Rational approach to the wheezy infant.

The infant or child presenting to the physician's office with persistent or recurrent wheezing during the first two year's of life poses a diagnostic dilemma. A careful medical history should document risk factors for persistent wheezing, including maternal smoking, feeding practices, environmental history, and family history of asthma or cystic fibrosis (CF). A suggested diagnostic approach to the causes of infantile wheezing is outlined. A chest radiograph is non-specific, but may suggest a congenital airway anomaly. Infant pulmonary function testing (IPFT) can help differentiate between central airflow (intrathoracic, extrathoracic, or fixed) and peripheral airflow obstruction. The infant with either intrathoracic, extrathoracic, or fixed airflow obstruction on the PFT may benefit from flexible fiberoptic bronchoscopy. The infant with either an intrathoracic or fixed airway obstruction should undergo an upper gastrointestinal (UGI) series to evaluate the anatomy for extrinsic tracheal compression. The response to treatment with anti-inflammatory therapy may suggest an inflammatory disease such as asthma or CF. The infant with peripheral airflow obstruction and a good response to bronchodilators (> or =25%) using the forced exhalation technique is given the diagnosis of infantile asthma. The infant with peripheral airflow obstruction and no response to bronchodilators should be evaluated further for possible gastroesophageal reflux disease (GERD), and for other causes, which are associated with wheezing symptoms.