pneumothorax

Introduction

The presence of air or gas in the pleural cavity.

Etiology

• primary spontaneous pneumothorax*
  • rupture of apical bullae
  • smoking increases risk (30 fold)
  • thoracic endometriosis
  • tall stature
• secondary spontaneous pneumothorax
  • COPD (most common), emphysema
  • asthma, status asthmaticus
  • interstitial lung disease
    • lymphangioleiomyomatosis (premenopausal women)
    • Langerhans cell granuloma
    • sarcoidosis
    • idiopathic pulmonary fibrosis
  • bullous lung disease
  • cystic fibrosis
  • lung tumors, lung cancer
  • end-stage fibrosis
  • honeycombing of the lungs
  • Marfan's syndrome
  • catamenial hemopneumothorax (during menses)
  • AIDS, Pneuomocystis pneumonia
  • tuberculosis
  • connective tissue disease with pulmonary involment
    • rheumatoid pleurisy
    • lupus pleuritis
• tension pneumothorax
• iatrogenic
  • thoracentesis
  • trauma
  • esophageal rupture
  • tracheal fracture
  • subclavian needle sticks
  • high positive end-expiratory pressure with mechanical ventilation
  • transtracheal aspiration
  • severe Valsalva maneuver
  • pneumoperitoneum

* primary spontaneous pneumothorax: no underlying lung disease

Epidemiology

• primary spontaneous pneumothorax*
  • annual incidence 9/100,000
  • male:female ratio 6:1
  • up to 40% patients have a recurrence
• secondary spontaneous pneumothorax
  • annual incidence 4/100,000
  • male:female ratio 3:1

Pathology

• secondary pneumothorax
• occur in patients with compromised pulmonary function
• frequent airleaks or bronchopleural fistulas complicate resolution

Genetics

• spontaneous pneumothorax may be associated with defects in FLCN

Clinical manifestations

• sudden onset pleuritic chest pain
• dyspnea
• inspiratory chest expansion lag on affected side
• absent fremitus
• hyperresonant or tympanitic to percussion
• cough may be present
• absent breath sounds

Radiology

• chest X-ray (upright)
  • pneumothorax appears at the apex of the lung
  • end-expiratory chest X-ray is more sensitive for identifying a small pneumothorax
  • tracheal deviation
  • sensitivity: 52%; specificity 100%
• CT of lung
  • look for interstitial lung disease, alveolar infiltrates, & subpleural blebs & bullae especially in the lung contralateral to the pneumothorax
• ultrasound: sensitivity: 88%; specificity 99%
  • lung sliding indicated no pneumothorax at that speicific location
  • presence of a lung point confirms edge of pneumothorax

Complications

• tension pneumothorax

• disease interaction(s) of pneumothorax with mechancal ventilation

Management

• initial management for large, hemodynamically significant pneumothorax (primary or secondary) is
  • supplemental oxygen
  • bedside ultrasound for acute respiratory failure in critically ill patients prior to emergent needle aspiration for decompression followed by thoracostomy/chest tube placement
  • hospitalize
• primary pneumothorax
  • observation for spontaneous primary pneumothorax
    • occupying < 15% of hemithorax
    • < 2 cm air rim on chest X-ray; < 3.5 cm
    • without dyspnea or hypoxemia (asymptomatic)
    • avoid sudden changes in barometric pressure
      • airline travel
      • SCUBA diving
    • easy access to medical care should be available if condition deteriorates
    • pneumothorax detected only with CT, but not chest X-ray observed vs thoracostomy (65% vs 30%)
    • conservative management safe & effective
    • do not treat chest pain with NSAID
  • needle aspiration & high-flow supplemental oxygen
    • symptomatic primary spontaneous pneumothorax of any size
    • larger primary spontaneous pneumothorax (> 2 cm air rim on chest X-ray; > 3.5 cm)
    • fewer complications with needle aspiration than chest tube with similar likelihood of immediate success
    • failure at 24 hours more common with aspiration than chest tube (29 vs 18%) but similar 7 day & 1 year outcomes
  • ipsilateral thoracostomy +/- pleurodesis for 2nd spontaneous primary pneumothorax & for patients in high-risk occupations (scuba diving)
• secondary pneumothorax
  • hospitalize
    • small pneumothorax (< 2 cm) with minimal symptoms may be observed in an inpatient setting (< 3.5 cm)
  • chest tube drainage
    • aspiration through a plastic intercostal catheter
    • thoracostomy vs thoracoscopy with pleurodesis
    • chest tube drainage if > 3 cm air rim on chest X-ray
  • chemical pleurodesis
  • surgical decortication
• also see tension pneumothorax

More general terms

• pleural disorder

More specific terms

• hemopneumothorax
• pneumomediastinum; mediastinal emphysema
• pneumopericardium
• tension pneumothorax

Additional terms

• collapsed lung

Database

• OMIM: https://mirror.omim.org/entry/173600