The clinical course of CCHF among children seems to be milder than in adults. Tonsillopharyngitis is a common symptom among children with CCHF.

In Turkey, 2009 H1N1 infection caused high mortality and PICU admission due to severe respiratory illness and complications, especially in children with an underlying condition.

Using ASEX in the detection of SD in PD might be important in directing patients to further evaluation and treatment.

Aims Recently, multisystem inflammatory syndrome in children (MIS‐C) has been recognized in association with coronavirus disease 2019 as a cytokine storm syndrome. MIS‐C presents with symptoms similar to Kawasaki disease and macrophage activation syndrome (MAS). We aimed to better understand this cytokine storm syndrome by comparing the initial laboratory findings of MIS‐C and MAS. Methods Patients who were diagnosed with MAS due to systemic juvenile idiopathic arthritis in our clinic between March 2002 and November 2020 and with MIS‐C between 20 September and 20 October 2020 were enrolled into the study. The medical files of all patients were reviewed retrospectively. Results A total of 13 MAS (9 boys, 4 girls) and 26 MIS‐C (16 boys,10 girls) patients were included in the study. Hemoglobin, absolute neutrophil and lymphocyte counts, C‐reactive protein (CRP), ferritin, fibrinogen and lactate dehydrogenase (LDH) levels showed significant differences between the two groups (P < 0.05). Patients with MAS had lower hemoglobin (10.10 g/dL) and fibrinogen (2.72 g/dL), but higher ferritin (17 863 mg/dL) and LDH (890.61 U/L) at the time of diagnosis. Patients with MIS‐C had higher absolute neutrophil count (12 180/mm3) and CRP (194.23 mg/dL) values, but lower absolute lymphocyte count (1140/mm3) at the time of diagnosis. Left ventricle ejection fraction was significantly lower in the MIS‐C group in echocardiographic evaluation (P < 0.001). Conclusion Ferritin, hemoglobin, LDH, and fibrinogen levels were significantly changed in MAS compared with MIS‐C. However, patients with MIS‐C have more severe signs than MAS, such as cardiac involvement.

Cardiac involvement is a common and serious problem in multisystem inflammatory syndrome in children (MIS-C). Echocardiographic evaluation of systolic and diastolic function by traditional, tissue Doppler and three-dimensional (3D) echocardiography was performed in consecutive 50 MIS-C patients during hospitalization and age-matched 40 healthy controls. On the day of worst left ventricular (LV) systolic function (echo-1), all left and right ventricular systolic function parameters were significantly lower ( p < 0.001), E/A ratio was significantly lower, and averaged E/e′ ratio was significantly higher (median 1.5 vs. 1.8, p < 0.05; 8.9 vs. 6.3, p < 0.001 respectively) in patients compared to control. Patients were divided into 2 groups according to 3D LV ejection fraction (LVEF) on the echo-1: Group 1; LVEF < 55%, 26 patients, and group 2; LVEF ≥ 55%, 24 patients. E/e′ ratio was significantly higher in group 1 than group 2 and control at discharge (median 7.4 vs. 6.9, p = 0.005; 7.4 vs. 6.3, p < 0.001 respectively). Coronary ectasia was detected in 2 patients (z score: 2.53, 2.6 in the right coronary artery), and resolved at discharge. Compared with group 2, group 1 had significantly higher troponin-I (median 658 vs. 65 ng/L; p < 0.001), NT-pro BNP (median 14,233 vs. 1824 ng/L; p = 0.001), procalcitonin (median 10.9 vs. 2.1 µg/L; p = 0.009), ferritin (median 1234 vs. 308 µg/L; p = 0.003). The most common findings were ventricular systolic dysfunction recovering during hospitalization, and persisting LV diastolic dysfunction in the reduced LVEF group at discharge. Coronary artery involvement was rare in the acute phase of the disease. Also, in MIS-C patients, the correlation between LV systolic dysfunction and markers of inflammation and cardiac biomarkers should be considered. Supplementary Information The online version contains supplementary material available at 10.1007/s00246-021-02738-3.