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For further information, see CMDT Part 9-36: Spontaneous Pneumothorax

Key Features

Essentials of Diagnosis

  • Acute onset of unilateral chest pain and dyspnea

  • Minimal physical findings in mild cases

  • Tension pneumothorax

    • Unilateral chest expansion

    • Decreased tactile fremitus

    • Hyperresonance

    • Diminished breath sounds

    • Mediastinal shift

    • Cyanosis

    • Hypotension

  • Pleural air on chest radiograph

General Considerations

  • Spontaneous pneumothorax occurs without trauma and is classified as

    • Primary: no prior lung disease

    • Secondary: complicating preexisting lung disease

  • Traumatic pneumothorax occurs as a result of penetrating or blunt trauma and includes iatrogenic pneumothorax following procedures such as

    • Thoracentesis

    • Pleural biopsy

    • Subclavian or internal jugular vein catheter placement

    • Percutaneous lung biopsy

    • Bronchoscopy with transbronchial biopsy

    • Positive-pressure mechanical ventilation

  • Secondary pneumothorax occurs as a complication of

    • COPD

    • Interstitial lung disease

    • Asthma

    • Cystic fibrosis

    • Tuberculosis

    • Pneumocystis pneumonia

    • Necrotizing bacterial pneumonia

    • Menstruation (catamenial pneumothorax)

    • Cystic lung diseases, including

      • Lymphangioleiomyomatosis

      • Tuberous sclerosis

      • Langerhans cell histiocytosis

      • Birt-Hogg-Dube syndrome (a hereditary condition with multiple benign skin tumors, lung cysts, and increased risk of both benign and malignant kidney tumors)

  • Tension pneumothorax usually occurs in the setting of

    • Penetrating trauma

    • Lung infection

    • Cardiopulmonary resuscitation

    • Positive pressure ventilation


  • Primary pneumothorax is more likely among tall, thin individuals, typically young men (age < 45 years)

  • Occurrence of primary spontaneous pneumothorax is correlated with

    • Cigarette smoking

    • Connective tissue disorders, such as Marfan and Ehlers-Danlos syndromes

Clinical Findings

Symptoms and Signs

  • Chest pain ranges from minimal to severe

  • Dyspnea is almost always present

  • Cough is commonly reported

  • In the setting of COPD or asthma, patients may present with life-threatening respiratory failure

  • Often seen with large pneumothoraces

    • Unilateral chest expansion

    • Hyperresonance

    • Diminished breath sounds

    • Decreased tactile fremitus

    • Decreased movement of the chest

  • Physical findings may be absent in small (< 15%) pneumothoraces

  • Tension pneumothorax should be suspected if marked tachycardia, mediastinal or tracheal shift, or hypotension is present

  • Crepitus may be found over the chest wall and adjacent structures

Differential Diagnosis

  • Emphysematous bleb mimicking loculated pneumothorax

  • Myocardial infarction

  • Pneumonia

  • Pulmonary embolism

  • Pneumomediastinum caused by rupture of the esophagus or bronchus

  • Upper respiratory tract infection

  • Rib fracture

  • Pericarditis

  • Mesothelioma


Laboratory Tests

  • Arterial blood gas usually reveals hypoxemia and acute respiratory alkalosis

  • Electrocardiogram: QRS axis and precordial T-wave changes may mimic acute myocardial infarction in left-sided pneumothorax

Imaging Studies

  • Chest radiography

    • Demonstration of lucency without lung markings between the chest wall and lung, and visualization of the visceral pleura (a "pleural line") is diagnostic

    • A characteristic air-fluid level is seen in a few patients with secondary pleural effusion

    • In supine patients, abnormally radiolucent costophrenic sulcus (the "deep sulcus" sign) may appear

    • In patients with tension pneumothorax, a ...

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