Diagnosis

Pneumothorax

Etiology

Cause [f9e][hne]

1. Primary spontaneous pneumothorax: No underlying lung disease or trauma

   • Subclinical pleural blebs/bullae that may rupture and cause pneumothorax

   • Risk factors: pregnancy, tall, thin, male, smoker, age 18-40 years, Marfan syndrome

2. Seconday spontaneous pneumothorax: Underlying pulmonary pathology

   • Risk factors: COPD, asthma, HIV, pneumonia, tuberculosis, sarcoidosis, cystic fibrosis, lung cancer, pulmonary fibrosis, SARS, endometriosis (catamenial pneumothorax), Langerhans cell histiocytosis, lymphangioleiomyomatosis, connective tissue diseases (rheumatoid arthritis, scleroderma, Marfan syndrome, Ehlers-Danlos syndrome, ankylosing spondylitis, polymyositis/dermatomyositis)

3. Iatrogenic pneumothorax: thoracentesis, central venous catheter, tracheostomy, transbronchial biopsy, CT–guided needle lung biopsy, positive pressure ventilation (barotrauma), intercostal nerve block

4. Traumatic pneumothorax: blunt trauma (rib fracture), penetrating trauma, diving or flying

Pathophysiology [f9e]

1. Ventilation:

   • The pressure of the pleural space is negative compared to atmospheric pressure

   • The chest wall expands outwards --> the lung also expands outwards --> Air fills inside the lungs

2. Pneumothorax: Air in the pleural cavity can result in a collapse of the lung and impair oxygenation and/or ventilation

3. Tension pneumothorax: A life-threatening condition where air under positive pressure is trapped in the pleural cavity and the injured tissue forms a 1-way valve, allowing air inflow with inhalation into the pleural space and prohibiting air outflow. As the pressure increases --> ipsilateral lung collapses --> mediastinal shift --> contralateral lung collapse --> impaired venous return due to kinking of the inferior vena cava --> acute heart failure

   • Most common causes: blunt/penetrating trauma, positive pressure ventilation, pneumoperitoneum, bronchoscopy, tracheostomy

Complications [f9e]

• Respiratory failure

• Cardiac arrest

• Pyopneumothorax

• Empyema

• Rexpansion pulmonary edema

• Pneumopericardium

• Pneumoperitoneum

• Pneumohemothorax

• Bronchopulmonary fistula

• Hemorrhage during tube thoracostomy

• Skin infection at the site of tube thoracostomy

Epidemiology

Incidence per 100.000 [wdr][cy3][dpy][kis][f9e][g4s][dsr]

Approach

• Blood gas

• Chest x-ray

• CT thorax

• Contrast esophagography

• Chest ultrasonography

• Fluorescein-enhanced autofluorescence thoracoscopy

Treatment

1. Signs of instability --> needle decompression: [f9e]

   • 14- to 16-gauge and 4.5 cm in length angiocatheter

   • Flush above the rib in the 2nd intercostal space in the midclavicular line

   • Proceed with tube thoracostomy

2. Stable patient:

   • If asymptomatic and depth/size 1-2cm --> Watchful waiting or needle aspiration

   • If symptomatic or the depth/size >2cm --> Tube thoracostomy

     • Flush above the rib in the fifth intercostal space anterior to the midaxillary line

3. Indication for pleurodesis or bullectomy: VATS vs. thoracotomy vs laser treatment

   • Continuous air leak for >7 days

   • Bilateral pneumothoraces

   • High-risk profession patients (divers, pilots)

   • Recurrent ipsilateral pneumothorax

   • Contralateral pneumothorax

   • Patients who have AIDS

4. Open chest wounds:

   • Damage control: Three-sided occlusive dressing

   • Definitive surgery: Tube thoracostomy --> chest wall defect repair

Differential diagnoses

Acute respiratory distress syndrome, Aortic dissection, Asthma, Cardiac tamponade, COPD, Costochondritis, Esophageal perforation, Esophageal spasm, Fracture, Heart failure, Hemothorax, Lung abscess, Mediastinitis, Myocardial infarction, Myocarditis, Pericarditis, Pleural effusion, Pleuritis, Pneumomediastinum, Pneumonia, Pulmonary edema, Pulmonary embolism, Pulmonary empyema, Rib fracture, Tuberculosis