Frequency and prediction of abnormal findings on neuroimaging of infants with bulging anterior fontanelles

Objectives: This study sought to determine the frequency of clinically significant abnormal findings on neuroimaging using neurosonography (NS) in infants with bulging anterior fontanelles (BAFs) and to identify infants at high or low risk for clinically significant abnormal findings on neuroimaging. Methods: NS was performed in 45 consecutive infants with BAFs brought to the emergency department of a tertiary care hospital. NS reports were categorized as normal, clinically insignificant abnormal, or clinically significant abnormal. For each patient, demographic data, laboratory test results, and clinical diagnosis and outcome were obtained for analysis. Results: Eighteen febrile and 27 nonfebrile infants with BAFs were evaluated. Clinically significant abnormal findings on NS were noted in 16 of 45 patients (36%), five of whom were febrile and 11 of whom were nonfebrile. Brain edema resulting from infection was the most common finding on NS. Univariate analysis indicated that age younger than two months in febrile patients and abnormal findings on neurologic examination in nonfebrile patients were significant clinical predictors for clinically significant abnormal findings on NS in infants with BAFs. Patients presenting with either of these clinical predictors were identified as high risk for abnormal findings on NS. Of the high-risk patients, 15 of 17 patients (88%) had clinically significant abnormal findings on NS, compared with one of 28 patients (4%) in the low-risk group. Conclusions: This study shows a 36% prevalence of clinically significant abnormal findings on NS in infants with BAFs. Emergent neuroimaging should be considered for infants who meet high-risk criteria: 1) febrile children younger than two months or 2) nonfebrile children with abnormal findings on neurologic examination.