8. Pneumothorax

📄Definition

A pneumothorax is air in the pleural space, leading to partial or complete lung collapse.

Classification

🧠 Mnemonic: PATS

  • Primary Spontaneous (PSP) – no underlying lung disease (e.g. young, tall, thin men)

  • Acquired – traumatic or iatrogenic (e.g. central lines, ventilation)

  • Tension – emergency! Shift of mediastinum, ↓ venous return

  • Secondary Spontaneous (SSP) – underlying lung disease (e.g. COPD, ILD)

🔬 Pathophysiology

  • Rupture of pleural blebs or trauma → air leaks into pleural space

  • ↓ Negative pressure → lung collapse

  • Tension type: air enters on inspiration but can’t escape → ↑ pressure → cardiac arrest risk

🛡️ Risk Factors

🧠 Mnemonic: RUPTURED LUNG

  • Respiratory disease (COPD, asthma, ILD, CF)

  • Underweight (tall, thin males – PSP)

  • Pressure changes (scuba diving, flying)

  • Trauma (rib fracture, stab wound)

  • Unit interventions (e.g. central line, mechanical ventilation)

  • Recent smoking

  • Endometriosis (catamenial)

  • Drug use (cocaine, inhaled substances)

📋Clinical features

🧠 Mnemonic: PACT

  • Pleuritic chest pain (sudden onset, sharp)

  • Acute dyspnoea

  • Cough (dry)

  • Tachypnoea

🩺 Physical Examination

  • ↓ Chest expansion

  • ↓ Breath sounds

  • Hyper-resonance to percussion

  • Tracheal deviation (if tension – away from affected side)

  • Tachycardia/hypotension in tension type

Diagnosis

1st-line = CXR

  • Visible visceral pleural line

  • No lung markings beyond line

  • >2 cm from lung edge at hilum = large pneumothorax

  • Tension: mediastinal shift, ↓ lung field (clinical diagnosis — don’t wait for imaging)

CT Chest – if uncertain or underlying pathology suspected
ABG – for secondary pneumothorax (e.g. COPD)

Management (BTS/NICE-aligned)

🧠 Mnemonic: STOP-AIR

  1. Small PSP (<2 cm, no SOB) → discharge with safety-net

  2. Tension → immediate needle decompression (2nd ICS MCL) + chest drain

  3. Oxygen 15L if breathless (aids reabsorption)

  4. PSS or large PSP (>2 cm or SOB) → aspiration 1st-line

  5. Aspiration fails → chest drain (ICD)

  6. ICD management: monitor bubbling, swinging, suction as needed

  7. Refer to thoracic surgeon if persistent air leak (>5 days) or recurrent pneumothorax

📅 Follow-Up

  • Review within 2–4 weeks post-discharge

  • Smoking cessation advice essential

  • Warn against air travel for 1 week post-resolution

  • Diving contraindicated unless bilateral pleurectomy

❗Complications

  • Tension pneumothorax → cardiac arrest

  • Re-expansion pulmonary oedema

  • Infection

  • Recurrence (esp. in PSP)

🧐 Differential 

🧠 Mnemonic: PAST LUNG COLLAPSE

  • PE

  • Asthma exacerbation

  • Spontaneous rupture of bulla

  • Tension pneumothorax

  • LUNG malignancy

  • CHF

  • Oesophageal rupture

  • Lobar pneumonia

  • Lung abscess

  • Aspiration

  • Pleural effusion

  • Sarcoidosis

  • Empyema

🔎 Key PARA Exam Traps

💡 Sudden pleuritic chest pain + breathlessness = suspect pneumothorax

💡 Primary spontaneous pneumothorax → young, tall, thin patient: Smoking increases risk

💡 Secondary pneumothorax → underlying lung disease (e.g. COPD) Often more severe

💡 Tension pneumothorax is a clinical diagnosis: Do not wait for imaging

💡 Needle decompression first in suspected tension pneumothorax

💡 Reduced breath sounds + hyper-resonance on affected side

💡 CXR confirms diagnosis, but CT may be needed if uncertain

💡 Oxygen accelerates pneumothorax resolution

💡 Persistent air leak or recurrent pneumothorax → surgical referral

💡 Air travel and diving contraindicated until fully resolved

Last updated in line with NICE CG121 & BTS Pneumothorax Guidelines (2023)
Published: January 2015 • Last updated: August 2023

  • PARA-aligned, reviewed February 2026


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