Closed Injuries: Contusions, Hematomas, Crush Injury, and Compartment Syndrome Practice Questions

25 multiple-choice questions on Closed injuries: contusions, hematomas, crush injury, and compartment syndrome for paramedic and EMT students, from Chapter 32 (Soft-Tissue Trauma). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. A closed soft-tissue injury is one in which:

   1. A. The skin surface remains intact
   2. B. The bone is broken but not exposed
   3. C. The wound has been bandaged
   4. D. There is no internal bleeding
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   Answer: A. The skin surface remains intact

   Closed injuries damage tissue beneath unbroken skin. They can still involve severe internal bleeding, so the no-bleeding option is a dangerous misconception.

2. A contusion is best described as:

   1. A. A scrape that removes the epidermis
   2. B. A flap of skin torn loose
   3. C. Bleeding under intact skin
   4. D. A pocket of fluid from a burn
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   Answer: C. Bleeding under intact skin

   Blunt force ruptures small vessels in the dermis, producing swelling and discoloration called ecchymosis. A scrape that removes epidermis is an abrasion, which is an open injury.

3. Ecchymosis refers to:

   1. A. A pool of blood that forms a lump
   2. B. Blood discoloring the tissues
   3. C. Swelling caused by lymph fluid
   4. D. Hardening of the skin after injury
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   Answer: B. Blood discoloring the tissues

   Ecchymosis is the blue-black color of blood leaking into tissues, which later turns yellow-green as it breaks down. A distinct pool of blood forming a lump is a hematoma.

4. A hematoma differs from a simple contusion in that a hematoma:

   1. A. Requires an underlying fracture to form
   2. B. Is a pool of blood from larger vessels
   3. C. Has an open wound in the skin over it
   4. D. Contains serous fluid rather than blood
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   Answer: B. Is a pool of blood from larger vessels

   Hematomas form when larger vessels bleed into a tissue space, creating a palpable mass. They need not involve fracture, though fractures commonly cause them.

5. A closed femur fracture can produce a thigh hematoma containing approximately:

   1. A. 1,000 mL of blood
   2. B. 50 mL of blood
   3. C. 200 mL of blood
   4. D. 4,000 mL of blood
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   Answer: A. 1,000 mL of blood

   A femur fracture can hide about 1 L of blood in the thigh, enough to cause shock. 4,000 mL approaches total blood volume and is far too high for one closed thigh.

6. A 24-year-old was struck in the thigh by a baseball bat. The thigh is swollen and tender with intact skin, and vital signs are normal. Initial management should include:

   1. A. Heat packs to increase blood flow
   2. B. Massage to spread the swelling
   3. C. Ice, compression, and elevation
   4. D. Incision to drain the bruise
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   Answer: C. Ice, compression, and elevation

   Cold and compression constrict vessels and limit swelling; elevation helps venous drainage. Heat early on dilates vessels and increases bleeding and swelling, which is why it is the most tempting wrong choice.

7. When applying a cold pack to a contusion, you should:

   1. A. Apply the ice directly against the skin
   2. B. Leave it in place continuously for hours
   3. C. Use dry ice wrapped in a towel instead
   4. D. Place a cloth between the pack and skin
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   Answer: D. Place a cloth between the pack and skin

   A barrier and limited application periods prevent cold injury to the skin. Direct ice or prolonged cooling can cause frostbite-like tissue damage.

8. A crush injury differs from crush syndrome in that crush injury refers to:

   1. A. Systemic effects after the force is released
   2. B. Kidney failure from myoglobin
   3. C. Hyperkalemia causing dysrhythmias
   4. D. Local tissue damage from compression
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   Answer: D. Local tissue damage from compression

   Crush injury is the direct damage to the compressed tissue. Crush syndrome is the systemic illness, including hyperkalemia, acidosis, and myoglobinuric kidney injury, that appears when the compressed area is reperfused.

9. Crush syndrome is most likely to develop when:

   1. A. A finger is caught briefly in a door
   2. B. A thigh is pinned for several hours
   3. C. A hand is struck once with a hammer
   4. D. Skin is scraped against pavement
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   Answer: B. A thigh is pinned for several hours

   Crush syndrome needs a large muscle mass, such as a thigh or pelvis, compressed long enough for muscle to break down; risk begins after about an hour and rises with time, and 4 to 6 hours is the classic duration. Brief compression of a finger or hand, a single blow, or a scrape does not release enough potassium or myoglobin to cause systemic effects.

10. When a crushed limb is released, the electrolyte disturbance of most immediate concern is:

    1. A. Hyperkalemia
    2. B. Hypernatremia
    3. C. Hypercalcemia
    4. D. Hypokalemia
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    Answer: A. Hyperkalemia

    Dying muscle cells release potassium, which washes into the circulation on release and can cause lethal dysrhythmias. Hypocalcemia, not hypercalcemia, occurs because calcium is drawn into damaged muscle.

11. Myoglobin released from crushed muscle is dangerous because it can:

    1. A. Destroy red blood cells
    2. B. Raise the potassium level directly
    3. C. Damage the kidneys
    4. D. Bind oxygen and starve the tissue
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    Answer: C. Damage the kidneys

    Myoglobin precipitates in the renal tubules, especially in acidic, low-flow conditions, causing acute kidney injury and tea-colored urine. It does not destroy red cells; that would be hemolysis. The high potassium of crush syndrome comes from the injured muscle cells themselves rather than from myoglobin, and myoglobin does not starve the tissues of oxygen; its danger is in the kidney.

12. A 40-year-old man has been pinned under a collapsed wall by both legs for 5 hours. He is alert. Before the wall is lifted, the most important treatment is to:

    1. A. Apply cold packs to both legs
    2. B. Give oral fluids to drink
    3. C. Start IV normal saline
    4. D. Administer a loop diuretic
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    Answer: C. Start IV normal saline

    Aggressive IV normal saline before release dilutes the potassium and acids and protects the kidneys. A diuretic is tempting because it promotes urine flow, but it worsens volume depletion in a patient already sequestering fluid.

13. During extrication of a patient with prolonged compression of the legs, the ECG shows tall, peaked T waves after release. Along with fluids, you should anticipate giving:

    1. A. Adenosine and amiodarone
    2. B. Potassium chloride
    3. C. Furosemide and atropine
    4. D. Calcium and bicarbonate
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    Answer: D. Calcium and bicarbonate

    Peaked T waves after release signal hyperkalemia. Calcium stabilizes the cardiac cell membrane within minutes, and sodium bicarbonate corrects acidosis and lowers serum potassium; flush the line between them because they precipitate together. Adenosine and amiodarone treat other dysrhythmias and do nothing for potassium. Potassium chloride would worsen the problem. Furosemide depletes volume in a patient who needs fluid, and atropine does not treat hyperkalemia.

14. Before freeing a man whose legs have been pinned for 4 hours, you start IV fluid. Normal saline is generally preferred over lactated Ringer's here mainly because normal saline:

    1. A. Contains more calcium
    2. B. Contains no potassium
    3. C. Contains lactate as a buffer
    4. D. Is a colloid that stays in vessels
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    Answer: B. Contains no potassium

    Crush syndrome releases large amounts of potassium when the limb is freed, so potassium-free normal saline is the usual choice before and during release. Lactated Ringer's contains a small amount of potassium (and calcium and lactate), and normal saline is a crystalloid, not a colloid.

15. The urine of a patient with crush syndrome is often described as:

    1. A. Dark, tea-colored
    2. B. Bright red with clots
    3. C. Clear and dilute
    4. D. Milky white
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    Answer: A. Dark, tea-colored

    Myoglobin turns urine dark brown or tea-colored. Bright red urine with clots suggests direct trauma to the urinary tract instead.

16. A 45-year-old's thigh has been pinned under a steel beam for 3 hours. The beam can be lifted now, but you have been unable to obtain IV or IO access. Your local crush protocol permits a tourniquet on the trapped limb before release in this situation. Its purpose is to:

    1. A. Prevent compartment syndrome from developing in the thigh
    2. B. Hold potassium and acid in the limb until fluids run
    3. C. Restore blood flow to the crushed thigh muscles
    4. D. Raise the blood pressure enough for safe extrication
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    Answer: B. Hold potassium and acid in the limb until fluids run

    When fluids cannot be started before release, a few protocols (for example Los Angeles County 1242-P) allow a tourniquet that fully occludes arterial flow, placed before the load is lifted, so potassium, acid, and myoglobin stay in the limb until IV/IO access and fluids are running; it is then left for the hospital to remove. It is a last resort, and many guidelines (ACT CMG 30, Scotland CG017, the Renal Disaster Relief Task Force) reserve tourniquets for hemorrhage and insist on IV/IO fluid first, so follow your own protocol. It does not prevent compartment syndrome; it adds ischemia to an already injured limb. It stops flow rather than restoring it. It does not treat hypotension: the shock that follows release comes from fluid shifting into the limb and is prevented with volume, not a tourniquet.

17. A 25-year-old has an open tibia fracture with a 2-cm wound, and his calf is tense and becoming more painful. Regarding compartment syndrome, you should:

    1. A. Exclude it, since open fractures vent pressure
    2. B. Exclude it until the distal pulse is lost
    3. C. Suspect it only if the skin is fully intact
    4. D. Still suspect it; the wound may not relieve it
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    Answer: D. Still suspect it; the wound may not relieve it

    A small wound does not decompress all the closed compartments of the leg, so compartment syndrome can occur with open fractures. Severe pain and a tense compartment warrant reporting it. Loss of the distal pulse is a late sign, so waiting for it risks permanent muscle and nerve damage.

18. The earliest and most reliable sign of compartment syndrome is:

    1. A. Absent distal pulses in the limb
    2. B. Pallor of the skin over the limb
    3. C. Pain out of proportion
    4. D. Paralysis of the affected muscles
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    Answer: C. Pain out of proportion

    Severe pain that is greater than expected, especially on passive stretch, appears early. Absent pulses are tempting, but compartment pressure rarely exceeds arterial pressure until very late, so a pulse can be present with severe ischemia.

19. A patient with a tibia fracture has severe calf pain that worsens when you passively flex his toes. This most strongly suggests:

    1. A. Compartment syndrome
    2. B. A deep vein thrombosis
    3. C. A ruptured Achilles tendon
    4. D. A peripheral nerve laceration
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    Answer: A. Compartment syndrome

    Pain with passive stretch of the muscles in a compartment is a classic early sign. DVT can cause calf pain, but it is not triggered by a fresh fracture within hours and is not related to stretching the muscles.

20. A patient with a forearm fracture needs repeated doses of fentanyl, but his pain keeps getting worse after each dose. You should suspect:

    1. A. Opioid tolerance
    2. B. A splint too loose
    3. C. Compartment syndrome
    4. D. Normal fracture pain
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    Answer: C. Compartment syndrome

    Pain that escalates despite adequate analgesia, especially out of proportion to the injury and worse with passive stretch, is a key warning sign of compartment syndrome. Recheck the limb, loosen anything constricting, and report it. Assuming tolerance or normal fracture pain risks missing a surgical emergency, and a loose splint does not cause rising pain.

21. A patient with suspected compartment syndrome of the leg should have the extremity positioned:

    1. A. At the level of the heart
    2. B. Elevated well above the heart
    3. C. Hanging below the stretcher
    4. D. Tightly wrapped in a bandage
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    Answer: A. At the level of the heart

    Keeping the limb at heart level balances venous drainage and arterial inflow. Elevating it high, which is correct for simple swelling, lowers arterial pressure to an already ischemic compartment.

22. Definitive treatment of compartment syndrome is:

    1. A. Cold packs and elevation
    2. B. IV antibiotics
    3. C. A tight pressure bandage
    4. D. Fasciotomy
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    Answer: D. Fasciotomy

    Surgical opening of the fascia releases the pressure and restores flow. Cold and elevation do not relieve compartment pressure, and a tight bandage makes it worse.

23. A 22-year-old found down after a heroin overdose has been lying on his left arm for an unknown time. The forearm is tense, swollen, and very painful. You should suspect:

    1. A. Cellulitis from injection drug use
    2. B. Compartment syndrome
    3. C. A simple contusion of the forearm
    4. D. Gas gangrene of the forearm
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    Answer: B. Compartment syndrome

    Prolonged immobility from overdose can compress muscle and cause rhabdomyolysis and compartment syndrome. Cellulitis develops over days with warmth and redness, not acute tense swelling after lying on the limb.

24. A splint or cast that becomes too tight over a swelling limb can cause compartment syndrome. The appropriate field action is to:

    1. A. Elevate the limb above the heart
    2. B. Loosen it and recheck the limb
    3. C. Apply cold packs over the splint
    4. D. Give analgesia and leave it alone
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    Answer: B. Loosen it and recheck the limb

    Removing external compression is the first step and can relieve pressure. Analgesia alone is tempting, but it masks the key symptom while ischemia progresses.

25. Which finding in a patient with a crushed leg is a late sign of compartment syndrome?

    1. A. Tense, swollen compartment
    2. B. Pain on passive stretch
    3. C. Loss of the distal pulse
    4. D. Tingling in the foot
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    Answer: C. Loss of the distal pulse

    Pulselessness appears very late, after muscles and nerves are already ischemic. Paresthesia and pain on stretch appear early and should prompt action.