Blast Injuries Practice Questions

25 multiple-choice questions on Blast injuries for paramedic and EMT students, from Chapter 30 (Trauma Systems and Mechanism of Injury). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. Primary blast injuries are caused by:

   1. A. Flying debris and shrapnel
   2. B. The body being thrown into objects
   3. C. The pressure wave of the explosion
   4. D. Burns and toxic smoke inhalation
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   Answer: C. The pressure wave of the explosion

   The overpressure wave damages tissues at air-fluid interfaces. Flying debris causes secondary blast injury, the most common type overall.

2. Primary blast injury most affects which organs?

   1. A. Air-filled organs: lungs, ears, and bowel
   2. B. Solid organs such as the liver and spleen
   3. C. Long bones of the arms and legs
   4. D. The skin and subcutaneous tissue
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   Answer: A. Air-filled organs: lungs, ears, and bowel

   Pressure differences tear tissue where air meets fluid. Solid organs are less compressible and are more often hurt by tertiary blunt forces.

3. The organ most often injured by the primary blast wave is the:

   1. A. Alveolar lung tissue
   2. B. Small bowel wall
   3. C. Tympanic membrane
   4. D. Globe of the eye
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   Answer: C. Tympanic membrane

   The eardrum ruptures at low pressures, causing hearing loss and tinnitus. Lung injury is less common but is the most common fatal primary blast injury.

4. A patient near an explosion has intact tympanic membranes. This finding:

   1. A. Proves that no blast lung injury is present
   2. B. Does not rule out serious blast injury
   3. C. Means the patient was beyond the blast radius
   4. D. Rules out any intestinal or lung blast injury
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   Answer: B. Does not rule out serious blast injury

   Earlier teaching used ear injury as a marker, but blast lung and bowel injury can occur without tympanic membrane rupture. Every exposed patient needs assessment and observation.

5. A 30-year-old man was 15 feet from a bomb blast in a shopping mall. Which presentation suggests blast lung?

   1. A. Wheezing that resolves with albuterol
   2. B. Pleuritic pain with a normal SpO2
   3. C. A barking cough and stridor
   4. D. Dyspnea, hemoptysis, and hypoxia
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   Answer: D. Dyspnea, hemoptysis, and hypoxia

   Alveolar rupture and hemorrhage cause respiratory distress, coughing up blood, and hypoxia, sometimes delayed for hours. Wheezing alone that responds to a bronchodilator suggests reactive airway disease.

6. A danger of positive-pressure ventilation in a patient with blast lung is:

   1. A. Air embolism and pneumothorax
   2. B. Bronchospasm and wheezing
   3. C. Atelectasis and alveolar collapse
   4. D. Bowel perforation and peritonitis
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   Answer: A. Air embolism and pneumothorax

   Damaged alveoli next to vessels can let air into the circulation under pressure, causing stroke or MI. Use the lowest pressures that maintain oxygenation. Positive pressure tends to reopen collapsed alveoli rather than cause atelectasis, it does not trigger bronchospasm, and it does not perforate the bowel.

7. A blast victim suddenly develops a focal neurologic deficit and chest pain. You should suspect:

   1. A. Simple tension pneumothorax
   2. B. Arterial air embolism
   3. C. Acute hypoglycemia
   4. D. Spinal shock
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   Answer: B. Arterial air embolism

   Air entering pulmonary veins travels to coronary and cerebral arteries. Tension pneumothorax causes respiratory distress and shock but not focal neurologic signs.

8. Secondary blast injuries are caused by:

   1. A. The overpressure shock wave
   2. B. Being thrown against a wall
   3. C. Flying debris and bomb fragments
   4. D. Toxic gases and burns from the fireball
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   Answer: C. Flying debris and bomb fragments

   Shrapnel, glass, and nails cause penetrating injury, the most common cause of injury and death in blasts. Being thrown against objects is tertiary blast injury.

9. A patient was thrown 20 feet into a wall by an explosion. This is a:

   1. A. Tertiary blast injury
   2. B. Primary blast injury
   3. C. Secondary blast injury
   4. D. Quaternary blast injury
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   Answer: A. Tertiary blast injury

   Tertiary injuries result from the body being displaced, causing blunt trauma, fractures, and amputations. Primary injuries come from the pressure wave itself.

10. Quaternary blast injuries include:

    1. A. Ear and lung pressure injuries
    2. B. Shrapnel wounds from the bomb casing
    3. C. Fractures from being thrown
    4. D. Burns, toxic inhalation, and crush
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    Answer: D. Burns, toxic inhalation, and crush

    Quaternary covers all other injuries, including burns, building collapse, inhaled toxins, and worsening of chronic illness such as asthma. Shrapnel wounds are secondary.

11. Some sources describe quinary blast injury, which refers to:

    1. A. The second pressure wave in an enclosed space
    2. B. Hearing loss that appears weeks later
    3. C. Illness from added chemicals or radiation
    4. D. Injuries to rescuers from secondary devices
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    Answer: C. Illness from added chemicals or radiation

    Quinary injury is a hyperinflammatory state or illness from chemical, biological, or radiological material added to the explosive. A delayed hearing loss is a late primary effect.

12. High-order explosives differ from low-order explosives because they:

    1. A. Burn slowly without producing a pressure wave
    2. B. Produce a supersonic overpressure shock wave
    3. C. Mainly cause burn and inhalation injuries
    4. D. Include pipe bombs and black gunpowder
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    Answer: B. Produce a supersonic overpressure shock wave

    TNT, C-4, nitroglycerin, and ammonium nitrate fuel oil detonate with a true blast wave. Low-order explosives such as pipe bombs and gunpowder deflagrate and lack this wave.

13. Blast injuries are more severe when the explosion occurs:

    1. A. In an enclosed space such as a bus
    2. B. In an open field far from buildings
    3. C. Under water with victims on land
    4. D. In warm weather rather than cold
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    Answer: A. In an enclosed space such as a bus

    Walls reflect and amplify the pressure wave and concentrate debris, so injuries and deaths increase. Open-air blasts dissipate energy quickly.

14. A blast victim is underwater during an explosion. Compared with the same blast in air, the injuries are:

    1. A. Less severe because water absorbs the wave
    2. B. Limited to the ears and eyes
    3. C. The same as an open-air blast
    4. D. More severe at a greater distance
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    Answer: D. More severe at a greater distance

    Water is incompressible and carries the pressure wave farther, so underwater blasts cause severe injuries over a wider range. The wave is not absorbed.

15. A patient was 10 feet from an explosion in a café. He has abdominal pain and tenderness but no external wounds. You should suspect:

    1. A. Primary blast injury of the bowel
    2. B. Secondary blast injury from shrapnel
    3. C. An abdominal muscle strain
    4. D. Quaternary injury from toxic gas
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    Answer: A. Primary blast injury of the bowel

    The pressure wave can perforate or bruise the bowel, with symptoms that may be delayed. Without visible wounds, blast-induced hollow organ injury is easy to miss. Secondary injury requires a penetrating wound from debris, toxic gas does not explain localized abdominal tenderness, and a muscle strain should not be assumed after a blast.

16. At a bombing scene, the greatest immediate threat to rescuers is often:

    1. A. Radiation from the first explosion
    2. B. Fire spreading outward from the blast site
    3. C. A secondary device aimed at responders
    4. D. Hypothermia during extrication
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    Answer: C. A secondary device aimed at responders

    Terrorists may place a second device to injure EMS, police, and fire responders. Stage at a safe distance and enter only when law enforcement clears the scene.

17. After an explosion, a woman has a nail impaled in her thigh, bilateral eardrum rupture, and a burn. Her injuries include:

    1. A. Primary and tertiary injuries
    2. B. Secondary, tertiary, and quaternary
    3. C. Tertiary and quaternary injuries
    4. D. Primary, secondary, and quaternary
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    Answer: D. Primary, secondary, and quaternary

    Eardrum rupture is primary, the nail is secondary, and the burn is quaternary. Blast patients commonly have more than one injury category.

18. In a blast, traumatic amputation of a limb is most often due to:

    1. A. Toxic gas exposure in an enclosed space
    2. B. Combined blast wave and tertiary forces
    3. C. Burns from the fireball and flash
    4. D. Quinary radiation exposure effects
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    Answer: B. Combined blast wave and tertiary forces

    The blast wave fractures the bone and the blast wind then avulses the limb. Amputation predicts severe internal injury and higher mortality.

19. A blast victim with dyspnea and hemoptysis but stable blood pressure should receive:

    1. A. Large volumes of fluid to prevent shock
    2. B. High-pressure ventilation via BVM
    3. C. Prophylactic needle decompression
    4. D. Oxygen and careful fluid administration
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    Answer: D. Oxygen and careful fluid administration

    Excess fluids worsen pulmonary edema and hemorrhage in blast lung, so give fluids only as needed to keep perfusion. High-pressure ventilation risks air embolism.

20. A survivor of a nearby explosion has ringing in both ears and minimal hearing. He also seems confused. You should consider:

    1. A. That he is ignoring your commands on purpose
    2. B. An acute stress reaction
    3. C. Traumatic brain injury from the blast
    4. D. Normal results of loud noise
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    Answer: C. Traumatic brain injury from the blast

    Blast waves can cause concussion and other TBI even without head impact. Confusion may also reflect hearing loss, so test with written instructions too.

21. The blast wind is:

    1. A. The heat produced by the explosion
    2. B. Rapid movement of air after the pressure wave
    3. C. Toxic gases released from the device as it burns
    4. D. A slow burn after deflagration
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    Answer: B. Rapid movement of air after the pressure wave

    The blast wind pushes victims and debris, contributing to secondary and tertiary injury. Heat contributes to quaternary burns.

22. Why may blast victims with severe injuries appear stable on initial assessment?

    1. A. Lung, bowel, and brain injury may be delayed
    2. B. Blast injuries are generally minor ones
    3. C. Blast injuries seldom cause internal bleeding
    4. D. Pain from blast injury resolves within minutes
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    Answer: A. Lung, bowel, and brain injury may be delayed

    Blast lung and bowel injury can appear hours later, so patients need observation and reassessment. Underestimating them is a common error.

23. In a mass-casualty bombing, many of the first patients to arrive at the nearest hospital tend to be:

    1. A. The most critically injured patients first
    2. B. Patients brought in by air medical crews
    3. C. Victims who were triaged black at the scene
    4. D. Less injured patients who left on their own
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    Answer: D. Less injured patients who left on their own

    Walking wounded often self-transport and can overwhelm the closest hospital before EMS arrives. EMS should coordinate destinations to spread the load.

24. A patient injured in a bomb explosion has asthma that became worse after the event. This is classified as a:

    1. A. Primary blast injury
    2. B. Secondary blast injury
    3. C. Quaternary blast injury
    4. D. Tertiary blast injury
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    Answer: C. Quaternary blast injury

    Quaternary injury includes worsening of chronic conditions such as asthma, COPD, and angina, along with burns and inhalation. Primary injuries are from the pressure wave.

25. Bombs packed with nails and ball bearings are designed to increase:

    1. A. Primary blast injuries
    2. B. Secondary blast injuries
    3. C. Tertiary blast injuries
    4. D. Quaternary blast injuries
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    Answer: B. Secondary blast injuries

    Added projectiles increase penetrating injuries and casualties. These do not change the pressure wave that causes primary injury.