An acute life-threatening event (ALTE) is defined as any unexpected and frightening change in condition characterized by apnea, color change (usually blue or pale), sudden limpness, choking, or gagging. Of the following, the MOST likely cause is

An acute life-threatening event (ALTE) is defined as any unexpected and frightening change in condition characterized by apnea, color change (usually blue or pale), sudden limpness, choking, or gagging. Of the following, the MOST likely cause is

The primary cause of bronchiolitis is

Immunizations have had a great impact on the incidence of pneumonia caused by all the following EXCEPT

Blood cultures should be performed on hospitalized children to attempt to diagnose a bacterial cause of pneumonia. Blood cultures are positive in

Definitive diagnosis of pulmonary arterial hypertension is made by