right middle lobe syndrome
Right middle lobe syndrome refers to chronic right middle lobe collapse, without an obstructing lesion. It is usually with associated bronchiectasis.
Epidemiology
Right middle lobe syndrome is usually encountered in older adults, with a predilection for women (see Lady Windermere syndrome). It is also seen in children .
Clinical presentation
In most cases, patients are asymptomatic. Otherwise, a chronic cough is the most common symptom. Hemoptysis, chest pain, and dyspnea are also reported .
Pathology
The underlying etiology of right middle lobe syndrome remains poorly understood, but poor collateral ventilation, a relatively narrow ostium, and infection/inflammation are all thought to play a role . The histological process identified in such cases include :
- chronic bronchitis or bronchiolitis
- bronchiectasis
- lymphoid hyperplasia
- granulomatous inflammation
- Mycobacterium avium complex infection (classic but found only in a minority of cases)
- organizing pneumonia
Radiographic features
The radiographic features of right middle lobe syndrome are a combination of:
Importantly, an obstructing bronchial lesion is usually not found.