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Bronchiolitis in tropical south India
T Cherian1, E A Simoes, M C Steinhoff
1Department of Virology, Christian Medical College and Hospital, Vellore, Tamilnadu, India.
Insights
Acute bronchiolitis in children under five is a viral illness, primarily caused by respiratory syncytial virus. Antibiotic use should be guided by radiographic evidence, especially in infants with severe lower respiratory infections.
Area of Science:
- Pediatrics
- Infectious Diseases
- Respiratory Medicine
Background:
- Acute lower respiratory infections (ALRI) are a major cause of morbidity and mortality in children under five.
- Bronchiolitis is a common cause of ALRI, particularly in infants.
- Understanding the etiology and clinical presentation of bronchiolitis is crucial for appropriate management.
Purpose of the Study:
- To investigate the clinical characteristics, viral etiology, and outcomes of acute bronchiolitis in children under five.
- To determine the role of bacterial infections and the need for antibiotic treatment in bronchiolitis.
- To assess the association between bronchiolitis and pneumonia in this population.
Main Methods:
- Prospective hospital-based study of 328 children under five with ALRI.
- Diagnosis of bronchiolitis based on clinical criteria.
- Viral detection using culture or immunofluorescence antigen detection.
- Radiographic assessment for pneumonia.
- Bacterial blood cultures performed in a subset of patients.
Main Results:
- 114 children (35%) were diagnosed with acute bronchiolitis, predominantly infants under one year.
- Severe signs like tachypnea and subcostal retractions were highly prevalent (95% and 93%).
- Viruses were identified in 71% of cases, with respiratory syncytial virus (RSV) being the most common (57%).
- Pneumonia was present in 34% of children with available radiographs; no clinical signs differentiated pneumonia.
- Bacterial pathogens were not isolated, except for Staphylococcus aureus in one fatal case.
- Mortality rate was 7%, with all deaths occurring in infants, often with concurrent pneumonia.
Conclusions:
- Bronchiolitis is a predominantly viral syndrome in this tropical region, similar to temperate climates.
- Antibiotic therapy is generally not indicated for bronchiolitis unless bacterial pneumonia is confirmed.
- Radiographic investigation is important for diagnosing pneumonia in children with lower respiratory infections, guiding antibiotic management decisions.
Abstract:
In a prospective hospital-based study of 328 children under 5 years of age with acute lower respiratory infections, 114 (35%) were diagnosed to have acute bronchiolitis. Of them, 87 (76%) were less than 1 year and 107 (94%) were less than 2 years of age. Signs of severe lower respiratory infections, namely tachypnea (respiratory rate greater than 50/min) and subcostal retraction, were present in 95% and 93%, respectively. Of 88 children of whom roentgenographs were taken, 30 (34%) had evidence of pneumonia. No clinical signs discriminated between those with and without pneumonia. By culture or immunofluorescence antigen detection, viruses were found in 81 (71%) children with bronchiolitis; respiratory syncytial virus was the most common agent, found in 65 (57%). Parainfluenza viruses were the next most common, found in 12 (11%). Most cases of bronchiolitis occurred in outbreaks during the rainy months of August through November, coinciding with respiratory syncytial virus outbreaks. Although bacterial culture of blood was done in 56 children, no respiratory pathogen was isolated. In one child with bronchiolitis and consolidation, postmortem lung aspirate yielded Staphylococcus aureus. Thus, bronchiolitis is primarily a viral syndrome in this tropical region, just as it is in temperate regions. Eight (7%) children died (all were infants); 5 had roentgenographic pneumonia and the remaining had other abnormalities contributing to death; all had been treated with antibiotics. Since one third of lower respiratory infections are bronchiolitis, and among infants under 1 year of age bronchiolitis comprises 47% of all lower respiratory infection cases, criteria for antibiotic management must take into account the availability of roentgenographic investigation.