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

• Iatrogenic pneumothorax may follow procedures such as

  • Thoracentesis

  • Pleural biopsy

  • Subclavian or internal jugular vein catheter placement

  • Percutaneous lung biopsy

  • Bronchoscopy with transbronchial biopsy

  • Positive-pressure mechanical ventilation

• Risk factors for secondary pneumothorax include

  • Chronic obstructive pulmonary disease (COPD)

  • Asthma

  • Cystic fibrosis

  • Tuberculosis

  • Prior Pneumocystis pneumonia

  • Menstruation (catemenial pneumothorax)

  • Many interstitial lung diseases

• Tension pneumothorax usually occurs in the setting of

  • Penetrating trauma

  • Lung infection

  • Cardiopulmonary resuscitation

  • Positive pressure ventilation

Demographics

• Primary pneumothorax affects mainly tall, thin males between 10 and 30 years of age

• Family history and smoking may be contributing factors in primary spontaneous pneumothorax

Clinical Findings

Symptoms and Signs

• Chest pain ranges from minimal to severe

• Dyspnea is almost always present

• Symptoms usually begin at rest and resolve within 24 hours, even if the pneumothorax persists

• 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

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

• Secondary pleural effusion can occur

• Supine patients may demonstrate the "deep sulcus sign"—an abnormally radiolucent costophrenic angle

• Large amounts of subpleural air with contralateral mediastinal shift are present in tension pneumothorax

Treatment

Medications

• Symptomatic treatment is appropriate for cough and chest pain

• Supplemental oxygen may increase the rate ...