Spontaneous Pneumothorax: Causes and Treatment
Spontaneous pneumothorax should be treated based on its classification (primary vs. secondary), size, and the patient's clinical stability, with simple aspiration recommended as first-line treatment for primary pneumothoraces requiring intervention and chest tube drainage for secondary pneumothoraces. 1
Definition and Classification
Spontaneous pneumothorax is defined as the presence of air in the pleural space without antecedent traumatic or iatrogenic cause 1. It is classified into two main types:
- Primary spontaneous pneumothorax (PSP): Occurs in patients with no clinically apparent underlying lung abnormalities
- Secondary spontaneous pneumothorax (SSP): Occurs in patients with clinically apparent underlying lung disease, commonly COPD 1
Causes
Primary Spontaneous Pneumothorax
- Typically occurs due to rupture of small subpleural blebs or bullae, usually located at the lung apex
- Most common in tall, thin young adults (18-40 years)
- Risk factors include:
- Male gender
- Smoking
- Family history
- Low body mass index
Secondary Spontaneous Pneumothorax
- Results from underlying lung pathology
- Common causes include:
- COPD/emphysema (most common)
- Cystic fibrosis
- Interstitial lung disease
- Tuberculosis
- Pneumocystis jirovecii pneumonia (particularly in HIV patients)
- Lung cancer
Clinical Presentation
- Sudden onset of chest pain
- Dyspnea (shortness of breath)
- Decreased breath sounds on affected side
- Hyperresonance to percussion
- Tachycardia
- In severe cases, hypoxemia and respiratory distress
Diagnosis
- Chest X-ray (upright) is the primary diagnostic tool
- CT scan may be used in complex cases or to identify underlying lung disease
- Size assessment: Small pneumothorax is <3 cm apex-to-cupola distance; large is ≥3 cm 1
Treatment
1. Primary Spontaneous Pneumothorax
Small, Minimally Symptomatic:
- Observation alone is appropriate 1
- No hospitalization required, but patient should be instructed to return if breathlessness develops
- High-flow oxygen (10 L/min) may accelerate reabsorption if hospitalized 1
Large or Symptomatic:
- Simple aspiration is recommended as first-line treatment 1
- Using a cannula (≥16 French gauge, at least 3 cm long)
- Discontinue if resistance is felt, patient coughs excessively, or >2.5 L is aspirated 1
- Success rate: 60-70%
- If aspiration fails, proceed to small-bore chest tube (≤14F) or 16F-22F chest tube 1
2. Secondary Spontaneous Pneumothorax
Small, Minimally Symptomatic:
- Observation only recommended for pneumothoraces <1 cm depth or isolated apical pneumothoraces 1
- Hospitalization is required
- High-flow oxygen (with caution in COPD patients) 1
All Other Cases:
- Chest tube drainage (16F-22F) is the standard treatment 1
- Simple aspiration may be attempted in small (<2 cm) pneumothoraces in minimally breathless patients under 50 years 1
- Larger tubes (24F-28F) may be needed for patients with large air leaks or those requiring positive-pressure ventilation 1
3. Tension Pneumothorax
- Medical emergency requiring immediate decompression
- Insert cannula into second intercostal space in mid-clavicular line
- Follow with formal chest tube placement 1
4. Special Considerations
Cystic Fibrosis:
- Aggressive treatment recommended
- Consider surgical intervention after first episode if patient is fit 1
- Partial pleurectomy has 95% success rate 1
Prevention of Recurrence
- Chemical pleurodesis through chest tube (talc is most effective)
- Surgical options:
- Video-assisted thoracoscopic surgery (VATS) with bullectomy and pleurodesis
- Open thoracotomy with pleurectomy for complex cases 2
- Consider definitive measures after first recurrence for primary pneumothorax 3
- For secondary pneumothorax, consider pleurodesis after first episode 3
Post-Treatment Care
- Avoid air travel until chest radiograph confirms complete resolution 1
- Permanently avoid diving unless bilateral surgical pleurectomy has been performed 1
- Follow-up chest radiograph after 2 weeks if discharged without intervention 1
- Smoking cessation counseling to reduce recurrence risk 2
Common Pitfalls to Avoid
- Failing to recognize tension pneumothorax (requires immediate intervention)
- Underestimating small pneumothoraces in patients with underlying lung disease
- Delaying specialist referral for patients with persistent air leak (>48 hours)
- Not considering surgical referral after 5-7 days of persistent air leak 2
- Overlooking the need for close monitoring of patients on suction 2