Tension Pneumothorax
Emergency Medicine
Illness script · Emergency Medicine
Tension Pneumothorax
Air trapped under pressure in the pleural space causing mediastinal shift, obstructive shock, and cardiorespiratory collapse.
This illness script for Tension Pneumothorax covers predisposing factors, classic presentation, mechanism, workup, management, and the clinical pivots that separate it from look-alikes—written for USMLE Step 1 and clerkship reasoning.
01
Predisposing factors
- Mechanical ventilation (positive pressure) — highest risk setting
- Penetrating or blunt chest trauma
- Spontaneous pneumothorax progressing with one-way valve mechanism
- Central line placement complication
- COPD/asthma with air-trapping, tall thin males
02
Presentation
- Acute respiratory distress with hypoxia and tachycardia
- Hypotension (obstructive shock) — the key 'tension' feature
- Absent/decreased breath sounds on ipsilateral side
- Tracheal deviation away from affected side (late, unreliable sign)
- Distended neck veins (JVD) — may be absent if hypovolemic
- Traumatic context: may present as PEA arrest
03
Pathophysiology
- One-way valve allows air into pleural space but not out
- Progressive pressure collapses ipsilateral lung
- Mediastinum shifts contralaterally, kinking great vessels (SVC/IVC)
- Venous return drops → obstructive shock → PEA arrest if untreated
04
Diagnostics
- Clinical diagnosis — DO NOT delay treatment for imaging
- CXR (if stable): hyperlucency, absent lung markings, mediastinal shift, flattened diaphragm
- Tracheal deviation on CXR is a late/unreliable sign — act before it appears
- POCUS: absent lung sliding + absent B-lines ipsilaterally, confirms quickly at bedside
- Pitfall: intubated patients may deteriorate suddenly — always suspect tension
05
Management
- Immediate needle decompression: 2nd ICS midclavicular line (or 4th–5th ICS anterior axillary line)
- Follow immediately with tube thoracostomy (28–36 Fr) — definitive treatment
- Needle decompression is temporizing only; chest tube placement must follow
- High-flow O2 and IV access concurrent with decompression
- Avoid prolonged positive-pressure ventilation without chest tube in place
06
Clinical pivots
How to separate this script from the look-alikes that show up on exams and on the wards.
Simple Pneumothorax
No hemodynamic instability, no JVD, no mediastinal shift — stable vitals distinguish simple from tension
Cardiac Tamponade
Both cause JVD + hypotension; absent breath sounds + asymmetric exam point to tension; tamponade has muffled heart sounds and no respiratory asymmetry
Massive Hemothorax
Dullness to percussion (not hyperresonance) and no JVD; hemothorax causes hemorrhagic rather than obstructive shock
Obstructive Shock (PE)
PE lacks unilateral absent breath sounds and asymmetric chest findings; tracheal deviation absent in PE
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Educational use only. This illness script is a study framework, not medical advice. Confirm decisions with current guidelines and your clinical supervisors.