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Stem
A 22-year-old tall, thin male smoker presents to the emergency department with sudden onset of right-sided pleuritic chest pain and breathlessness that began at rest two hours ago. On examination he is distressed, respiratory rate 28, SpO₂ 92% on room air, BP 124/76, pulse 104. The right hemithorax is hyper-resonant with reduced breath sounds and reduced vocal resonance; the trachea is central.
Questions
a) What is the most likely diagnosis, and on what two findings do you base it? (2 marks)
Diagnosis: primary spontaneous pneumothorax (right).
Basis:
- Sudden pleuritic chest pain with dyspnoea in the classic host — tall, thin, young male smoker.
- Hyper-resonance with reduced breath sounds and reduced vocal resonance on the affected side — air in the pleural space replacing ventilated lung.
b) Classify pneumothorax by aetiology and state which type this is. (2 marks)
By aetiology:
- Primary spontaneous (PSP) — no underlying lung disease (apical subpleural bleb).
- Secondary spontaneous (SSP) — underlying disease (COPD, asthma, cystic fibrosis, Pneumocystis, TB, LAM).
- Traumatic — blunt or penetrating chest trauma.
- Iatrogenic — central line, biopsy, mechanical ventilation/barotrauma.
- Tension — a complication of any type (one-way valve), not a separate aetiology.
This is a primary spontaneous pneumothorax.
c) How would you investigate and size this pneumothorax? (2 marks)
- Erect PA chest X-ray — diagnostic; shows the pleural line with absent lung markings beyond it.
- BTS size cut: measure the interpleural distance at the level of the hilum — under 2 cm = small; 2 cm or more = large (≈50% collapse). The CHEST guideline uses apex-to-cupola 3 cm or more for large.
- Pulse oximetry / ABG to quantify hypoxaemia; CT only if the diagnosis is doubtful or a bulla is suspected.
d) Outline the stepwise management of this patient. (4 marks)
Per the BTS 2023 guideline, management is size- and symptom-driven:
- Supplemental high-flow oxygen (10 to 15 L/min via non-rebreather, target SpO₂ 94 to 98%) — accelerates pleural air reabsorption roughly fourfold by nitrogen washout (avoid in CO₂-retainers, not relevant here).
- If small (under 2 cm) and asymptomatic — observe and discharge with safety-net advice and review in 2 to 4 weeks. This patient is symptomatic so:
- Large (2 cm or more) or symptomatic PSP — simple needle aspiration first-line: 16G cannula in the 2nd intercostal space, mid-clavicular line, aspirate up to 2.5 L (stop earlier if resistance/coughing). If successful (symptomatic relief + radiological re-expansion) observe and discharge.
- If aspiration fails — small-bore (8 to 14 Fr) Seldinger intercostal drain through the safe triangle (4th to 5th ICS, anterior mid-axillary line), connected to an underwater seal.
- Persistent air leak beyond 3 to 5 days, or a second ipsilateral recurrence — surgical pleurodesis (VATS) plus bullectomy.
- Lifestyle advice — stop smoking (halves recurrence); no air travel until CXR clear; never scuba dive without definitive surgery.
Additional high-yield SAQ prompts
SAQ — Tension pneumothorax. A ventilated ICU patient suddenly becomes hypotensive (BP 78/40), hypoxic (SpO₂ 84%), with the peak airway pressure rising from 22 to 42 cmH₂O and reduced air entry on the right.
- Diagnosis: tension pneumothorax (right) — a clinical diagnosis; do not wait for imaging.
- Immediate action: needle decompression — large-bore needle/catheter at the 2nd ICS MCL or 5th ICS, anterior mid-axillary line; the rush of air confirms tension. Convert immediately to a definitive intercostal chest drain.
- Resuscitation: high-flow oxygen, IV access, treat the obstructive shock with cautious fluids while decompressing.
- Pitfall: in the ventilated patient the classic triad may be absent — rising airway pressure, hypotension and hypoxia are the clues.
SAQ — Recurrence and prevention. A 26-year-old man has had his second right-sided primary spontaneous pneumothorax in 8 months.
- Recurrence rate of PSP: approximately 30% after a first episode (and again ~30% after a second).
- Indications for surgical pleurodesis (VATS): second ipsilateral PSP, first contralateral PSP, persistent air leak beyond 3 to 5 days, SSP at first presentation, bilateral pneumothorax, and high-risk occupations (pilots, divers) after a first event.
- Procedure: VATS bullectomy of apical blebs plus mechanical/abrasive pleurodesis (recurrence under 5%). Chemical pleurodesis (talc slurry, minocycline) is the alternative for unfit patients — the Chen 2013 Lancet RCT showed minocycline after aspiration reduced recurrence.
- Lifestyle: stop smoking; no flying until CXR clear; no diving without surgery.