Congenital lobar emphysema is pathologic overdistension  of a lobe. There is no true emphysema pathologically that's why many call this abnormality " Congenital lobar overinflation".

In half of the cases, there is no demonstrable cause.

On radiography or CT, there is lobar hyperlucency, attenuated vascularity, mediastinal shift and may be compression of the contralateral lung.

Treatment is by surgical lobectomy. If symptoms are mild, one might consider conservative management.

All should undergo CT scan to exclude extrinsic bronchial compression.

In the appropriate age group, you might consider bronchoscopy to exclude foreign body as a cause of overinflation. Left upper lobe foreign body aspiration is uncommon.