We describe 4 nonconsecutive cases of infants admitted to Catholic University pediatric intensive care unit (PICU) because of complicated respiratory syncytial virus (RSV) infection during winter RSV outbreaks from the year 2000 to the year 2003. A hyponatremic epileptic status (as in the first case) has been reported by several authors as a rare RSV complication, potentially leading to death. The second infant developed a serious pulmonary edema after a subglottic obstruction (croup) associated with RSV infection. The remaining 2 infants developed a pneumothorax and subcutaneous emphysema while breathing spontaneously during an RSV bronchiolitis. In all infants, a full recovery and PICU discharge was achieved despite the need for mechanical ventilation in cases 1 and 2. Increased intrapleural negative pressure or its combination with hypoxia/hypercapnia has been suggested as the common factor possibly joining these different clinical pictures.