Case report: Multisystem inflammatory syndrome in children associated with COVID-19, macrophage activation syndrome, and incomplete Kawasaki disease.

Background: Multisystem inflammatory syndrome in children (MIS-C), is a severe complication of coronavirus disease 2019 (COVID-19), characterized by persistent fever, systemic inflammatory response, and organ failure. MIS-C with a history of COVID-19 may share clinical features with other well-defined syndromes such as macrophage activation syndrome, Kawasaki disease, hemophagocytic syndrome and toxic shock syndrome. Case 1: An 11-year-old male with a history of hypothyroidism and precocious puberty with positive antibody test for COVID-19 was admitted for fever, poor general condition, severe respiratory distress, refractory shock, and multiple organ failure. His laboratory examination showed elevated inflammatory parameters, and bone marrow aspirate showed hemophagocytosis. Case 2: A 13-year-old male with a history of attention deficit hyperactivity disorder and cognitive delay presented clinical manifestations of Kawasaki disease, fever, conjunctival congestion, exanthema, and hyperemia in oral mucosa, tongue, and genitals, with refractory shock and multiple organ failure. Reverse transcriptase polymerase chain reaction (RT-PCR) and antibodies for COVID-19 were negative, inflammation parameters were elevated, and bone marrow aspirate showed hemophagocytosis. Patients required intensive care with invasive mechanical ventilation, vasopressor support, intravenous gamma globulin, systemic corticosteroids, low molecular weight heparin, antibiotics, and monoclonal antibodies and, patient 2 required renal replacement therapy. Conclusions: Multisystemic inflammatory syndrome in children can have atypical manifestations, and identifying them early is very important for the timely treatment and prognosis of patients.

MIS-C is likely to be distinct from Kawasaki disease based on current studies: a narrative review

Background and Objective: Children with SARS-CoV-2 infection were paid little attention to during the early stages of the outbreak because of low morbidity as well as mild clinical symptoms. Since late April 2020, reports regarding Kawasaki-like syndrome and hyperinflammatory response in children associated with COVID-19 have rapidly emerged. Till now, no certain relationship between multisystem inflammatory syndrome in Children (MIS-C) and Kawasaki Disease (KD) has been determined, which should be explored through continuous study. Methods: In order to synthesize key findings for the objectives of this review, we searched English literature published up to November 16, 2020 using PubMed with the following keywords: Kawasaki disease 2020, Kawasaki-like disease, MIS-C, PIMS, PMIS and PIMS-TS. Key Content and Findings: Based on current researches, KD is regarded as an immune disorder induced by multiple unidentified pathogens, while MIS-C is confirmed to be associated with the infection of COVID-19. In addition, KD is popular in East Asian children under 3 years old, while MIS-C is reported more in older adolescents from Europe and North America. On the basis of multiple cohort studies, gastrointestinal symptoms, mechanical ventilation and inotropic support are more common in MIS-C. Instead, coronary arterial damage is more pronounced in KD. Moreover, the treatment regimen for MIS-C is more aggressive than KD because the cytokine storm is more violent and lasting. Conclusions: MIS-C is likely to be a distinct immunopathogenic illness associated with SARS-CoV-2 based on current studies, which could be used as a reference to help us better understand KD. In addition, MIS-C is an emerging syndrome for pediatricians, so the lack of relevant knowledge may result in under-diagnosis. Some individuals may fulfill full or partial criteria for KD but all should be reported if they meet the case definition for MIS-C. © 2022 AME Publishing Company. All right reserved.

Erythema and Induration of Bacillus Calmette-Guérin Scar Associated With Multisystem Inflammatory Syndrome in Children in Japan: A Case Report.

Multisystem Inflammatory Syndrome in Children (MIS-C) is a rare febrile disorder with multisystem organ involvement temporally associated with coronavirus 2019 infection (COVID-19) and frequently exhibits features mimicking Kawasaki disease (KD), another febrile disorder in children. The pathogenesis and the full clinical spectrum of MIS-C is poorly understood: It is still unclear whether MIS-C and KD are different syndromes or represent a common spectrum. The erythema and induration of Bacillus Calmette-Guérin (BCG) scar is one of the characteristic findings of KD, and is useful for the diagnosis in countries where BCG vaccination is mandated in infancy. Furthermore, such findings in BCG scar were also reported after SARS-CoV-2 vaccination, which may be related to molecular mimicry. However, there are no reports of changes at the BCG scar in MIS-C cases. Here, we report a case of MIS-C in a 3-year-old Hispanic boy in Japan, with erythema and induration at the BCG scar. The patient received BCG vaccination at 16 months of age in Japan. Four weeks before the onset, he had positive polymerase chain reaction (PCR) results for SARS-CoV-2 following household outbreak, although he was asymptomatic. He presented with fever and gastrointestinal symptoms, followed by the appearance of all six principal findings of complete KD. He exhibited congestive heart failure, following intravenous immunoglobulin (IVIG) therapy. He was diagnosed with MIS-C based on characteristic mucocutaneous and gastrointestinal symptoms, decreased cardiac function, and coagulopathy, in addition to laboratory data consistent with MIS-C. The BCG finding was present from the early stage of the disease. The patient was refractory to two doses of IVIGs, and the third IVIG plus prednisolone resulted in defervescence and improvement in heart failure. No coronary involvement was observed. This is the first case of erythema and induration at the BCG scar associated with MIS-C accompanied by KD features, which may give clinical and mechanistic insights in the understanding of the disease. Since the full spectrum of MIS-C is still evolving and both of them are syndromes with overlapped clinical features, further studies are warranted for deep phenotyping of MIS-C with KD features relative to KD in countries with mandatory BCG programs in infancy.

A Case Report of Pediatric Kawasaki Disease and COVID-19 Association

Introduction: As COVID-19 spreads rapidly all over the world and nations struggle to control it, the novel presentations of SARS-CoV-2 infection and its possible triggering role for other diseases in pediatrics concern clinicians in frontlines. Case Presentation: We describe a 10-year-old child diagnosed with COVID-19 infection and concurrent Kawasaki disease. He pre-sented with prolonged fever and conjunctivitis. His initial echocardiogram showed coronary artery dilation in RCA. He was treated with IVIG and aspirin as per guidelines and discharged 48 hours after the completion of IVIG and diminishing fever. His follow-up echocardiogram showed improvement in a two weeks’ interval while he was quarantined in the meantime and showed no respiratory complications. Conclusions: In conclusion, we think that there might be a correlation between COVID-19 infection and hyperinflammatory condi-tions, like Kawasaki disease. Further investigations are needed to enlighten the complications caused by COVID-19 infection, espe-cially in pediatrics. In addition, we emphasize follow-up visits (in person or long-distance) in pediatrics presenting with inflammatory symptoms. © 2020, Author(s).

Upregulation of type 1 conventional dendritic cells implicates antigen cross-presentation in multisystem inflammatory syndrome.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is an acute, febrile, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-associated syndrome, often with cardiohemodynamic dysfunction. Insight into mechanism of disease is still incomplete. OBJECTIVE: Our objective was to analyze immunologic features of MIS-C patients compared to febrile controls (FC). METHODS: MIS-C patients were defined by narrow criteria, including having evidence of cardiohemodynamic involvement and no macrophage activation syndrome. Samples were collected from 8 completely treatment-naive patients with MIS-C (SARS-CoV-2 serology positive), 3 patients with unclassified MIS-C-like disease (serology negative), 14 FC, and 5 MIS-C recovery (RCV). Three healthy controls (HCs) were used for comparisons of normal range. Using spectral flow cytometry, we assessed 36 parameters in antigen-presenting cells (APCs) and 29 in T cells. We used biaxial analysis and uniform manifold approximation and projection (UMAP). RESULTS: Significant elevations in cytokines including CXCL9, M-CSF, and IL-27 were found in MIS-C compared to FC. Classic monocytes and type 2 dendritic cells (DCs) were downregulated (decreased CD86, HLA-DR) versus HCs; however, type 1 DCs (CD11c+CD141+CLEC9A+) were highly activated in MIS-C patients versus FC, expressing higher levels of CD86, CD275, and atypical conventional DC markers such as CD64, CD115, and CX3CR1. CD169 and CD38 were upregulated in multiple monocyte subtypes. CD56dim/CD57-/KLRGhi/CD161+/CD38- natural killer (NK) cells were a unique subset in MIS-C versus FC without macrophage activation syndrome. CONCLUSION: Orchestrated by complex cytokine signaling, type 1 DC activation and NK dysregulation are key features in the pathophysiology of MIS-C. NK cell findings may suggest a relationship with macrophage activation syndrome, while type 1 DC upregulation implies a role for antigen cross-presentation.

Acute Appendicitis Associated With Kawasaki Disease: Case Report and Review of the Literature.

Acute appendicitis is a rare complication of Kawasaki disease in the setting of the absence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We experienced a rare case of acute appendicitis associated with Kawasaki disease. The patient is a six-year-old male who was brought to the emergency department by his mother with a pruritic rash, nausea, vomiting, and abdominal pain. Given fever, tenderness in the right lower quadrant on physical examination, leukocytosis with bandemia, and a non-compressible and dilated appendix on ultrasound, he was diagnosed with acute appendicitis and was treated with a laparoscopic appendectomy. He developed persistent fevers after surgery with new lip swelling, mucositis, and bilateral conjunctival injection. Kawasaki disease was suspected and intravenous gammaglobulin and aspirin were administrated. He made a full recovery. This case suggests that careful examination is needed for accurate diagnosis, especially in patients with postoperative persistent fever without signs of intra-abdominal complications. We performed a PubMed literature search and reviewed eight cases of appendicitis associated with Kawasaki disease. Of note, this case was seen in 2018 before the SARS-CoV-2 pandemic and the description of multisystem inflammatory syndrome in children (MIS-C).

Differences and similarities of multisystem inflammatory syndrome in children, Kawasaki disease and macrophage activating syndrome due to systemic juvenile idiopathic arthritis: a comparative study.

To compare the clinical and laboratory findings of multisystem inflammatory syndrome in children (MIS-C), patients with Kawasaki disease (KD) and with macrophage activating syndrome due to systemic juvenile idiopathic arthritis (sJIA-MAS) on real-life data. Patients diagnosed with MIS-C, KD, and sJIA-MAS from 12 different centers in Turkey who were followed for at least 6 months were included in the study. Demographic, clinical, and laboratory findings of all patients were analyzed. A total of 154 MIS-C, 59 KD, and 31 sJIA-MAS patients were included. The median age of patients with MIS-C were higher than those with KD while lower than those with sJIA-MAS (8.2, 3, 12 years, respectively). Myalgia (39.6%), cardiac (50.6%), gastrointestinal (72.7%), and neurological (22.1%) involvements were more common in patients with MIS-C compared to others. MIS-C patients had lower levels of lymphocyte (950 vs 1700 cells/µl) and thrombocyte (173,000 vs 355,000 cells/µl) counts and higher pro-BNP (1108 vs 55 pg/ml) levels than KD. Ferritin levels were higher in patients with MIS-C compared to patients with KD while they were lower than patients with sJIA-MAS (440, 170, 10,442 ng/ml, respectively). Patients with MIS-C had a shorter duration of hospitalization than sJIA-MAS (p = 0.02) while they required intensive care unit admission more frequently (55 vs 8 patients, p < 0.001). The median MAS/sJIA score of MIS-C patients was - 1.64 (- 5.23 to 9.68) and the median MAS/sJIA score of sJIA-MAS patients was -2.81 ([- 3.79] to [- 1.27]). MIS-C patients displayed certain differences in clinical and laboratory features when compared to KD and sJIA-MAS. Definition of the differences and similarities between MIS-C and the other intense inflammatory syndromes of childhood such as KD and MAS will help the clinicians while making timely diagnosis.

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.

Prevalence and Clinical Characteristics of SARS-CoV-2 Confirmed and Negative Kawasaki Disease Patients During the Pandemic in Spain.

Introduction: COVID-19 has a less severe course in children. In April 2020, some children presented with signs of multisystem inflammation with clinical signs overlapping with Kawasaki disease (KD), most of them requiring admission to the pediatric intensive care unit (PICU). This study aimed to describe the prevalence and clinical characteristics of KD SARS-CoV-2 confirmed and negative patients during the pandemic in Spain. Material and Methods: Medical data of KD patients from January 1, 2018 until May 30, 2020 was collected from the KAWA-RACE study group. We compared the KD cases diagnosed during the COVID-19 period (March 1-May 30, 2020) that were either SARS-CoV-2 confirmed (CoV+) or negative (CoV-) to those from the same period during 2018 and 2019 (PreCoV). Results: One hundred and twenty-four cases were collected. There was a significant increase in cases and PICU admissions in 2020 (P-trend = 0.001 and 0.0004, respectively). CoV+ patients were significantly older (7.5 vs. 2.5 yr) and mainly non-Caucasian (64 vs. 29%), had incomplete KD presentation (73 vs. 32%), lower leucocyte (9.5 vs. 15.5 × 109) and platelet count (174 vs. 423 × 109/L), higher inflammatory markers (C-Reactive Protein 18.5vs. 10.9 mg/dl) and terminal segment of the natriuretic atrial peptide (4,766 vs. 505 pg/ml), less aneurysm development (3.8 vs. 11.1%), and more myocardial dysfunction (30.8 vs. 1.6%) than PreCoV patients. Respiratory symptoms were not increased during the COVID-19 period. Conclusion: The KD CoV+ patients mostly meet pediatric inflammatory multisystem syndrome temporally associated with COVID-19/multisystem inflammatory syndrome in children criteria. Whether this is a novel entity or the same disease on different ends of the spectrum is yet to be clarified.

Adult Inflammatory Multi-System Syndrome Mimicking Kawasaki Disease in a Patient With COVID-19.

We describe a 46-year-old male with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection who presented as a Kawasaki-like syndrome with features including prolonged fever, bilateral conjunctivitis, oral mucosal swelling, diffuse erythematous rash, cervical and hilar lymphadenopathy, as well as cardiovascular complications and multi-organ failure. There are several reports of a similar clinical entity mimicking Kawasaki disease (KD) in the pediatric population, which has been termed Pediatric Inflammatory Multisystem Syndrome Temporally Associated with SARS-CoV-2 (PIMS-TS) by the Royal College of Pediatric and Child Health. To our knowledge, to date, there has been only one case report of COVID-19 presenting as KD in an adult patient.