Atelectasis Overview and Types

Atelectasis Definition

• Atelectasis is the partial or complete collapse of a lung or a portion of it
• This collapse results from inadequate expansion of alveoli, reducing gas exchange surface area

Types of Atelectasis

Resorption Atelectasis

• Caused by an obstruction preventing air from reaching distal airways
• Air in the affected alveoli gradually absorbs, leading to collapse
• Common causes include:
  • Bronchial obstruction (e.g., mucous plugs, post-operative)
  • Foreign body aspiration (especially in children)
  • Bronchial asthma
  • Bronchiectasis
  • Chronic bronchitis
  • Intrabronchial tumors (possibly a first sign of malignancy)

Compression Atelectasis

• Caused by accumulation of fluid, blood, or air in the pleural cavity
• Common causes include:
  • Pleural effusions (e.g., congestive heart failure)
  • Pneumothorax (air in the pleural cavity)
  • Basal atelectasis (often in bedridden patients with ascites, or post-surgery due to shallow breathing)

Fluid Accumulation

• Pleural effusion (fluid build-up in pleural cavity) puts pressure on the lung, preventing expansion and causing collapse
• Causes include congestive heart failure

Air Accumulation

• Pneumothorax (air in the pleural cavity) creates pressure that collapses the lung
• Causes include injury, lung disease, or spontaneous occurrences

Blood Accumulation

• Hemothorax (blood in the pleural cavity) exerts pressure on the lung, causing collapse
• Causes include trauma or certain medical conditions

Contraction Atelectasis (Cicatrization Atelectasis)

• Occurs when lung scarring or fibrosis prevents full expansion
• Scarring can be in the lung tissue or pleura
• Leads to collapse of the affected lung area due to impaired air filling