Table 3.

Underlying causes of recurrent or chronic pneumonia in the same lobe or segment.

Right Middle Lobe Syndrome

Localized airway obstruction

Endobronchial foreign body

Localized malacia or bronchiectasis

Congenital malformation; congenital webs; complete cartilage rings

Mucus plug

Carcinoid or other pedunculated tumor; intramural airway tumor

Inflammatory pseudotumor secondary to previous intubation

Localized airway compression

Vascular ring; pulmonary artery sling

Enlarged lymphnodes

Enlarged cardiac chamber due to right-to-left shunting; cardiomyopathy

Fibrosing mediastinitis

Mediastinal cancer

Parenchimal disease

Congenital malformation

Infection in residual cystic change after a cavitating pneumonia or tuberculosis

Lung cancer