Characteristics

• Also known as Swyer–James syndrome or unilateral lobar emphysema.

• Follows an acute viral infective bronchiolitis (e.g. adenovirus or measles) to the developing lung during childhood (< 8 years old). The children then develop a post infective form of obliterative bronchiolitis with bronchiectasis and distal airspace destruction.

• Usually affects the whole of one lung, but can affect both lungs and very occasionally has been shown to affect lobar or segmental parts of the lung.

Clinical features

• Often asymptomatic.

• Cough, SOB, wheeze.

• History of recurrent childhood infections.

• Presentation usually in adulthood.

Radiological features

• CXR – there is typically increased transradiancy throughout one lung. Reduced volume in affected lung. May be mediastinal shift towards the affected side. Air trapping in expiration. Reduced pulmonary vasculature in low attenuation areas on the affected side.

• HRCT – often bilateral mosaic pattern of reduced attenuation and air trapping demonstrated. Again reduced pulmonary vasculature in low attenuation areas. Bronchiectasis may be present.

• Partial involvement of only one lobe or lung is difficult to diagnose.

Differential diagnosis

• Hypogenetic lung syndrome (this is associated with proximal interruption of the pulmonary artery).

• Pulmonary artery hypoplasia.

• Thromboembolic disease (seen more in adults).

• Localised bullous emphysema (seen more in adults).

• Bronchial obstruction.

Management

• No active management in most patients.

• Physiotherapy and long-term antibiotic requirement may be necessary.