Clinical definition of respiratory viral infections in young children and potential bronchiolitis misclassification.

Viral respiratory infections are often grouped as a single respiratory syndrome named 'viral bronchiolitis', independently of the viral etiology or individual risk factors. Clinical trials and guidelines have used a more stringent definition of viral bronchiolitis, including only the first episode of wheezing in children less than 12 months of age without concomitant respiratory comorbidities. There is increasing evidence suggesting that this definition is not being followed by pediatric care providers, but it is unclear to what extent viral respiratory infections are currently misclassified as viral bronchiolitis using standard definitions. We conducted a retrospective analysis of hospitalized young children (≤3 years) due to viral respiratory infections. Bronchiolitis was defined as the first wheezing episode less than 12 months of age. Demographic variables and comorbidities were obtained by electronic medical record review. The study comprised a total of 513 hospitalizations (n=453). Viral bronchiolitis was diagnosed in 144 admissions (28.1%). Notably, we identified that the majority of children diagnosed with bronchiolitis (63%) were misclassified as they had prior episodes of wheezing. Many children with bronchiolitis misclassification had significant comorbidities, including prematurity (51%), neuromuscular conditions (9.8%), and congenital heart disease (9.8%). Misclassification of bronchiolitis is a common problem that may lead to inappropriate management of viral respiratory infections in young children. A comprehensive approach that takes into consideration viral etiology and individual risk factors may lead to a more accurate clinical assessment of this condition and would potentially prevent bronchiolitis misclassification.

[Bronchiolitis: conceptual review]. / Bronquiolitis: revisión conceptual.

Bronchiolitis is a term which brings together several processes which may confuse anyone who is not familiar with the subject. We will review these processes by focusing on the most common types.

Respiratory syncytial virus testing during bronchiolitis episodes of care in an integrated health care delivery system: a retrospective cohort study.

BACKGROUND: Bronchiolitis has the highest incidence rate of any lower respiratory infection among infants and children <2 years of age. Respiratory syncytial virus (RSV) is the most common etiology of bronchiolitis. The American Academy of Pediatrics does not recommend routine RSV testing for infants and children with bronchiolitis. The clinical predictors of RSV testing are unknown. OBJECTIVES: The aims of this study were to identify the rates and predictors of RSV testing during bronchiolitis and to explore the relationship between RSV test results and antibiotic treatment among infants and children aged <2 years. METHODS: A retrospective study was conducted of 123,264 infants ≥32 weeks' gestational age (GA) who were born at 1 of 6 Northern California Kaiser Permanente Medical Center Program hospitals between 1996 and 2004. A bronchiolitis episode of care (EOC) was defined as ≥1 medical encounters with a bronchiolitis diagnosis code followed by 14 clear days without a bronchiolitis-related medical encounter. Descriptive statistics were used to report the frequency of tests, and logistic regression was used to assess the effect of hospitalization, chronologic age, gestational age, and season on the frequency of testing for RSV. Rapid direct fluorescent antibody testing was performed during the study. RESULTS: The birth cohort was 51.2% male and 42.7% white, 20.8% Hispanic, 20.3% Asian, 8.4% African American, and 7.9% other. Of 23,748 bronchiolitis EOCs, 4969 (20.9%) had ≥1 test for RSV. Overall, 44.2% of all tests were positive for RSV. Physicians ordered RSV tests in 30.4% and 26.7% of bronchiolitis EOCs for infants born at 32 to 33 and 34 to 36 weeks' GA, respectively, compared with 17.9% of bronchiolitis EOCs for infants born at ≥41 weeks' GA. Bronchiolitis hospitalization, younger chronologic age, prematurity, and RSV season were associated with RSV testing in a multivariate model controlling for other variables, with an adjusted odds ratio (AOR) of 28.55 (95% CI, 24.99-36.62) for hospitalization status; AOR of 6.89 (95% CI, 5.19-9.15) for chronologic age <1 month; AOR of 0.85 (95% CI, 0.76-0.95) for GA >41 weeks; and AOR of 2.48 (95% CI, 2.24-2.74) for RSV season (December-March). Among hospitalized infants who were tested and had a diagnostic code suggesting treatment with antibiotics, use of antibiotics was significantly lower among those with a positive RSV test (63.4%) than those with a negative RSV test (75.5%) (χ(2) test; P < 0.001). CONCLUSIONS: Approximately 20% of these children with bronchiolitis EOCs were tested for RSV; of those tested, about half were positive. In this integrated health care system, hospitalization with bronchiolitis, chronologic age, gestational age <37 weeks, neonatal oxygen exposure, and bronchiolitis EOC during the RSV season were the factors associated with testing for RSV.

Severity of respiratory syncytial virus bronchiolitis is affected by cigarette smoke exposure and atopy.

OBJECTIVE: Respiratory syncytial virus (RSV) bronchiolitis is a common cause of hospitalizations in children and has been increasingly identified as a risk factor in the development of asthma. Little is known about what determines the severity of RSV bronchiolitis, which may be helpful in the initial assessment of these children. DESIGN: We evaluated a variety of environmental and host factors that may contribute to the severity of RSV bronchiolitis in the RSV Bronchiolitis in Early Life prospective cohort study. Severity of bronchiolitis was based on the quantization of lowest O(2) saturation and the length of stay. These factors included the child's and family's demographics, presence of household allergens (dust mite, cat, dog, and cockroach), peripheral blood eosinophil count, immunoglobulin E level, infant feeding, prior illnesses, exposure to intrauterine and postnatal cigarette smoke, and family history of atopy. PATIENTS: We prospectively enrolled 206 hospitalized infants, all under 12 months old (4.0 +/- 3.3 months old), with their first episode of severe RSV bronchiolitis (mean O(2) saturation: 91.6 +/- 7.3%; length of stay: 2.5 +/- 2.5 days; presence of radiographic opacities: 75%). Patients were excluded for a variety of reasons including previous wheezing, regular use of bronchodilator or antiinflammatory medications, any preexisting lung disease including asthma, chronic lung disease of prematurity/bronchopulmonary dysplasia, or cystic fibrosis; gastroesophageal reflux disease on medical therapy; or congenital anomalies of the chest or lung. RESULTS: Age was found to be a significant factor in the severity of infection. The younger an infant was, the more severe the infection tended to be as measured by the lowest oxygen (O(2)) saturation. We also found that infants exposed to postnatal cigarette smoke from the mother had a lower O(2) saturation than those not exposed. However, there was no significant difference in RSV bronchiolitis severity between infants exposed only to intrauterine smoke and those infants never exposed to cigarette smoke. Infants with a family history of atopy, especially a maternal history of asthma or hay fever, had a higher O(2) saturation. Although a history of maternal atopy seemed to be protective, there was no association between allergens and bronchiolitis severity, although 25% of households had elevated allergen levels. Black infants demonstrated less severe RSV bronchiolitis than their white counterparts. Multivariate analysis revealed age, race, maternal atopy, and smoking to be associated with severity of RSV bronchiolitis. CONCLUSION: The severity of RSV bronchiolitis early in life seems modified by postnatal maternal cigarette smoke exposure and atopy and age of the infant, not by levels of allergens in the home environment.

Infección viral del tracto respiratorio inferior

Las infecciones respiratorias agudas son una de las principales causas de morbilidad y mortalidad entre los niños. Con el desarrollo de tecnologías de diagnóstico rápido para la detección de antígenos virales es posible reconocer el agente viral de la infección respiratoria en horas. El diagnóstico etiológico de infección respiratoria viral es no sólo cada vez más importante para la selección apropiada de los pacientes que deben recibir tratamiento antiviral o con antibióticos, sino también para el control de la diseminación de las infecciones respiratorias virales en salas pediátricas. En la Clínica Amparo Infantil Santa Ana de Medellín ocurrió un brote de infección respiratoria aguda del tracto respiratorio inferior en el último trimestre de 1994 producida por virus. Los virus detectados fueron virus respiratorio sincitial 41.8 por ciento, adenovirus 33,3 por ciento, parainfluenza tipo 1, en el 8.3 por ciento e infección mixta en el 16.7 por ciento. Se describe el método diagnóstico utilizado en la detección de los antígenos virales y las características de este brote.