- Bronchiolitis is an acute viral infection of the lower respiratory tract of infants that shows a definite seasonal pattern (peaks during the winter months and persists through early spring). The disease most commonly affects infants during the first year of life.
- Respiratory syncytial virus is the most common cause of bronchiolitis, accounting for 45% to 60% of all cases. Parainfluenza viruses are the second most common cause. Bacteria serve as secondary pathogens in only a small minority of cases.
*** Clinical Presentation:
- The most common clinical signs of bronchiolitis are cough and coryza following a prodrome that suggests upper respiratory tract infection. As symptoms progress, infants may experience vomiting, diarrhea, noisy breathing, and an increase in respiratory rate.
- For those infants presenting to a hospital, examination reveals a rapid pulse and a respiratory rate. Chest auscultation reveals wheezing and inspiratory rales.
- As a result of limited oral intake due to coughing combined with fever,vomiting, and diarrhea, infants are frequently dehydrated.
- The diagnosis of bronchiolitis is based primarily on history and clinical findings. The isolation of a viral pathogen in the respiratory secretions of a wheezing child establishes a presumptive diagnosis of infectious bronchioloitis.
- The peripheral WBC count is usually normal or only slightly elevated.
- Hypoxemia is common and acts to increase the respiratory drive, whereas hypercarbia is seen only in the most severe cases.
*** Treatment:
- Bronchiolitis is a self-limiting illness and usually requires no therapy (other than reassurance and antipyretics) unless the infant is hypoxic or dehydrated.
- In severely affected children, the mainstays of therapy for bronchiolitis are oxygen therapy and intravenous fluids.
- Aerosolized (B-adrenergic therapy appears to offer little benefit for the majority of patients but may be useful in the child with a predisposition toward bronchospasm.
- Because bacteria do not represent primary pathogens in the etiology of bronchiolitis, antibiotics should not be routinely administered. However, many clinicians frequently administer antibiotics initially while awaiting culture results because the clinical and radiographic findings in bronchi-oitis are often suggestive of a possible bacterial pneumonia.
- Ribavirin may be considered for bronchiolitis caused by respiratory syncytial virus in a subset of patients (those with underlying pulmonary or cardiac disease or with severe acute infection). Use of the drug requires special equipment (small-particle aerosol generator) and specifically. trained personnel for administration via oxygen hood or misttent.
Fri Jun 08, 2007 10:20 am