Pneumothorax - A Complete Guide with Images

1. Definition

2. Classification

A. Spontaneous Pneumothorax

Primary Spontaneous Pneumothorax (PSP)

• Occurs with no clinically apparent underlying lung disease
• Typical patient: tall, thin young male (3x more common in men)
• Caused by rupture of subpleural blebs - small thin-walled air pockets
• Risk factors: smoking, Marfan syndrome, mitral valve prolapse, changes in atmospheric pressure
• Incidence approximately 7.4/100,000/year in men; 1.2/100,000/year in women

Secondary Spontaneous Pneumothorax (SSP)

• Occurs on a background of existing lung disease
• Most common cause in the US: COPD (emphysematous bullae rupture)
• Other causes include:
  • Asthma, cystic fibrosis
  • Pneumocystis jirovecii pneumonia (HIV patients)
  • Tuberculosis and lung abscess (developing countries)
  • Connective tissue diseases (Marfan, Ehlers-Danlos)
  • Malignancy, sarcoidosis, lymphangioleiomyomatosis

B. Traumatic Pneumothorax

• 15-50% of patients with significant chest trauma
• Three subtypes based on the relationship with the atmosphere:

1. Simple (Closed) Pneumothorax

• No communication with the atmosphere
• No mediastinal shift
• Usually caused by a rib fracture lacerating the pleura, or a blow at full inspiration with the glottis closed ("paper bag effect")

2. Communicating (Open) Pneumothorax - "Sucking Chest Wound"

• Chest wall defect creates a direct communication with the atmosphere
• Mostly from gunshot wounds or combat injuries

3. Tension Pneumothorax

• A one-way valve effect - air enters on inspiration but cannot exit on expiration
• Air accumulates progressively under pressure, pushing the mediastinum to the opposite side
• Compresses the vena cava and distorts the cavoatrial junction - dramatically reduces venous return and cardiac output
• Life-threatening emergency

C. Iatrogenic Pneumothorax

• Complication of central line placement, thoracentesis, lung biopsy, mechanical ventilation (barotrauma), post-procedure

3. Pathophysiology

1. Negative intrapleural pressure is lost
2. The ipsilateral lung collapses (elastic recoil)
3. Vital capacity and functional residual capacity drop
4. Ventilation-perfusion mismatch causes hypoxemia

• Ipsilateral lung total collapse
• Mediastinal shift contralaterally
• Compression of contralateral lung
• Kinking and compression of the vena cava → decreased preload → shock
• Rapid onset of hypoxia, acidosis, cardiovascular collapse, and death if untreated

4. Clinical Features

Symptoms

Signs on Examination

Tension Pneumothorax - The Classic Triad

Tracheal deviation + absent breath sounds (ipsilateral) + hypotension = Tension pneumothorax until proven otherwise. Treat first, confirm later.

5. Imaging

Chest X-Ray

• Visible visceral pleural line (thin white line parallel to chest wall) with no lung markings beyond it
• Collapsed lung toward the hilum
• If tension: tracheal deviation, depressed ipsilateral hemidiaphragm, contralateral mediastinal shift

CT Chest

• Occult pneumothorax suspected
• Need to distinguish pneumothorax from bullous emphysema
• Loculated collections requiring image-guided drainage
• Pre-surgical planning

Ultrasound (POCUS)

6. Sizing

7. Management

Algorithm Overview

Pneumothorax confirmed
    ├── Tension pneumothorax? → IMMEDIATE DECOMPRESSION (don't wait for CXR!)
    │
    ├── Traumatic? → Tube thoracostomy (24 Fr or pigtail via Seldinger)
    │
    └── Spontaneous?
          ├── Small + asymptomatic + PSP → Observation, repeat CXR in 4-6h
          │
          ├── Large or symptomatic PSP → Aspiration or chest tube
          │
          └── Any SSP → Chest tube (higher risk of tension with PPV)

Tension Pneumothorax - Emergency Treatment

1. Needle decompression (temporizing):
   • 14-16G IV catheter (minimum 5 cm length)
   • 2nd intercostal space, midclavicular line OR 4th/5th ICS, midaxillary line
   • Air escaping under pressure = confirms diagnosis
   • Follow immediately with chest tube
2. Finger/tube thoracostomy (definitive):
   • May be done directly in the ED - often faster than needle decompression

Chest Tube (Tube Thoracostomy)

• Traumatic pneumothorax (except small asymptomatic apical)
• Moderate-to-large pneumothorax
• Respiratory symptoms, any size
• Pneumothorax on positive pressure ventilation
• Increasing size after initial observation
• Recurrence after previous chest tube

• Small-bore tube (24 Fr) or pigtail catheter (Seldinger technique) for simple pneumothorax
• Connected to water-seal drainage unit with suction at -20 cmH2O
• Reduce to water seal only once air leak stops
• Clamp test for 4 hours; remove if CXR clear
• Air leak persisting >4-7 days = tube failure → surgical intervention

Recurrence Prevention

• Recurrence rate ~30% after first episode
• Options: pleurodesis (sclerosing agent instilled or mechanical abrasion), surgical resection of apical blebs/bullae (via VATS)
• Pleurodesis recommended after second episode or first episode in high-risk patients (pilots, divers)

Disposition

8. Complications

• Tension pneumothorax - if simple pneumothorax not managed on PPV
• Reexpansion pulmonary edema - rare, after rapid evacuation of large chronic pneumothorax
• Hemopneumothorax - blood + air in pleural space (from torn adhesions in recurrent PSP)
• Bronchopleural fistula - persistent air leak
• Recurrence (~30%)

9. Quick Comparison Table

• Rosen's Emergency Medicine, 9e, Chs. 37 & 63
• Murray & Nadel's Textbook of Respiratory Medicine (POCUS section)
• Roberts & Hedges' Clinical Procedures in Emergency Medicine
• Goldman-Cecil Medicine, International Edition