Respiratory syncytial virus infection in infants and young children.

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infections in infants and young children. Epidemics occur yearly from December to March or April, leading to 100,000 hospitalizations in the United States at an estimated cost of $300 million. Physical examination findings may include clear coryza, evidence of respiratory distress, wheezing, and dehydration. Complications include apnea. Mortality runs as high as 0.5% to 1.5% in hospitalized patients. Diagnosis is based on clinical presentation, seasonal pattern, and microbiologic testing. Therapy remains largely supportive. The preponderance of evidence argues for the use of bronchodilators, especially epinephrine or albuterol, in the treatment of acute bronchiolitis. Steroids do not seem to confer any advantage. Ribavirin is expensive and should be used very selectively in infants at high risk for serious RSV disease. These infants may benefit from prophylaxis with RSV immune globulin.