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

Demographics

• 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

Diagnosis

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 ...