pediatrics
Bronchiolitis
Key Points
Bronchiolitis is an acute, viral, lower respiratory tract infection affecting infants<24 months and is typically caused by respiratory syncytial virus (RSV), rhinovirus, or parainfluenza virus type 3. Edema and exudate in medium and small bronchi and bronchioles cause partial obstruction and air trapping; atelectasis and/or pneumonia cause hypoxemia in more severe cases. Typical manifestations include fever, tachypnea, retractions, wheezing, and cough. Clinical evaluation is usually adequate for diagnosis, but more severely ill children should have pulse oximetry, chest x-ray, and rapid antigen testing for RSV. Indications for hospitalization include accelerating respiratory distress, ill appearance (eg, cyanosis, lethargy, fatigue), apnea by history, hypoxemia, and inadequate oral intake. Treatment is supportive; bronchodilators sometimes relieve symptoms but probably do not shorten hospitalization, and systemic corticosteroids are not indicated in previously well infants with bronchiolitis. Passive immunoprophylaxis against RSV is recommended for all infants. 