Purpose: Apparent life-threatening events (ALTE) can be associated with occult infections due to respiratory syncytial virus (RSV). Similarly, young infants with bronchiolitis can present with apnea in the absence of respiratory symptoms, especially those that are premature, less than 1 month of age and have a prior history of (h/o) apnea. The objective of this study is to describe the occurrence of apnea and RSV infections in infants presenting with an ALTE.
Methods: A retrospective analysis of a prospectively collected cohort of infants aged <2 years presenting to a large, urban tertiary care children's hospital emergency department with signs and symptoms of an ALTE between March 2001 and October 2007. Only patients with no readily identifiable reason for their event were enrolled, i.e. no fever or respiratory symptoms. Clinical and demographic information was collected at the time of enrollment. We performed descriptive statistics and univariate analysis to evaluate risk for apnea and positive RSV test with clinical predictor variables.
Results: During the study period, 662 patients presented with an ALTE. The mean age was 2.7 months (95% CI 2.4 – 3.0 months), and 491 (74%) had a history of apnea. Patients with apnea were more likely to be premature, have had a previous ALTE, receive stimulation or CPR, and require ICU admission. (see Table 1)
RSV testing was performed in 102 (15%) patients and was more likely to be performed in patients with h/o prematurity, a prodrome, choking, requiring CPR and being admitted to the ICU or requiring intubation. Ten (9.8%) patients were RSV positive; all of these patients had h/o apnea and color change. RSV positive patients were more likely to be premature infants and patients with a prodrome. There was no difference between RSV test status and need for ICU admission or intubation. (see Table 2)
Conclusion: Patients with ALTE commonly present with h/o apnea. A previous ALTE and prematurity are risk factors for patients presenting with apnea and ALTE. In patients with an ALTE, a positive RSV test is more likely to occur in premature infants, and those infants with a prodrome. RSV testing should be considered during the evaluation of patients with an ALTE.
Table 1: Risk factors associated with history of apnea and ALTE
Table 2: Risk Factors associated with RSV positive infants with ALTE