Distinguishing Incomplete Kawasaki and Nonsevere Multisystem Inflammatory Syndrome in Children.

OBJECTIVES: Characterizing inflammatory syndromes during the coronavirus disease 2019 pandemic was complicated by recognition of multisystem inflammatory syndrome in children (MIS-C), contemporaneous with episodes of Kawasaki disease. We hypothesized a substantial overlap between the 2 and assessed the performance of an MIS-C likelihood score in differentiating inpatients with nonsevere MIS-C from prepandemic incomplete Kawasaki disease (iKD) without coronary involvement. METHODS: A retrospective review of inpatient records was conducted; the nonsevere MIS-C cohort (March 2020-February 2021) met the 2023 definition for MIS-C; the iKD cohort (January 2018-January 2019) met the American Heart Association criteria for iKD without coronary involvement. We applied the likelihood score to both cohorts. We estimated the percent of children with iKD who could have met the clinical criteria of the MIS-C, had they presented in 2023. RESULTS: The 68 children in the nonsevere MIS-C cohort were older (8 vs 4 years, P < .001) than the 28 children in the iKD cohort. Those in the nonsevere MIS-C cohort had higher rates of thrombocytopenia (P < .001) and lymphopenia (P = .021); those in the iKD cohort had higher rates of pyuria (P < .001). Twenty-four (86%) children in the iKD cohort met the 2023 MIS-C definition. The scoring system correctly predicted 71% to 74% children with their respective clinical diagnoses. CONCLUSIONS: Though there was considerable clinical overlap, thrombocytopenia, lymphopenia, and the absence of pyuria were the most helpful parameters to distinguish children with nonsevere MIS-C from those with iKD.

Short-term Outcomes of Corticosteroid Monotherapy in Multisystem Inflammatory Syndrome in Children.

Importance: Optimal agents and duration of primary treatment for multisystem inflammatory syndrome in children (MIS-C) remain unclear. Objective: To compare short-term patient outcomes based on initial treatment with corticosteroids, intravenous immunoglobulin (IVIG), or both. Design, Setting, and Participants: This retrospective cohort study included patients in a tertiary-care pediatric hospital system who had MIS-C per the Centers for Disease Control and Prevention case definition during the period March 2020 to February 2021. Exposures: Immunomodulatory therapy within the first 24 hours (patients in the intensive care unit [ICU]) or 48 hours (non-ICU patients): corticosteroids alone, IVIG alone, and IVIG plus corticosteroids. Main Outcomes and Measures: Primary outcome was failure of initial therapy, defined as therapy escalation due to fever or worsening or lack of improvement of laboratory, cardiac, or noncardiac clinical factors after 24 hours (ICU patients) or 48 hours (non-ICU patients) from time of therapy initiation, per clinician assessment. Secondary outcomes included presence of complications, cardiovascular outcomes, fever duration, length of hospital and ICU stays, corticosteroid use duration, and need for readmission. Results: Among 228 eligible patients, 215 patients were included in the univariate analysis; median age was 8 years, and 135 (62.8%) were boys. There were 69 patients in the corticosteroids group, 31 patients in the IVIG group, and 115 patients in the IVIG plus corticosteroids group. Patients in the corticosteroids group had milder disease at presentation. After propensity score weighting including 179 patients (68 in the corticosteroids group and 111 in the IVIG plus corticosteroids group), rates of initial treatment failure were similar between groups. Among patients whose initial treatment failed, treatment failure in the IVIG plus corticosteroids group was more likely to be based on laboratory parameters (odds ratio [OR], 1.96; 95% CI, 1.07-3.60) and less likely to be based on cardiovascular markers (OR, 0.39; 95% CI, 0.2-0.76), per clinician assessment. Patients in the IVIG plus corticosteroids group had a longer median inpatient stay (6 vs 5 days; P = .001) and longer median corticosteroid course duration (10 vs 5 days; P = .04) compared with the corticosteroids group. Forty-nine patients (71% of 69 in the corticosteroids group) recovered after receiving corticosteroid monotherapy for 10 days or less. Conclusions and Relevance: Corticosteroid monotherapy is a reasonable management option for a subset of patients with MIS-C, particularly those with mild disease.

Serologic and Cytokine Signatures in Children With Multisystem Inflammatory Syndrome and Coronavirus Disease 2019.

BACKGROUND: The serologic and cytokine responses of children hospitalized with multisystem inflammatory syndrome (MIS-C) vs coronavirus disease 2019 (COVID-19) are poorly understood. METHODS: We performed a prospective, multicenter, cross-sectional study of hospitalized children who met the Centers for Disease Control and Prevention case definition for MIS-C (n = 118), acute COVID-19 (n = 88), or contemporaneous healthy controls (n = 24). We measured severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike receptor-binding domain (RBD) immunoglobulin G (IgG) titers and cytokine concentrations in patients and performed multivariable analysis to determine cytokine signatures associated with MIS-C. We also measured nucleocapsid IgG and convalescent RBD IgG in subsets of patients. RESULTS: Children with MIS-C had significantly higher SARS-CoV-2 RBD IgG than children with acute COVID-19 (median, 2783 vs 146; P < .001), and titers correlated with nucleocapsid IgG. For patients with MIS-C, RBD IgG titers declined in convalescence (median, 2783 vs 1135; P = .010) in contrast to patients with COVID-19 (median, 146 vs 4795; P < .001). MIS-C was characterized by transient acute proinflammatory hypercytokinemia, including elevated levels of interleukin (IL) 6, IL-10, IL-17A, and interferon gamma (IFN-γ). Elevation of at least 3 of these cytokines was associated with significantly increased prevalence of prolonged hospitalization ≥8 days (prevalence ratio, 3.29 [95% CI, 1.17-9.23]). CONCLUSIONS: MIS-C was associated with high titers of SARS-CoV-2 RBD IgG antibodies and acute hypercytokinemia with IL-6, IL-10, IL-17A, and IFN-γ.

Retropharyngeal Edema and Neck Pain in Multisystem Inflammatory Syndrome in Children (MIS-c).

We defined the prevalence of neck pain, trismus, or dysphagia (28.4%) and retropharyngeal edema (2.9%) among 137 patients with multisystem inflammatory syndrome in children (MIS-c). Retropharyngeal edema or phlegmon has been documented radiologically in at least 9 children. Symptoms of neck inflammation are common in MIS-c.

Management and Outcomes in Children with Third-Generation Cephalosporin-Resistant Urinary Tract Infections.

BACKGROUND: Third-generation cephalosporin-resistant urinary tract infections (UTIs) often have limited oral antibiotic options with some children receiving prolonged parenteral courses. Our objectives were to determine predictors of long parenteral therapy and the association between parenteral therapy duration and UTI relapse in children with third-generation cephalosporin-resistant UTIs. METHODS: We conducted a multisite retrospective cohort study of children <18 years presenting to acute care at 5 children's hospitals and a large managed care organization from 2012 to 2017 with a third-generation cephalosporin-resistant UTI from Escherichia coli or Klebsiella spp. Long parenteral therapy was ≥3 days and short/no parenteral therapy was 0-2 days of concordant parenteral antibiotics. Discordant therapy was antibiotics to which the pathogen was non-susceptible. Relapse was a UTI from the same organism within 30 days. RESULTS: Of the 482 children included, 81% were female and the median age was 3.3 years (interquartile range: 0.8-8). Fifty-four children (11.2%) received long parenteral therapy (median duration: 7 days). Predictors of long parenteral therapy included age <2 months (adjusted odds ratio [aOR] 67.3; 95% confidence interval [CI]: 16.4-275.7), limited oral antibiotic options (aOR 5.9; 95% CI: 2.8-12.3), and genitourinary abnormalities (aOR 5.4; 95% CI: 1.8-15.9). UTI relapse occurred in 1 of the 54 (1.9%) children treated with long parenteral therapy and in 6 of the 428 (1.5%) children treated with short/no parenteral therapy (P = .57). Of the 105 children treated exclusively with discordant antibiotics, 3 (2.9%, 95% CI: 0.6%-8.1%) experienced UTI relapse. CONCLUSIONS: Long parenteral therapy was associated with age <2 months, limited oral antibiotic options, and genitourinary abnormalities. UTI relapse was rare and not associated with duration of parenteral therapy. For UTIs with limited oral options, further research is needed on the effectiveness of continued discordant therapy.

Clinical Response to Discordant Therapy in Third-Generation Cephalosporin-Resistant UTIs.

OBJECTIVES: To describe the initial clinical response and care escalation needs for children with urinary tract infections (UTIs) resistant to third-generation cephalosporins while on discordant antibiotics. METHODS: We performed a retrospective study of children <18 years old presenting to an acute care setting of 5 children's hospitals and a large managed care organization from 2012 to 2017 with third-generation cephalosporin-resistant UTIs (defined as the growth of ≥50 000 colony-forming units per mL of Escherichia coli or Klebsiella spp. nonsusceptible to ceftriaxone with a positive urinalysis). We included children started on discordant antibiotics who had follow-up when culture susceptibilities resulted. Outcomes were escalation of care (emergency department visit, hospital admission, or ICU transfer while on discordant therapy) and clinical response at follow-up (classified as improved or not improved). RESULTS: Of the 316 children included, 78% were girls and the median age was 2.4 years (interquartile range 0.6-6.5). Children were evaluated in the emergency department (56%) or clinic (43%), and 90% were started on a cephalosporin. A total of 7 of 316 children (2.2%; 95% confidence interval 0.8%-4.5%) experienced escalation of care. For the 230 children (73%) with clinical response recorded, 192 of 230 (83.5%; 95% confidence interval 78.0%-88.0%) experienced clinical improvement. In children with repeat urine testing while on discordant therapy, pyuria improved or resolved in 16 of 19 (84%) and urine cultures sterilized in 11 of 17 (65%). CONCLUSIONS: Most children with third-generation cephalosporin-resistant UTIs started on discordant antibiotics experienced initial clinical improvement, and few required escalation of care. Our findings suggest that narrow-spectrum empiric therapy is appropriate while awaiting final urine culture results.