Spontaneous Pneumothorax

Spontaneous pneumothorax is air in the pleural space without trauma or iatrogenic cause. Primary occurs in patients without lung disease; secondary occurs with underlying lung disease.

• Primary spontaneous pneumothorax (PSP): tall, thin young men (15 to 35 years), smokers (risk 22 fold in men), rupture of apical subpleural blebs; incidence 7 per 100,000 per year in men, 1 in women.
• Secondary (SSP): COPD (commonest), cystic fibrosis, tuberculosis, Pneumocystis pneumonia, interstitial lung disease, Langerhans cell histiocytosis, lymphangioleiomyomatosis, necrotising pneumonia, Marfan syndrome, Ehlers Danlos, Birt Hogg Dubé, catamenial (thoracic endometriosis, right sided, within 72 hours of menses).
• Recurrence: 30% at 1 year after PSP; up to 50% overall; higher in SSP.
• Tension pneumothorax: air trapped with one way valve, mediastinal shift, cardiovascular collapse.
• Size: small under 2 cm from the apex to cupola (BTS: interpleural distance at hilum); large 2 cm or more (ACCP: apex to cupola 3 cm).

• Sudden unilateral pleuritic chest pain and dyspnoea, cough; may be mild in PSP; more severe in SSP.
• Reduced chest expansion, hyperresonance, reduced breath sounds and vocal resonance on the affected side.
• Tension: severe dyspnoea, tachycardia, hypotension, tracheal deviation, distended neck veins, cyanosis.
• Subcutaneous emphysema.

• Erect posteroanterior chest radiograph: visceral pleural line with absent lung markings beyond; expiratory film unnecessary.
• Bedside ultrasound: absent lung sliding, absent B lines, lung point.
• CT chest for uncertain cases, bullae, and planning (Birt Hogg Dubé, LAM, endometriosis); useful for recurrence evaluation.
• Oxygen saturation, arterial blood gas in SSP; ECG to exclude cardiac causes.
• Tension pneumothorax is a clinical diagnosis; do not delay treatment for imaging.

Tension pneumothorax

• Immediate needle decompression (14 gauge, 8 cm cannula in 4th or 5th intercostal space, anterior axillary line; or 2nd intercostal space mid clavicular line), followed by chest tube.

Primary spontaneous pneumothorax

• Small (under 2 cm), minimally symptomatic: observation with oxygen (high flow 10 L/min accelerates resorption 4 fold), outpatient follow up in 2 to 4 days.
• Large or symptomatic: needle aspiration (16 to 18 gauge cannula, 2nd intercostal space mid clavicular line or 4th to 5th in the safe triangle, aspirate up to 2.5 L) is as effective as chest drain (success 60 to 70%); if it fails, small bore chest drain (8 to 14 Fr, Seldinger) with underwater seal or Heimlich valve for ambulatory management.
• Persistent air leak beyond 5 to 7 days or recurrence: video assisted thoracoscopic surgery (bullectomy, apical blebectomy and pleurodesis (mechanical abrasion or talc 2 to 5 g) or pleurectomy); recurrence under 5% after VATS with pleurodesis vs 30% with drainage.
• Indications for definitive intervention: first ipsilateral recurrence, contralateral pneumothorax, bilateral simultaneous, persistent air leak, professions at risk (pilots, divers), or remote location.

Secondary spontaneous pneumothorax

• Admit, oxygen, chest drain (small bore 12 to 14 Fr) for most; needle aspiration only if under 2 cm and minimally breathless (age under 50); suction if no re-expansion (low pressure 10 to 20 cmH2O).
• Early thoracic surgery referral if air leak at 48 hours; surgical or chemical pleurodesis (talc slurry 4 to 5 g, doxycycline) at the first episode in patients unfit for surgery or with poor reserve.
• Treat the underlying disease; endobronchial valves for persistent air leak.

Advice

• Stop smoking; avoid air travel until 2 weeks after resolution on chest radiograph (1 week after VATS); permanent avoidance of scuba diving unless definitive surgical pleurectomy with normal lung function and CT; avoid contact sports for 4 weeks.
• Follow up in 2 to 4 weeks.