disease continuum.

Laboratory parameters between multisystem inflammatory syndrome in children and Kawasaki disease

Multisystem inflammatory syndrome in children (MIS-C) associated with coronavirus disease 2019 (COVID-19) has been described to partially overlap with Kawasaki disease (KD) with regard to clinical symptoms, but they are unlikely to share the same disease entity. We conducted a systematic review and meta-analysis to characterize the laboratory parameters of MIS-C compared with those of KD and Kawasaki disease shock syndrome (KDSS). Databases were searched for studies on laboratory parameters of MIS-C (hematology, inflammatory markers, cardiac markers, and biochemistry) through May 31, 2021. Twelve studies with 3073 participants yielded 969 MIS-C patients. In terms of hematology, MIS-C patients had lower levels of leukocytes, absolute lymphocyte count and platelet count (PLT) than KD patients and had similar absolute neutrophil count (ANC) and hemoglobin (Hb) levels. In terms of inflammatory markers, MIS-C patients had higher levels of C-reactive protein, D-dimer and ferritin than KD patients and had similar levels of procalcitonin and erythrocyte sedimentation rate (ESR). In terms of cardiac markers, MIS-C patients had higher CPK levels than KD patients. The levels of N-terminal pro-brain natriuretic peptide, troponin and aspartate aminotransferase were not significantly different between MIS-C and KD patients. In terms of biochemistry, MIS-C patients had lower levels of albumin, sodium and alanine aminotransferase and higher levels of creatinine than KD patients. In addition, MIS-C patients had lower levels of PLT, Hb and ESR and higher levels of ANC than KDSS patients. Measurement of laboratory parameters might assist clinicians with accurate evaluation of MIS-C and further mechanistic research.

Explanations for 10 of the most puzzling aspects of multisystem inflammatory syndrome and other Kawasaki-like diseases

WHAT IS KNOWN AND OBJECTIVE

An extensively documented multisystem inflammatory syndrome (MIS) has been observed in a small but significant percentage of COVID-19 patients, in some adults but primarily in paediatric patients, and for these patients it is sometimes called MIS-C.

COMMENT

Kawasaki disease has also been observed over the last several decades in patients that tested positive for a variety of very virulent pathogens. Several differences and similarities between MIS-C and Kawasaki disease pathology have been observed. Several puzzling aspects of MIS-C, Kawasaki disease and other Kawasaki-like diseases have been discussed, but not yet explained.

WHAT IS NEW AND CONCLUSION

An explanatory hypothesis has been presented. Using the hypothesis that a transient or permanent inability to quickly phagocytize antigen-antibody immune complexes created by a novel virulent pathogen infection induces a Type III hypersensitivity immune response and the resulting proteinase exposure and expression of new autoantigens are the fundamental steps for MIS and other Kawasaki-like diseases, it is possible to provide straightforward explanations for at least 10 of the most puzzling aspects of these diseases. The validity of the hypothesis itself is also supported by its ability to provide consistent and straightforward explanations for a large number of these disease aspects. Furthermore, these straightforward explanations and the explanatory hypothesis on which they are based also suggest several potential new treatments, which could possibly be more effective than various treatments in current use.

Kawasaki disease mimickers

BACKGROUND

Kawasaki disease (KD) is an acute systemic vasculitis that predominantly affects patients younger than 5 years. In the absence of an available, affordable diagnostic test, detailed clinical history and physical examination are still fundamental to make a diagnosis.

METHODS

We present five representative cases with KD-like presentations: systemic onset juvenile idiopathic arthritis, mycoplasma-induced rash and mucositis, staphylococcal scalded skin syndrome, BCGosis, and the recently described multisystemic inflammatory syndrome in children (MIS-C) associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) virus.

RESULTS

Rash, fever, and laboratory markers of inflammation can be present in several childhood diseases that may mimic KD.

CONCLUSION

The term 'Kawasaki syndrome' instead of 'Kawasaki disease' may be more appropriate. Physicians should consider an alternative diagnosis that may mimic KD, particularly considering MIS-C during the present pandemic, as an aggressive diagnostic and therapeutic approach is needed.

Current Understanding of Multisystem Inflammatory Syndrome (MIS-C) Following COVID-19 and Its Distinction from Kawasaki Disease

PURPOSE OF REVIEW

In this article, I have reviewed current reports that explore differences and similarities between multisystem inflammatory syndrome in children (MIS-C) and other known multisystem inflammatory diseases seen in children, particularly Kawasaki disease.

RECENT FINDINGS

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a human coronavirus causing the COVID-19 disease which emerged in China in December 2019 and spread rapidly to the entire country and quickly to other countries. Currently, there is a pandemic of SARS-CoV-2 infection that results in 20% of patients admitted to hospital with illness, with 3% developing intractable acute respiratory distress syndrome (ARDS) with high mortality. However, pediatric COVID-19 is still reported to be a mild disease, affecting only 8% of children. Pathogenesis in children is comparable to adults. There are suggested impaired activation of IFN-alpha and IFN regulator 3, decreased cell response causing impaired viral defense, yet the clinical course is mild, and almost all children recover from the infection without major complications. Interestingly, there is a subset of patients that develop a late but marked immunogenic response to COVID-19 and develop MIS-C. Clinical features of MIS-C resemble certain pediatric rheumatologic diseases, such as Kawasaki disease (mucocutaneous lymph node syndrome) which affects small-medium vessels. Other features of MIS-C resemble those of macrophage activation syndrome (MAS). However, recent research suggests distinct clinical and laboratory differences between MIS-C, Kawasaki disease, and MAS. Since the start of the SARS-CoV-2 pandemic, MIS-C has become the candidate for the most common cause of acquired heart disease in children.

Systemic and organ-specific immune-related manifestations of COVID-19

Immune-related manifestations are increasingly recognized conditions in patients with COVID-19, with around 3,000 cases reported worldwide comprising more than 70 different systemic and organ-specific disorders. Although the inflammation caused by SARS-CoV-2 infection is predominantly centred on the respiratory system, some patients can develop an abnormal inflammatory reaction involving extrapulmonary tissues. The signs and symptoms associated with this excessive immune response are very diverse and can resemble some autoimmune or inflammatory diseases, with the clinical phenotype that is seemingly influenced by epidemiological factors such as age, sex or ethnicity. The severity of the manifestations is also very varied, ranging from benign and self-limiting features to life-threatening systemic syndromes. Little is known about the pathogenesis of these manifestations, and some tend to emerge within the first 2 weeks of SARS-CoV-2 infection, whereas others tend to appear in a late post-infectious stage or even in asymptomatic patients. As the body of evidence comprises predominantly case series and uncontrolled studies, diagnostic and therapeutic decision-making is unsurprisingly often based on the scarcely reported experience and expert opinion. Additional studies are required to learn about the mechanisms involved in the development of these manifestations and apply that knowledge to achieve early diagnosis and the most suitable therapy.

Multisystem Inflammatory Syndrome in Children: Unique Disease or Part of the Kawasaki Disease Spectrum?

One of the most intriguing and mysterious phenomena observed during the COVID-19 pandemic has been represented by the occurrence of the multisystem inflammatory syndrome in children and adolescents (MIS-C). Patients with this condition have some overlapping signs and symptoms with those of Kawasaki disease (KD), but also display clinical features that are uncommon or less frequent in this illness, such as diarrhea, abdominal pain and myocardial involvement. The sickest patients may develop multiorgan failure and shock, usually due to myocarditis. Management is based on the administration of intravenous immunoglobulin, glucocorticoids and, in the most severe instances, anakinra. It is still debated whether MIS-C and KD represent different illnesses or are part of the same disease spectrum. The aim of the present review is to analyze critically the evidence in favor of the latter hypothesis and to provide the authors' personal interpretation of the relationship between the two conditions.

Serum proteins may facilitate the identification of Kawasaki disease and promote in vitro neutrophil infiltration

Kawasaki disease (KD) usually affects the children younger than 5 years of age and subsequently causes coronary artery lesions (CALs) without timely identification and treatment. Developing a robust and fast prediction method may facilitate the timely diagnosis of KD, significantly reducing the risk of CALs in KD patients. The levels of inflammatory serum proteins dramatically vary during the onsets of many immune diseases, including in KD. However, our understanding of their pathogenic roles in KD is behind satisfaction. The purpose of this study was to evaluate candidate diagnostic serum proteins and the potential mechanism in KD using iTRAQ gel-free proteomics. We enrolled subjects and conducted iTRAQ gel-free proteomics to globally screen serum proteins followed by specific validation with ELISA. Further in vitro leukocyte trans-endothelial model was also applied to investigate the pathogenesis roles of inflammatory serum proteins. We identified six KD protein biomarkers, including Protein S100-A8 (S100A8), Protein S100-A9 (S100A9), Protein S100-A12 (S100A12), Peroxiredoxin-2 (PRDX2), Neutrophil defensin 1 (DEFA1) and Alpha-1-acid glycoprotein 1 (ORM1). They enabled us to develop a high-performance KD prediction model with an auROC value of 0.94, facilitating the timely identification of KD. Further assays concluded that recombinant S100A12 protein treatment activated neutrophil surface adhesion molecules responsible for adhesion to endothelial cells. Therefore, S100A12 promoted both freshly clinically isolated neutrophils and neutrophil-like cells to infiltrate through the endothelial layer in vitro. Finally, the antibody against S100A12 may attenuate the infiltration promoted by S100A12. Our result demonstrated that evaluating S100A8, S100A9, S100A12, PRDX2, DEFA1 and ORM1 levels may be a good diagnostic tool of KD. Further in vitro study implied that S100A12 could be a potential therapeutic target for KD.