atelectasis

Introduction

Collapse of a lung or lung segment occurs secondary to resorption of air behind an obstructed bronchus.

Etiology

• aspirated foreign body
• inspissated mucus
  • generally postoperative
  • mechanical ventilation
• endobronchial tumor, usually bronchogenic carcinoma
• compression of the bronchus by enlarged hilar lymph nodes
• hemicolectomy (case report)

Clinical manifestations

• inspiratory chest expansion lag on affected side
• decreased fremitus
• dullness or flatness to percussion
• breath sounds may be absent over affected region
• persistent lower lobe crackles
• low-grade fever

Radiology

• trachea & heart may be shifted towards affected side
• opacification behind the heart obscuring the hemidiaphragm
• displacement of the mediastinum
• on the lateral image, an anterior triangular opacity represents atelectasis of the right middle lobe*

* right middle lobe atelectasis occurs more frequently than it does in other lobes

Management

• correct underlying disorder
• chest physiotherapy
• incentive spirometry
• ambulation (early mobilization after surgery)
• non-invasive positive pressure ventilation
  • BiPAP for atelectasis from hypoventilation due chest wall restriction (kyphosis, scoliosis, ankylosing spondylitis)
• PEEP if mechanical ventilation with endotracheal tube

More general terms

• lung disease
• sign/symptom