What are the main causes of pneumatocele?

Condition analysis:
A pneumatocele results when a lung laceration, a cut or tear in the lung tissue, fills with air. A rupture of a small airway creates the air-filled cavity. Pulmonary lacerations that fill with blood are called pulmonary hematomas. In some cases, both Pneumatocele and hematomas exist in the same injured lung. A pneumatocele can become enlarged, for example when the patient is mechanically ventilated or has acute respiratory distress syndrome, in which case it may not go away for months.

Instructions:
Age: Infants younger than 1 year account for three fourths of the cases of staphylococcal pneumonia. Because pneumatoceles commonly develop as a complication of staphylococcal pneumonia, pneumatoceles are found more frequently in infants and young children. One study reported that 70% of pneumatoceles occurred in children younger than 3 years.