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Blast injuries
An explosion injures by four mechanisms — the pressure wave itself (primary), fragments (secondary), the victim being thrown (tertiary) and burns, crush and smoke inhalation (quaternary) — and the pressure wave mainly injures air-filled organs: the eardrum, the lungs and the bowel.
Why it matters in the exam
In Israel the topic is asked in the context of terror attacks and mass-casualty events: a patient who looks well after an explosion in an enclosed space, with a ruptured eardrum, who develops breathlessness and hypoxaemia over the following hours ("blast lung"). The question tests the understanding that lung injury can be delayed and that such patients must be observed.
Treatment principles are also tested: the standard ATLS approach, caution with fluids in blast lung, a chest drain for pneumothorax before positive-pressure ventilation or air transport, and suspicion of arterial air embolism when neurological signs or cardiac ischaemia appear after ventilation. An explosion in an enclosed space or a bus causes more severe primary injury than one in the open.
Remember that a ruptured eardrum is a marker of exposure to a significant pressure wave but predicts lung injury poorly; a patient with an isolated rupture, a normal chest X-ray and a normal examination can be discharged after a few hours of observation with return advice. Bowel injury from the pressure wave can present as a delayed perforation after days. Penetrating fragments need X-rays, wound care and a tetanus check, and many patients have several mechanisms at once.
In a mass-casualty setting remember the arrival pattern: the lightly injured arrive first on their own and the severely injured later, so the trauma bays should not be filled too early and the team must prepare for the second wave.
Key points
- Four mechanisms: pressure wave, fragments, being thrown, fire and crush.
- The pressure wave injures air-filled organs: ear, lung, bowel.
- Blast lung — hypoxaemia that may be delayed; cautious fluids.
- Chest drain before positive-pressure ventilation; suspect arterial air embolism.
- Isolated eardrum rupture with a normal examination — short observation and discharge.
Summary table
| Mechanism | Cause | Typical injuries | Emphasis |
|---|---|---|---|
| Primary | Pressure wave | Eardrum rupture, blast lung, bowel perforation, air embolism | More severe in an enclosed space |
| Secondary | Fragments and flying objects | Penetrating wounds anywhere | X-rays, tetanus, wound cleaning |
| Tertiary | Victim thrown | Fractures, head injury, blunt abdominal injury | Standard trauma approach |
| Quaternary | Fire, smoke, collapsing structures | Burns, smoke inhalation, crush and crush syndrome | Fluids, monitor potassium and kidney function |
A free exam question
במהלך פיגוע טרור התפוצץ מטען אשר הכיל חומר רדיואקטיבי. מספר נפגעים פונו למלר״ד. מבין הבאים, במי יש לטפל ראשון? (the question as examined, in Hebrew)
- א. STEMI עם כאב בחזה ואק״ג המדגים 62 בן
- ב. מ״מ כספית 120/60 עם חבלה בבטן ובבית החזה. לחץ דם 66 בת
- ג. בן 20 עם כוויות בפנים. מדבר לעניין וללא פחם בחלל הפה. יציב
- ד. עם רסיסים ברגל שמאל, צועקת. יציבה 8 בת
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Sources
- CDC, Explosions and Blast Injuries: A Primer for Clinicians, 2003 (current web edition) — Mechanisms of blast injury
- ATLS Advanced Trauma Life Support, Student Course Manual (American College of Surgeons), 10th edition (2018) — Initial assessment and management
- Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 9th edition (2020) — Blast injuries
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.