Risk of Serious Bacterial Infection in ALTEs

Abstract

Source: Mittal M, Shofer F, Baren J. Serious bacterial infection in infants who have experienced an apparent life-threatening event. Ann Emerg Med. 2009; 54:(4) 523– 527; doi: 10.1016/j.annemergmed.2008.12.037To determine the incidence of serious bacterial infection (SBI) among infants who experience an apparent life-threatening event (ALTE), investigators at the Children’s Hospital of Philadelphia performed a prospective observational study. Between June 2006 and May 2007, infants younger than 12 months presenting to the emergency department (ED) with a history of ALTE were prospectively enrolled. The National Institutes of Health consensus statement was used to define ALTE,1 characterized by some combination of apnea, color change, choking, gagging, or marked change in muscle tone. Infants with a clear alternative medical diagnosis at the time of presentation (eg, febrile seizure or bronchiolitis) were excluded.A standardized interview of parents or guardians of enrolled infants was conducted and the physical examination performed by the ED physician was recorded. Medical records were reviewed to establish the hospital course and final diagnosis. The primary outcome of SBI was defined as detection of a bacterial pathogen in blood, urine, or cerebrospinal fluid. Parents or guardians of all enrolled infants were surveyed by telephone four weeks after the ED visit to detect missed cases of SBI.During the study period, 228 infants met the study definition for ALTE. Parents or guardians of 12 infants refused consent and 18 infants were missed. The median age of enrolled infants was 49.5 days and 34% were born prematurely. The rate of hospital admission was 76%. While only 4.5% of infants experienced fever during the ED visit, 22% underwent some component of an evaluation for SBI (19% had a blood culture, 18% had a urine culture, and 9% had a cerebrospinal fluid culture). There were no true positive culture results. Of the 154 infants who did not undergo any component of SBI evaluation, none were found to have an SBI during the four-week follow-up interview. Only 1 of the 198 families was unable to be reached for telephone follow-up. This infant was 3 days old with hyperbilirubinemia at the time of ED evaluation and had negative blood and urine cultures. Two other infants with ALTE were diagnosed with enteroviral meningitis (8-week-old premature twins) and did undergo a full evaluation for SBI which was negative. Approximately 9% of infants in the cohort were found to have evidence of a viral infection.The authors report that the incidence of SBI among infants presenting to the ED with a history of ALTE is very low (95% CI, 0%–1.8%). Therefore, the investigators conclude that routine full evaluation for SBI in well-appearing infants is unnecessary.ALTEs occur at an estimated frequency of 2.46 per 1,000 live births2 and are a common cause of ED visits in young infants. The diagnostic evaluation and management of infants presenting with a history of ALTE varies widely.3 (For information about risk factors for extreme events in infants hospitalized for ALTE, see AAP Grand Rounds, June 2009;21:66.4)While participating pediatric emergency medicine physicians ordered testing for SBI less frequently than previously reported,5 the study’s conclusions are strengthened by the excellent rate of follow-up. The authors acknowledge that although no infant in the study was found to have a urinary tract infection (UTI), rates of UTI among infants with ALTE range from 0% to 8% in the existing literature.6–8Even though this study was performed at a single institution, both its large size and prospective methodology provide practitioners with further evidence that most infants with ALTE need not undergo invasive testing for bacterial illness with blood and cerebrospinal fluid cultures. Physicians should continue to evaluate infants experiencing ALTE who appear ill or have other signs of infection for SBI as clinically warranted.