Postnatal over-distension of one or more lobes of a histologically normal lung, as a result of a collapse of bronchi (a cartilaginous deficiency in the tracheobronchial tree; check valve obstruction with air trapping) or extrinsic pressure (anomalous pulmonary artery) on the airway or idiopathic causes.
The normal lobes are compressed and the mediastinum is shifted away from the affected side.
The upper lobes are more commonly involved (especially the left).
Males more affected than females.
In about 40% associated anomalies (heart, kidneys).
Respiratory failure with cyanosis.
Sometimes dramatic presentation due to overdistension of the affected lobe (mimics a tension pneumothorax).
Plain chest radiograph, CT scan
Ventilatory perfusion lung scannings.
Indication for operation:
Conservative therapy is useless in congenital forms. Clear indication for resection.
Urgent lobe or segment resection. Placement of a chest tube into emphysematous lobe can have catastrophic results (air leak, bleeding).
In rare cases, the cause of the bronchial obstruction can be operatively treated.
Chest tubes may be removed if the lung is fully expanded and drainage volumes decrease below 20 to 50cc during a 24 hour period.