Multisystem inflammatory syndrome in children (MIS-C) is an imperative pediatric inflammatory condition closely linked to COVID-19, which garners substantial attention since the onset of the pandemic. Like Kawasaki illness, this condition is characterized by an overactive immune response, leading to symptoms including pyrexia, cardiac and renal complications. To elucidate the pathogenesis of MIS-C and identify potential biomarkers, we conducted an extensive examination of specific cytokines (IL-6, IL-1β, IL-6R, IL-10, and TNF-α) and microRNA (miRNA) expression profiles at various intervals (ranging from 3 to 20 days) in the peripheral blood sample of a severely affected MIS-C patient. Our investigation revealed a gradual decline in circulating levels of IL-6, IL-1β, IL-10, and TNF-α following intravenous immune globulin (IVIG) therapy. Notably, IL-6 exhibited a significant reduction from 74.30 to 1.49 pg./mL, while IL-6R levels remained consistently stable throughout the disease course. Furthermore, we observed an inverse correlation between the expression of hsa-miR-596 and hsa-miR-224-5p and the aforementioned cytokines. Our findings underscore a robust association between blood cytokine and miRNA concentrations and the severity of MIS-C. These insights enhance our understanding of the genetic regulatory mechanisms implicated in MIS-C pathogenesis, offering potential avenues for early biomarker detection and therapy monitoring through miRNA analysis.

BACKGROUND: Transient erythroblastopenia of childhood (TEC) is an acquired, self-limited pure red cell aplasia that usually occurs in children 4 years old and younger. This clinical condition has been priorly described to be linked to numerous viral and immunologic mechanisms. COVID-19, caused by the coronavirus SARS-CoV-2, was initially discovered in China in December 2019. The disease quickly spread worldwide, resulting in pandemic.
METHODS: This manuscript reports a new clinically relevant condition associated to COVID-19, describing a child with clinical and biochemical signs of Pure Red Blood cells aplasia and complete absence of erythroblasts at the bone marrow needle aspiration with signs of erythrophagocytosis, resembling morphological signs such as in hemophagocytic lymphohistiocytosis (HLH), temporally associated to SARS-CoV-2 infection.
CONCLUSIONS: This report highlights a newly described continuum laboratory and clinical spectrum of immune/hematological dysregulations secondary to SARS-CoV-2. SARS-CoV-2 infection-linked TEC has never been described in literature, but, according to our findings, should be considered in all the patients with transient erythroblastopenia without congenital red blood cell abnormalities and serology negative for major infections associated with TEC. This condition must be considered in the same spectrum of MIS-C and the inter-links among the two clinical manifestations, as well as a potential interdependence among them, should be considered in the future.

Multisystem inflammatory syndrome in children (MIS-C) is a disease that made its mark in the early days of the COVID-19 pandemic due to the diverse course and symptoms affecting multiple body systems. It is a condition that develops in pediatric patients about 2-6 weeks after contact with a person infected with the SARS-CoV-2 virus. In many instances, MIS-C has caused multiple organ failure, with particularly severe complications involving the cardiovascular system and manifesting as hypotension, various cardiac arrhythmias, myocarditis or coronary artery lesions resembling those seen in Kawasaki disease. Currently, the incidence of MIS-C is about 1-3 per 1000 children, with a decreasing trend in recent years due to the introduction of immunization against the SARS-CoV-2 virus for children as young as 6 months. In our paper, we present the case of a patient with a severe course of MIS-C with numerous cardiovascular and neurological complications, in whom the symptoms of the disease were managed by administering biological treatment. We also present a review of the literature on the subject, which shows how many different facets this disease can have and that physicians still need to remain alert, as there are cases of severe MIS-C, especially in unvaccinated patients.

Ileocecal intussusception (ICI) is the most common abdominal emergency and cause of intestinal obstruction in young children, carrying a high risk of mortality and morbidity. Enteric viral infectious and inflammatory syndromes are known triggers for intussusception (ileoileal and ileocolic) by causing mesenteric lymphoid hyperplasia that may act as a leading point allowing the bowel to invaginate into itself. Gastrointestinal (GI) symptoms are common in children with coronavirus disease 2019 (COVID-19) infection, with a subset of patients solely having GI complaints at the time of presentation.  COVID-19 as a trigger for intussusception in children has been hypothesized and suggested in multiple cases reported to date, both during the acute phase of illness and as a part of multisystem inflammatory syndrome in children (MIS-C). We present a seven-month-old male who developed ICI and became a diagnostic dilemma due to viral co-infections and the gradual emergence of MIS-C during the hospital stay. We are describing this presentation in an attempt to expand the understanding of the implications of COVID-19 and MIS-C in this young and unique age group.

Multisystem inflammatory syndrome of childhood (MIS-C) is a recently described entity in pediatrics post-COVID-19 pandemic. Hemophagocytic lymphohistiocytosis (HLH) is a clinical syndrome caused by an unregulated proliferation of macrophages as well as T lymphocytes. Both entities can be considered overlapping, although distinct criteria for each can be found in the literature. Herein, we report a patient with MIS-C post-COVID-19 infection, complicated with HLH secondary to Plasmodium falciparum malaria from a blood transfusion.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a serious hyperinflammatory condition associated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Usually, the diagnosis of MIS-C is made by criteria defined by international organizations, which include specific clinical features, laboratory findings, and evidence of SARS-CoV-2 infection. We hereby present a case series of three children. The objective of this case series, involving chart review of medical records of children admitted with MIS-C, is to emphasize that the features of MIS-C may overlap with other conditions.
METHODS: Three children were presented with MIS-C based on World Health Organization (WHO) criteria and given treatment for the same. However, due to persistent symptoms, they were further worked up and diagnosed to have underlying bacterial infections which included liver abscess, enteric fever, or urinary tract infection.
CONCLUSIONS: The criteria for MIS-C may overlap with other conditions, particularly bacterial infection that may lead to overdiagnosis of MIS-C. Therefore, one should be very careful in making an MIS-C diagnosis and other differential diagnoses should be considered when the symptoms persist or worsen.

Pediatric inflammatory, multisystem syndrome temporally associated with SARS-CoV-2 infection (PIMS-TS), also known as a multisystem inflammatory syndrome in children (MIS-C), is diagnosed in children who develop an inadequate inflammatory response after exposure to the SARS-CoV-2 virus. The pathogenesis of the abnormal response of the immune system to a previous SARS-COV-2 infection has not been explained. Similarly, the safety and effectiveness of COVID-19 vaccinations in this group of patients have become the subject of clinical discussion. Presenting experiences from many centers aims to answer this question. We present 4 cases of patients who suffered from PIMS-TS. Three of them were safely vaccinated against COVID-19 after illness. One patient developed PIMS-TS temporarily associated with COVID-19 vaccination. We also collected and discussed data from other centers.

Kawasaki disease (KD) is an acute medium-vessel vasculitis, mainly affecting infants older than six months and children under five years. It predisposes to the development of coronary artery aneurysms and constitutes the leading cause of acquired heart disease in children. Its diagnosis is based on clinical criteria, namely, fever lasting for ≥ five days together with at least four of the five principal clinical features of the disease. Occasionally, children with KD present with fever, but they fulfill only some of the five principal criteria, and this is described as incomplete KD. Furthermore, \"atypical\" KD is a term that is usually used for cases that appear with rather unusual clinical manifestations, which complicate clinical judgment and may delay diagnosis and treatment. In this case series, we present four cases of KD with rather unusual clinical features: a five-year-old boy with lobar pneumonia, a six-year-old girl with orange-brown chromonychia appearing on the 10th day of the disease, a 2.5-month-old infant with prolonged fever and urinary tract infection, and an 18-month-old infant with refractory KD and high suspicion of multisystem inflammatory syndrome in children (MIS-C). A literature review on the unusual manifestations of atypical KD was performed to identify clinical findings that must alert the clinician to consider this clinical entity.

At 23 days of life a neonate presented to the emergency room with crying and decreased oral intake. His parents were positive to SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), but he turned out negative. After one week he was admitted to NICU (neonatal intensive care unit) for respiratory failure, and nasopharyngeal swab (PCR test: polymerase chain reaction test) was positive for SARS-CoV-2. On examination the child had fever, tachy-dyspnea, reduced oxygen saturation, tachycardia, abdominal distension and tenderness, irritability and hypertonia. Blood exam showed respiratory acidosis, lymphocytopenia, hypoalbuminemia and coagulopathy; CRP (C reactive protein), procalcitonin, D-dimer, ferritin and NT-proBNP (N-terminal prohormone of brain natriuretic peptide) were elevated. Chest X-ray revealed bilateral interstitial infi ltration and abdomen ultrasound a thin fl uid effusion; echocardiography was normal. SARS-CoV-2 PCR tests on CSF (cerebrospinal fluid) and stool were also positive. He was started on non-invasive intermittent positive pressure respiratory ventilation, treated with antibiotic therapy, methylprednisolone, intravenous immunoglobulins, and antiplatelet therapy. Rapid clinical improvement was seen with remission of fever after eight days. The child complicated with bacterial super-infection presenting as pleural empyema. As presented in our case, it is not always easy to differentiate between severe forms of COVID-19 and MIS-C. Due to the rarity of these presentations in neonates, multicentric collaboration is needed to identify the specifi c characteristics of the two forms, better defi ne diagnostic criteria, and treatment options.

BACKGROUND: In multisystem inflammatory syndrome (MIS-C), children typically present high-grade fever, gastrointestinal symptoms, Kawasaki-like symptoms, and even a toxic shock-like syndrome days to weeks after recovering from SARS-CoV-2 infection. It is important to raise awareness of this condition in order to have early diagnosis and immediate treatment of patients. We have, herein, reported 44 cases of MIS-C with various risk factors and symptoms. Furthermore, we have emphasized the efficacy of experience in treating children with MIS-C with high-dose corticosteroids as an alternative to immunoglobulin in low-income countries.
METHODS: We conducted a targeted survey of MIS-C from early May 2020 to October 2022 on 44 children and adolescents with characteristics of multisystem inflammatory syndrome admitted to the pediatric department of the university hospital center in Oujda, Morocco, to which patients diagnosed with MIS-C were referred. The case definition included six criteria: serious illness leading to hospitalization, age under 18 years, fever of at least 24 hours, laboratory evidence of inflammation, multi-organ involvement, biological inflammatory syndrome, and evidence of coronavirus infection based on polymerase chain reaction, antibody testing or exposure to people with COVID-19 in the past month. The criteria used to diagnose myocarditis were impaired left ventricular function, central mitral leak, and elevation of BNP or pro-BNP. Coronary involvement was assessed by the z-score and the criteria for its presence was a z-score equal to or greater than 2.5.
RESULTS: Our study included 44 children and adolescents with MIS-C in our hospital, with male predominance (79%) and a median age of six years. Cardiovascular involvement was present in 91%, mucocutaneous in 78%, gastrointestinal in 70%, hematologic in 84%, and respiratory in 2% of patients. Coronary abnormalities (z-score ≥ 2.5) were documented in 21 cases (48%). Glucocorticoids were frequently used in comparison to immunoglobulin, which were uncommonly available and expensive.
CONCLUSIONS: The therapeutic protocol that was adopted was high doses of short-term prednisone (Cortancyl) at 4mg/kg/day for 4 days. Favorable outcome was noted in all patients over a 2-year period.