MIS-C: post-infectious syndrome or persistent infection?

Evaluation of 601 children with multisystem inflammatory syndrome (Turk MISC study)

PURPOSE

Due to its link with the 2019 coronavirus, the multisystem inflammatory syndrome in children (MISC) has garnered considerable international interest. The aim of this study, in which MISC patients were evaluated multicenter, and the data of the third period of the Turk-MISC study group, to compare the clinical and laboratory characteristics and outcomes of MISC patients who did and did not require admission to an intensive care unit (ICU).

METHODS

This retrospective multicenter observational study was carried out between June 11, 2021, and January 01, 2022. The demographics, complaints, laboratory results, system involvements, and outcomes of the patients were documented.

RESULTS

A total of 601 patients were enrolled; 157 patients (26.1%) required hospitalization in the intensive care unit (ICU). Median age was 8 years (interquartile range (IQR) 4.5-11.3 years. The proportion of Kawasaki disease-like features in the ICU group was significantly higher than in the non-ICU group (56.1% vs. 43.2% p = 0.006). The ICU group had considerably lower counts of both lymphocytes and platelets (lymphocyte count 900 vs. 1280 cells × μL, platelet count 153 vs. 212 cells × 103/ μL, all for p< 0.001). C-reactive protein, procalcitonin, and ferritin levels were significantly higher in the ICU group (CRP 164 vs. 129 mg/L, procalcitonin 9.2 vs. 2.2 μg/L, ferritin 644 vs. 334 μg/L, all for p< 0.001). Being between ages 5-12 and older than 12 increased the likelihood of hospitalization in the ICU by four [95% confidence intervals (CI)1.971-8.627] and six times (95% CI 2.575-14.654), respectively, compared to being between the ages 0-5. A one-unit increase in log D-dimer (µg/L) and log troponin (ng/L) was also demonstrated to increase the need for intensive care by 1.8 (95% CI 1.079-3.233) and 1.4 times (95% CI 1.133-1.789), respectively.     Conclusion: By comparing this study to our other studies, we found that the median age of MISC patients has been rising. Patients requiring an ICU stay had considerably higher levels of procalcitonin, CRP, and ferritin but significantly lower levels of lymphocyte and thrombocyte. In particular, high levels of procalcitonin in the serum might serve as a valuable laboratory marker for anticipating the need for intensive care.

WHAT IS KNOWN

• Lymphopenia and thrombocytopenia were an independent predictor factors in patients with MISC who needed to stay in intensive care unit. • The possibility of the need to stay in the intensive care unit in patients with MISC who had Kawasaki disease-like findings was controversial compared with those who did not.

WHAT IS NEW

• A one-unit increase log D dimer and log troponin was demonstrated to require for intensive care unit by 1.8 and 1.4 times, respectively. • Serum procalcitonin levels had the best performance to predict stay in the intensive care unit stay.

Epidemiology, Clinical Features, and Outcomes of Multisystem Inflammatory Syndrome in Children (MIS-C) and Adolescents—a Live Systematic Review and Meta-analysis

Purpose of Review

A multisystem inflammatory condition occurring in children and adolescents with COVID-19 has become increasingly recognized and widely studied globally. This review aims to investigate and synthesize evolving evidence on its clinical characteristics, management, and outcomes in pediatric patients.

Recent Findings

We retrieved data from PubMed, EMBASE, Cochrane Library, WHO COVID-19 Database, Google Scholar, and preprint databases, covering a timeline from December 1, 2019, to July 31, 2021. A total of 123 eligible studies were included in the final descriptive and risk factor analyses. We comprehensively reviewed reported multisystem inflammatory syndrome in children (MIS-C) cases from published and preprint studies of various designs to provide an updated evidence on epidemiology, clinical, laboratory and imaging findings, management, and short-term outcomes. Latest evidence suggests that African black and non-Hispanic white are the two most common ethnic groups, constituting 24.89% (95% CI 23.30–26.48%) and 25.18% (95% CI 23.51–26.85%) of the MIS-C population, respectively. Typical symptoms of MIS-C include fever (90.85%, 95% CI 89.86–91.84%), not-specified gastrointestinal symptoms (51.98%, 95% CI 50.13–53.83%), rash (49.63%, 95% CI 47.80–51.47%), abdominal pain (48.97%, 95% CI 47.09–50.85%), conjunctivitis (46.93%, 95% CI 45.17–48.69%), vomiting (43.79%, 95% CI 41.90–45.68%), respiratory symptoms (41.75%, 95% CI 40.01–43.49%), and diarrhea (40.10%, 95% CI 38.23–41.97%). MIS-C patients are less likely to develop conjunctivitis (OR 0.27, 95% CI 0.11–0.67), cervical adenopathy (OR 0.21, 95% CI 0.07–0.68), and rash (OR 0.44, 95% CI 0.26–0.77), in comparison with Kawasaki disease patients. Our review revealed that the majority of MIS-C cases (95.21%) to be full recovered while only 2.41% died from this syndrome. We found significant disparity between low- and middle-income countries and high-income countries in terms of clinical outcomes.

Summary

MIS-C, which appears to be linked to COVID-19, may cause severe inflammation in organs and tissues. Although there is emerging new evidence about the characteristics of this syndrome, its risk factors, and clinical prognosis, much remains unknown about the causality, the optimal prevention and treatment interventions, and long-term outcomes of the MIS-C patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40124-022-00264-1.

Pathogenesis and treatment of cytokine storm in COVID-19

COVID-19 is a viral infection caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that killed a large number of patients around the world. A hyperinflammatory state resulting in a cytokine storm and adult respiratory distress syndrome seems to be the major cause of the death. Many mechanisms have been suggested in the pathogenesis of COVID-19 associated cytokine storm (COVID-CS). Insufficient viral clearance and persistence of a strong cytokine response despite inadequate antiviral immunity seem to be the main mechanisms underlying the pathogenesis. The diagnosis of COVID-19 is based on relatively constant clinical symptoms, clinical findings, laboratory tests, and imaging techniques, while the diagnosis of COVID-CS is a rather dynamic process, based on evolving or newly emerging findings during the clinical course. Management of COVID-19 consists of using antiviral agents to inhibit SARS-CoV-2 replication and treating potential complications including the cytokine storm together with general supportive measures. COVID-CS may be treated using appropriate immunosuppressive and immunomodulatory drugs that reduce the level of inappropriate systemic inflammation, which has the potential to cause organ damage. Currently corticosteroids, IL-6 blockers, or IL-1 blockers are most widely used for treating COVID-CS.