Congenital segmental dilatation of the colon in a newborn: a radiologic perspective of an unusual entity.

A newborn with congenital segmental dilatation of the intestine affecting the colon is presented. This rare condition, unrelated to Hirschsprung's disease, may affect any portion of the bowel and is characterized by focal dilatation of a segment of bowel flanked by normal proximal and distal bowel. While reported in the surgical literature, congenital segmental dilatation of the intestine has not been reported in the pediatric radiology literature even though pediatric radiologists may be the first to encounter imaging suggesting the diagnosis. We therefore present the characteristic imaging findings, including abdominal radiographs and images from a contrast enema, and discuss the clinical presentation, pathology findings, associations, treatment, and prognosis of congenital segmental dilatation of the intestine to increase awareness of this unusual diagnosis.

Magnetic resonance imaging following the demonstration of a normal common bile duct on ultrasound in children with suspected choledocholithiasis: what is the benefit?

BACKGROUND: The role of MRI in evaluating children with an in situ gallbladder and suspected choledocholithiasis following a negative or inconclusive US is unclear. OBJECTIVE: To determine whether MRI benefits children with suspected choledocholithiasis and a normal common bile duct (CBD) without stones on US. MATERIALS AND METHODS: We conducted a retrospective 10-year review of paired US and MRI (within 10 days) in children 18 years or younger with suspected choledocholithiasis. With MRI as a reference standard, two reviewers independently evaluated the images for CBD diameter, choledocholithiasis, cholelithiasis and pancreatic edema. Serum lipase was recorded. We calculated exact binomial confidence limits for test positive predictive values (PPVs) and negative predictive values (NPVs) using R library epiR. RESULTS: Of 87 patients (46 female, 41 male; mean age 14 years, standard deviation [SD] 4.6 years; mean interval between US and MRI 1.6 days, SD 1.8 days), 55% (48/87) had true-negative US, without CBD dilation/stones confirmed on MRI; 5% (4/87) had false-positive US showing CBD dilatation without stones, not confirmed on MRI; 33% (29/87) had true-positive US, with MRI confirming CBD dilatation; and 7% (6/87) had false-negative US, where MRI revealed CBD stones without dilatation (2 patients) and CBD dilatation with or without stones (4 patients). Patients with false-negative US had persistent or worsening symptoms, pancreatitis or SCD. The overall US false-negative rate was 17% (6/35). Normal-caliber CBD on US without stones had an NPV of 89% (48/54, 95% confidence interval: 0.77-0.96). CONCLUSION: MRI adds little information in children with a sonographically normal CBD except in the setting of pancreatitis or worsening clinical symptoms. Further evaluation is warranted in children with elevated risk of stone disease.

ACR Appropriateness Criteria® Osteomyelitis or Septic Arthritis-Child (Excluding Axial Skeleton).

Imaging plays an integral role in the evaluation of suspected musculoskeletal infections in children, not only in the accurate identification of infection such as osteomyelitis or septic arthritis, but also in guiding management. Various diagnostic modalities serve different purposes in the assessment of suspected pediatric musculoskeletal infections. The purpose of this document is to provide imaging guidance in the most frequently encountered clinical scenarios in which osteomyelitis and/or septic arthritis are suspected, outside of the axial skeleton. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion.

ACR Appropriateness Criteria® Crohn Disease-Child.

Crohn disease is an inflammatory condition of the gastrointestinal tract with episodes of exacerbation and remission occurring in children, adolescents, and adults. Crohn disease diagnosis and treatment depend upon a combination of clinical, laboratory, endoscopic, histological, and imaging findings. Appropriate use of imaging provides critical information in the settings of diagnosis, assessment of acute symptoms, disease surveillance, and therapy monitoring. Four variants are discussed. The first variant discusses the initial imaging for suspected Crohn disease before established diagnosis. The second variant pertains to appropriateness of imaging modalities during suspected acute exacerbation. The third variant is a substantial discussion of recommendations related to disease surveillance and monitoring of Crohn disease. Finally, panel recommendations and discussion of perianal fistulizing disease imaging completes the document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Imaging findings in acute pediatric coronavirus disease 2019 (COVID-19) pneumonia and multisystem inflammatory syndrome in children (MIS-C).

The two primary manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children are acute coronavirus disease 2019 (COVID-19) pneumonia and multisystem inflammatory syndrome (MIS-C). While most pediatric cases of acute COVID-19 disease are mild or asymptomatic, some children are at risk for developing severe pneumonia. In MIS-C, children present a few weeks after SARS-CoV-2 exposure with a febrile illness that can rapidly progress to shock and multiorgan dysfunction. In both diseases, the clinical and laboratory findings can be nonspecific and present a diagnostic challenge. Thoracic imaging is commonly obtained to assist with initial workup, assessment of disease progression, and guidance of therapy. This paper reviews the radiologic findings of acute COVID-19 pneumonia and MIS-C, highlights the key distinctions between the entities, and summarizes our understanding of the role of imaging in managing SARS-CoV-2-related illness in children.

A comparison of pulmonary embolism in pediatric and adult patients with acute COVID-19.

BACKGROUND: COVID-19 is associated with pulmonary embolism (PE) in adults. However, the rate of PE in pediatric patients with acute COVID-19 evaluated by CT pulmonary angiography (CTPA) has not been evaluated. OBJECTIVE: Determine PE rate in pediatric patients with acute COVID-19 and compare to adults. MATERIALS AND METHODS: A retrospective review of CTPA studies, performed between March 2020 and January 2021 on pediatric patients with acute COVID-19, but not MIS-C, was performed. CTPAs performed on an adult cohort of acute COVID-19 patients during April 2020 were reviewed for comparison. Pediatric and chest radiologists independently reviewed CTPAs of pediatric and adult patients, respectively. RESULTS: Of the 355 acute COVID-19 pediatric patients treated during the study period, 14 (16.6 ± 4.8y, median-18.5y, 64% female) underwent CTPA. Of the 1868 acute COVID-19 adults treated during two weeks in April 2020, 50 (57.2 ± 17.0y, median-57.0y, 42% female) underwent CTPA. The PE rate was 14% in the pediatric group (2 patients) and 18% in the adult group (9 patients) (p = 1.0). Both pediatric patients with PE were obese, over 18y, and had asthma, diabetes mellitus, or hypertension. No child<18y with acute COVID-19 had PE. In the adult cohort, higher alanine-aminotransferase and D-dimer levels were associated with PE (p = 0.04 and p = 0.004, respectively). CONCLUSION: Despite similar PE rates in pediatric and adult patients, PE occurred in acute COVID-19 pediatric patients who were >18y, obese, and had at least 1 comorbidity. Children <18y with COVID-19 did not have PE.

Relationship of Vitamin D Deficiency and Fatty Liver in Children as Defined by Multiple Imaging and Histologic Endpoints.

OBJECTIVES: The relationship between vitamin D deficiency (VDD) and pediatric nonalcoholic fatty liver disease (NAFLD) remains uncertain due to conflicting results and few studies with histologic endpoints. We therefore used multiple imaging and histologic NAFLD endpoints to more comprehensively assess the association between VDD and NAFLD in a large pediatric population. METHODS: Data were obtained from an ongoing pediatric NAFLD study in Bronx, NY. Briefly, overweight and obese children aged 2-18 years with alanine aminotransferase (ALT) levels ≥ 35 U/L were serially enrolled. Liver biopsy was obtained in accordance with clinical guidelines. All participants had liver imaging, namely, controlled attenuation parameter (CAP; Echosens, France) to assess steatosis and, to assess fibrosis, vibration controlled transient elastography (VCTE; FibroScan™, Echosens, France) and acoustic radiation force impulse (ARFI; Philips, Netherlands) imaging. Levels of 25-hydroxyvitamin D were measured serologically. RESULTS: N=276 (88%) of 315 participants had 25-OH vitamin D results, of whom 241 (87%) were Hispanic, 199 (72%) were male, and 92 (33%) underwent liver biopsy. VDD was univariately associated with high waist circumference (p=0.004), high-density lipoprotein level (p=0.01), season (p=0.009), and CAP score (p=0.01). In multivariate analysis, only waist circumference (p=0.0002) and biopsy inflammation grade (p=0.03) were associated with VDD, though the latter had not approximated statistical significance in univariate analysis (p=0.56). There was no association between VDD and hepatic steatosis, ballooning, NAFLD Activity Score, ARFI or VCTE elasticity scores. CONCLUSIONS: VDD was not associated with NAFLD defined by imaging and histologic endpoints, except for a possible relation with histologic inflammation grade.

Bladder prolapse through a patent urachus presenting as an umbilical mass in the newborn: characteristic prenatal sonographic findings and the diagnostic benefit of postnatal cystography.

Bladder prolapse through a patent urachus is rare. We present a newborn with an unusual exophytic, erythematous umbilical mass. Voiding cystography readily demonstrated continuity of the bladder dome with the umbilical mass, confirming bladder prolapse through a patent urachus. The diagnosis of bladder prolapse was rapidly made in a second newborn with similar imaging and clinical findings and confirmed by cystography. We discuss the embryology of this condition including the association with a vesico-allantoic cyst in utero. Pre- and postnatal images are presented. The use of cystography in diagnosis is emphasized.

Delayed sternal ossification in congenital heart disease: incidence using computed tomography.

BACKGROUND: While congenital heart disease (CHD) is known to be associated with sternal abnormalities, its association with absent sternal ossification is less well known. The literature is sparse and based on radiographs. OBJECTIVE: To quantify delayed sternal ossification in CHD using computed tomography (CT). MATERIALS AND METHODS: An imaging database search identified children with complex CHD and controls younger than 3 years of age who underwent chest CT from 2010 to 2019. Records were reviewed for demographics, CHD type and other pertinent history. Images were reviewed for manubrial or sternal segment ossification. Controls consisted of children undergoing chest CT for noncardiac reasons. Statistical analyses were conducted using a significance threshold of 0.05. RESULTS: Fifty-nine children had complex CHD (mean age: 9.4 months); 36 (61.0%) had cyanotic CHD. There were 189 controls (mean age: 17.9 months). Delayed sternal ossification was present in 7 children (11.9%) in the study group; 6 had cyanotic heart disease (85.7%). Patterns of ossification included manubrium only; manubrium and first sternal segment; first and second sternal segments; and manubrium, first segment and hypoplastic second segment. Three controls (1.6%) had sternal ossification delay, all with manubrial ossification only. Delayed sternal ossification was more prevalent in the study group than in the controls (P=0.002). Compared to the controls, a higher incidence of delayed sternal ossification was seen in children with cyanotic CHD (P<0.001) but not acyanotic CHD (P=0.37). CONCLUSION: Delayed sternal ossification occurs in children with CHD, particularly cyanotic forms, and requires no additional work-up.

Feasibility study of a novel portable digital radiography system modified for fluoroscopy in the neonatal intensive care unit.

BACKGROUND: A portable radiographic system capable of fluoroscopic imaging in the neonatal intensive care unit (NICU) potentially benefits critically ill neonates by eliminating the need to transport them to a fluoroscopy suite. OBJECTIVE: To evaluate whether a portable bedside fluoroscopy system in the NICU can deliver comparable image quality at a similar dose rate to a standard system in a fluoroscopy suite. MATERIALS AND METHODS: In phase A, 20 patients <3 years of age and scheduled to undergo upper gastrointestinal series (upper GI) or voiding cystourethrograms (VCUG) in the radiology fluoroscopy suite were recruited to evaluate a portable fluoroscopic unit. A modified portable radiographic system with a cassette-sized detector and an in-room fluoroscopy system were sequentially used in the same examination. Four radiologists compared the image quality of 20 images from each system using the Radlex score (1-4) for five image quality attributes. The radiation dose rates for the portable and in-suite systems were collected. In phase B, fluoroscopy studies were performed in 5 neonates in the NICU and compared to the 20 previous neonatal studies performed in the department. Clinical workflow, examination time, fluoroscopy time, scattered radiation dose and patient radiation dose were evaluated. RESULTS: In phase A, average dose rates for in-room and portable systems were equivalent, (0.322 mGy/min and 0.320 mGy/min, respectively). Reader-averaged Radlex scores for in-room and portable systems were statistically significantly greater (P<0.05) for all attributes on the portable system except for image contrast. In phase B, scattered radiation from the average fluoroscopy time (26 s) was equivalent to the scattered radiation of 2.6 portable neonatal chest radiographs. Procedure time and diagnostic quality were deemed equivalent. The average dose rate in the NICU with the portable system was 0.21 mGy/min compared to 0.29 mGy/min for the in-room system. CONCLUSION: The portable fluoroscopy unit is capable of providing comparable image quality at equivalent dose levels to an in-room system for neonates with minimal risks to the staff and other patients in the NICU.

Is necrotizing enterocolitis the same disease in term and preterm infants?

INTRODUCTION: Necrotizing enterocolitis predominantly affects preterm (PT) infants. The paucity of data regarding the clinical course in term infants makes it difficult to predict outcomes and counsel families. To identify predisposing factors and gain a better understanding of the clinical course of NEC in term infants, we reviewed our experience with term infants and compared it to outcomes in PT infants. METHODS: We performed a 10 year retrospective review of all infants admitted to our NICU with Bell stage 2 NEC or greater. Infants < 37 weeks gestation were considered PT. Term and PT infant comorbidities, outcomes and intraoperative findings were compared. RESULTS: Fifteen (12%) of 125 infants were term. Compared to PT infants, term infants were more likely to have congenital heart disease (33% term vs. 10% PT, p = 0.02) and develop NEC sooner (4 days in term vs. 17 days in PT, p < 0.001) but were less likely to require operative intervention (20% term vs. 38% PT; p = 0.17). There was no significant difference in Bell stage, survival and development of intestinal failure. NEC totalis occurred exclusively in PT infants. CONCLUSIONS: NEC in term infants has unique clinical features that distinguishes it from NEC in PT infants.

Imaging Findings in Multisystem Inflammatory Syndrome in Children (MIS-C) Associated With Coronavirus Disease (COVID-19).

BACKGROUND. A multisystem inflammatory syndrome in children (MIS-C) associated with coronavirus disease (COVID-19) has recently been described. OBJECTIVE. The purpose of our study was to evaluate the imaging findings of MIS-C associated with COVID-19. METHODS. Imaging studies and medical records of patients (age range, 0-20 years) admitted with MIS-C between April 22 and May 21, 2020, were retrospectively reviewed. Thoracic imaging studies were evaluated for parenchymal, mediastinal and hilar, and cardiovascular abnormalities. Abdominal imaging studies were evaluated for abnormalities of solid viscera, hollow viscera, and the peritoneum as well as the mesentery and retroperitoneum. Studies were reviewed independently by two radiologists, and disagreements were resolved by a third senior radiologist. RESULTS. Sixteen patients (10 male and six female patients; age range, 20 months-20 years) were included in this study. All 16 patients presented with fever. Other presenting signs and symptoms included the following: vomiting (12/16, 75%), abdominal pain (11/16, 69%), rash (10/16, 63%), conjunctivitis (8/16, 50%), diarrhea (7/16, 44%), headache (6/16, 38%), and sore throat (5/16, 31%). Shortness of breath and cough were each present in one patient. Chest radiography showed cardiomegaly (10/16, 63%), congestive heart failure or cardiogenic pulmonary edema (9/16, 56%), atelectasis (9/16, 56%), pleural effusions (7/16, 44%), acute respiratory distress syndrome (2/16, 13%), and pneumonia (1/16, 6%). Eight patients (50%) were evaluated for pulmonary embolism (PE) (six [75%] by CT angiography [CTA] and two [25%] by ventilation-perfusion scintigraphy). In two of the eight patients (25%), CTA showed a segmental PE. Abdominal imaging findings (ultrasound, CT, and radiography) included small-volume ascites (6/16, 38%), hepatomegaly (6/16, 38%), echogenic kidneys (5/16, 31%), bowel wall thickening (3/16, 19%), gallbladder wall thickening (3/16, 19%), mesenteric lymphadenopathy (2/16, 13%), splenomegaly (1/16, 6%), and bladder wall thickening (1/16, 6%). The frequencies of findings based on all the reviewed modalities were as follows: cardiomegaly (12/16, 75%), pleural effusion (10/16, 63%), and atelectasis (10/16, 63%). Absolute interobserver agreement was 0.69-1 for thoracic findings and 0.17-1 for abdominal findings. Fifteen patients (94%) were discharged from the hospital (length of hospital stay: range, 3-20 days), and one patient remained in the hospital at the end of the study period. There were no mortalities. CONCLUSION. MIS-C associated with COVID-19 is characterized predominantly by cardiovascular abnormalities, although solid visceral organ, gallbladder, and bowel abnormalities as well as ascites are also seen, reflecting a multisystemic inflammatory process. CLINICAL IMPACT. The constellation of imaging findings in the setting of COVID-19 may alert radiologists to the diagnosis of MIS-C before rapid deterioration of patients.

ACR Appropriateness Criteria® Vomiting in Infants.

Vomiting in infants under the age of 3 months is one of the most common reasons for parents to seek care from their doctor or present to an emergency room. The imaging workup that ensues is dependent on several factors: age at onset, days versus weeks after birth, quality of emesis, bilious or nonbilious vomiting, and the initial findings on plain radiograph, suspected proximal versus distal bowel obstruction. The purpose of these guidelines is to inform the clinician, based on current evidence, what is the next highest yield and most appropriate imaging study to pursue a diagnosis. The goal is rapid and accurate arrival at a plan for treatment, whether surgical or nonsurgical. The following modalities are discussed for each variant of the symptom: plain radiography, fluoroscopic upper gastrointestinal series, fluoroscopic contrast enema, ultrasound of the abdomen, nuclear medicine gastroesophageal reflux scan. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

COVID-19 in pediatric patients: a case series from the Bronx, NY.

BACKGROUND: Coronavirus disease 2019 (COVID-19) primarily affects adults, with a lower incidence in children. OBJECTIVE: To report our experience with critically ill children with COVID-19. MATERIALS AND METHODS: We reviewed the medical records of children with COVID-19 who were admitted Feb. 25 to May 1, 2020. We reviewed patient demographics, symptoms, comorbidities, requirement for respiratory support, evidence of acute myocardial injury, and chest radiographs. RESULTS: The study included 19 children and adolescents (ages 2 months to 18 years, median 8 years; 10 males, 9 females; 18 COVID-19-positive, 1 COVID-19-negative with positive exposure). Presenting symptoms included fever (89%), cough (68%), respiratory distress (68%) and vomiting/diarrhea (47%). Comorbidities were present in 12 (63%). Fourteen required intensive care; eight required intubation. Two children died. Five patients developed acute myocarditis (median age 7 years); in all five, chest radiographs were notable for cardiomegaly and pulmonary congestion or interstitial edema. Of these five, one (age 18 years), who had underlying hypertension and obesity, developed multifocal pneumonia and renal failure. The other four were previously healthy; three (ages 5 years, 7 years, 8 years) were subsequently diagnosed with multisystemic inflammatory syndrome in children (MIS-C); one developed pulmonary opacities consistent with adult respiratory distress syndrome, three (60%) had no parenchymal pulmonary opacities. Fourteen patients (median 13 years), most with comorbidities, had no acute myocardial injury. Chest radiographs in 13 (93%) demonstrated parenchymal lung disease with a predominant perihilar and basilar distribution. CONCLUSION: Myocarditis without pulmonary disease occurred in children in their first decade as a component of MIS-C, a newly described syndrome of multisystemic inflammation requiring further investigation. Pulmonary disease dominated the radiographic features of COVID-19-positive adolescents in their second decade in whom radiographs demonstrated predominantly perihilar and basilar distribution of lung opacities.

Cytotoxic lesion of the splenium of the corpus callosum in a patient with EVALI.

Since first recognized in July 2019, numerous cases of a lung illness associated with electronic-cigarette use or vaping particularly tetrahydrocannabinol in adolescents and adults have been reported. As of January 2020, the Center for Disease Control has reported over 2500 cases of electronic-cigarette or vaping product use-associated lung injury (EVALI), including 60 deaths. Affected patients most commonly present with respiratory or gastrointestinal complaints although neurological symptoms including headache, confusion and lethargy have been reported. We present a new as yet unpublished finding in the brain of a previously healthy teenage boy with EVALI. Brain imaging may be warranted in this patient population.

Vaping associated lung injury: A potentially life-threatening epidemic in US youth.

BACKGROUND: The Center for Disease Control (CDC) has identified a national outbreak in the United States of over 2600 cases of e-cigarette or vaping product use-associated lung injury (EVALI), including 60 deaths as of January 2020. We describe our experience in six adolescents. MATERIAL AND METHODS: We identified all pediatric patients diagnosed with EVALI by CDC guidelines over a 6-month period at our health system. Clinical presentation, hospital course, and imaging were reviewed. RESULTS: Six patients were identified (three males, three females; median age 18.5 years). Presenting symptoms varied, including constitutional, gastrointestinal, neurologic, and respiratory complaints with pulmonary symptomatology becoming the dominant feature of the illness. Three patients required intensive care unit-level care, one of whom expired 36 days after presentation. Three had bronchoalveolar lavage, two with evidence of lipid-laden macrophages. Four had pulmonary function testing with various results. Admission chest radiographs in all revealed bibasilar interstitial infiltrate which rapidly progressed. Five patients had computed tomography chest imaging demonstrating: confluent pulmonary infiltrates with subpleural sparing (n = 2), generalized ground-glass opacities (n = 1), patchy ground-glass opacities (n = 1) and a reticulonodular pattern (n = 1). Brain magnetic resonance imaging (MRI) obtained in two patients was normal in one and showed a focal signal abnormality in the corpus callosum in one. CONCLUSION: We describe the clinical course and radiologic findings of EVALI in our adolescent patients and present a new finding in the brain not yet described in the literature. Given the diversity of presenting symptoms, a high level of suspicion for EVALI is necessary for patients reporting vaping product use regardless of the presence of pulmonary complaints. Brain MRI should be strongly considered in patients with neurologic symptoms.

Management of Intussusception in the Pediatric Emergency Department: Risk Factors for Recurrence.

BACKGROUND: The standard treatment for intussusception is air reduction enema (ARE) with inpatient observation for 24 to 48 hours to monitor for recurrence. More recent but limited observations suggest that patients who have undergone successful ARE can safely be discharged after 4 to 6 hours of observation. Our primary objective was to identify risk factors associated with early recurrence. Our secondary objectives included validating risk criteria from prior studies and identifying risk factors for ARE failures. DESIGN/METHODS: A retrospective cohort study of children discharged from a large urban quaternary hospital with a final diagnosis of intussusception (International Classification of Diseases, Ninth Revision, code 560.0) or who underwent ARE from 2005 to 2015 was identified. Demographic data, radiology images, and clinical course were recorded. Repeat visits, cases with incomplete medical records, and those with incorrect diagnoses were excluded. RESULTS: A total of 250 cases were identified. Two hundred cases were included for analysis. Fifty were excluded. Of the 163 who had successful reduction with ARE, 22 patients (13.5%) recurred, and 12 (7.3%) recurred within 48 hours. Fever (odds ratio, 4.25; P = 0.04; 95% confidence interval, 1.04-17.3) and female sex (odds ratio, 7.94; P = 0.01; 95% confidence interval, 1.82-34.6) were independently associated with early recurrence. No radiologic features were associated with early recurrence. CONCLUSIONS: Early recurrence after successful ARE was low, although more frequent in girls and in those with fever over 100.4°F. We therefore advocate for prospective studies to validate these risk criteria to identify patients who are at low risk for early recurrence and may qualify for early discharge from the emergency department.