Menu

2. Trauma MCQs

Practice Set 503 of 640

This practice set contains high-yield board review questions covering key concepts in 2. Trauma. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 10041

Topic: 2. Trauma

A 30-year-old athlete presents with exertional leg pain, which is relieved by rest. Physical exam reveals diminished pulses with provocative maneuvers (e.g., forced plantarflexion/dorsiflexion against resistance). The primary differential diagnosis is popliteal artery entrapment syndrome. What pressure measurement is crucial for confirming this diagnosis?

. Compartment pressures before and after exercise.
. Ankle-brachial index (ABI) at rest and after exercise.
. Popliteal artery pressure at rest and with provocative maneuvers.
. Intramuscular pressure of the gastrocnemius.
. Venous pressures in the lower extremity.

Correct Answer & Explanation

. Ankle-brachial index (ABI) at rest and after exercise.

Explanation

For popliteal artery entrapment syndrome, the key diagnostic test is a significant drop in the ankle-brachial index (ABI) or obliteration of pulses with provocative maneuvers (e.g., plantarflexion or dorsiflexion of the ankle). An ABI of <0.9 at rest, or a drop of >0.15-0.20 post-exercise, is highly suggestive. While compartment pressures are used for chronic exertional compartment syndrome, and popliteal artery pressure measurements could be technically challenging and less standardized, the ABI provides a practical and reliable indicator of arterial flow compromise. Options C, D and E are not standard diagnostic tests. Resting compartment pressures would be normal, and post-exercise pressures are specific for compartment syndrome, not arterial entrapment, although some conditions can coexist.

Question 10042

Topic: 2. Trauma

Which of the following statements about measuring intracompartmental pressures is FALSE?

. Needle placement should be within 1-2 cm of the fracture site.
. The catheter tip should lie freely within the muscle compartment.
. Measurements should be taken in multiple compartments if suspicion is high.
. The transducer should be zeroed at the level of the compartment being measured.
. Compartment pressure of 30 mmHg or greater is always an absolute indication for fasciotomy.

Correct Answer & Explanation

. Compartment pressure of 30 mmHg or greater is always an absolute indication for fasciotomy.

Explanation

A compartment pressure of 30 mmHg or greater is notalwaysan absolute indication for fasciotomy. The decision to perform fasciotomy should be based on a combination of clinical signs (the most important factor), a rising or high absolute pressure, and the delta pressure (diastolic blood pressure - intracompartmental pressure). For example, a patient with a systolic BP of 180 mmHg and a compartment pressure of 30 mmHg has a delta pressure of 150 mmHg, which is unlikely to be critical, whereas a patient with a DBP of 40 mmHg and a compartment pressure of 30 mmHg has a delta pressure of 10 mmHg, which is highly concerning. The other statements are correct principles for accurate intracompartmental pressure measurement.

Question 10043

Topic: 2. Trauma

A 10-year-old child sustains a supracondylar humerus fracture. Despite reduction and pinning, the child develops excruciating pain, pallor, pulselessness, paresthesias, and paralysis in the hand and forearm. What is the most likely diagnosis, and what intervention is urgently required to prevent permanent neurological and muscular damage, primarily addressing tissue pressure?

. Radial nerve palsy; observation and physiotherapy.
. Volkmann's ischemic contracture; serial casting.
. Acute compartment syndrome; emergency fasciotomy.
. Brachial artery thrombosis; systemic anticoagulation.
. Complex regional pain syndrome; pain management.

Correct Answer & Explanation

. Acute compartment syndrome; emergency fasciotomy.

Explanation

The classic '5 Ps' (pain, pallor, pulselessness, paresthesias, paralysis) in the setting of a supracondylar humerus fracture are hallmark signs of acute compartment syndrome of the forearm. This is a surgical emergency requiring immediate fasciotomy to decompress the muscle compartments and restore blood flow. Left untreated, it quickly leads to irreversible muscle necrosis and nerve damage, resulting in Volkmann's ischemic contracture. The intervention directly addresses the critically elevated tissue pressure. The other options are either incorrect diagnoses or inappropriate treatments for this severe, time-sensitive condition.

Question 10044

Topic: 2. Trauma

What is the primary physiological consequence of excessive pressure exerted by a circular cast over a prolonged period, leading to potentially irreversible tissue damage?

. Increased venous return and edema.
. Compression of lymphatic vessels, causing lymphedema.
. Ischemia due to pressure exceeding capillary perfusion pressure.
. Stimulation of osteoclasts, leading to bone resorption.
. Localized allergic reaction to the casting material.

Correct Answer & Explanation

. Ischemia due to pressure exceeding capillary perfusion pressure.

Explanation

Excessive external pressure from a cast, especially circumferential, can exceed the capillary perfusion pressure (typically around 25-32 mmHg). When the external pressure is greater than the pressure inside the capillaries, blood flow to the underlying tissues is compromised, leading to ischemia. Prolonged ischemia results in cellular damage and necrosis, manifesting as pressure sores or, more severely, acute compartment syndrome if muscle compartments are involved. While lymphedema and venous issues can occur, the most devastating and direct consequence is ischemia.

Question 10045

Topic: 2. Trauma

Which type of fracture is most commonly associated with acute compartment syndrome of the lower leg, making prompt recognition of elevated compartment pressures crucial?

. Distal fibula fracture
. Isolated malleolar fracture
. Tibial shaft fracture
. Patella fracture
. Femoral shaft fracture

Correct Answer & Explanation

. Tibial shaft fracture

Explanation

Tibial shaft fractures, especially high-energy open or closed fractures, are the most common cause of acute compartment syndrome of the lower leg. The tibia's subcutaneous location and the potential for significant swelling and bleeding into the relatively unyielding compartments surrounding it predispose to dangerously elevated pressures. While any long bone fracture can theoretically lead to compartment syndrome, tibial shaft fractures have a particularly high association.

Question 10046

Topic: 2. Trauma

A 4-year-old child presents with a 'pulseless pink hand' following a supracondylar humerus fracture. Despite reduction, the radial pulse remains absent. What pressure-related assessment is critical in this scenario, even with a pink hand, to rule out evolving vascular compromise?

. Capillary refill time.
. Direct measurement of radial artery pressure.
. Doppler assessment of arterial flow.
. Venous pressure measurement in the forearm.
. Intracompartmental pressure measurement.

Correct Answer & Explanation

. Intracompartmental pressure measurement.

Explanation

In the 'pulseless pink hand' scenario, where pulses are absent but the hand is pink (indicating capillary perfusion), there's a risk of an incomplete or partial vascular injury that may still lead to compartment syndrome. While Doppler helps assess flow, the critical pressure-related assessment in this specific context is intracompartmental pressure measurement. Even with a pink hand, elevated compartment pressures can compromise muscle and nerve viability. A pulseless pink hand often signals arterial spasm or occlusion without immediate frank ischemia, but it's a red flag for developing compartment syndrome. Capillary refill and direct radial artery pressure are not as sensitive as compartment pressures in this specific 'pink pulseless' situation where collateral flow may be maintaining capillary perfusion while deeper compartment pressures rise.

Question 10047

Topic: 2. Trauma

A 28-year-old male sustains a crush injury to his forearm. He is complaining of severe pain and paresthesias. The nursing staff notes that his fingers are swollen and stiff. Which of the following is the most sensitive early clinical sign of acute compartment syndrome related to tissue pressure?

. Loss of distal pulses.
. Pallor of the skin.
. Pain out of proportion to the injury.
. Paralysis of the intrinsic muscles.
. Decreased sensation in the affected limb.

Correct Answer & Explanation

. Pain out of proportion to the injury.

Explanation

Pain out of proportion to the injury or to analgesia is consistently cited as the earliest and most reliable clinical sign of acute compartment syndrome. It reflects the increasing intramuscular pressure causing ischemia and nerve irritation. Loss of pulses, pallor, paralysis, and decreased sensation are often late signs, indicating significant and potentially irreversible tissue damage has already occurred. Early recognition of disproportionate pain is critical for prompt diagnosis and intervention.

Question 10048

Topic: 2. Trauma

What is the physiological rationale for frequently checking peripheral pulses distal to a fracture or surgical site, even if a tourniquet was not used?

. To monitor for signs of deep vein thrombosis.
. To assess for systemic blood pressure stability.
. To detect potential arterial injury or occlusion that compromises tissue perfusion pressure.
. To evaluate the effectiveness of pain medication.
. To identify nerve compression syndrome.

Correct Answer & Explanation

. To detect potential arterial injury or occlusion that compromises tissue perfusion pressure.

Explanation

Checking peripheral pulses is fundamental to assess arterial perfusion to the distal limb. A diminished or absent pulse can indicate an arterial injury (e.g., laceration, compression, or spasm) or an evolving compartment syndrome compromising the vascular supply. This directly relates to the concept of tissue perfusion pressure – if arterial inflow is compromised, perfusion pressure will drop, risking ischemia. While other issues might be present, the primary goal of pulse checks in this context is to detect acute arterial compromise.

Question 10049

Topic: 2. Trauma

When performing closed reduction and casting of a pediatric forearm fracture, what is a crucial technique to avoid excessive pressure and prevent compartment syndrome?

. Applying tight, circumferential padding directly over bony prominences.
. Ensuring the cast is molded snugly to the contours of the limb.
. Bivalving the cast proactively after application, even if symptoms are absent.
. Leaving adequate space for swelling, particularly at the elbow and wrist.
. Using waterproof cast material to prevent maceration.

Correct Answer & Explanation

. Leaving adequate space for swelling, particularly at the elbow and wrist.

Explanation

Leaving adequate space for swelling, especially at the proximal and distal ends of the cast and across joints like the elbow and wrist, is crucial. This is achieved by ensuring proper padding and avoiding excessive tightness during cast application. Tightly molded casts or casts that are too snug do not allow for the inevitable post-injury swelling, increasing the risk of compartment syndrome or pressure sores. Proactive bivalving is a more aggressive step, often done if a high suspicion of swelling exists or as a precaution. Avoiding direct tight padding over bony prominences is also important, but leaving space for swelling is more globally preventive.

Question 10050

Topic: 2. Trauma

What is the primary mechanism by which non-steroidal anti-inflammatory drugs (NSAIDs) can increase the risk of acute compartment syndrome in certain high-risk patients?

. They cause direct cellular toxicity to muscle tissue.
. They increase capillary permeability, leading to fluid extravasation and swelling.
. They inhibit platelet aggregation, increasing bleeding into a confined space.
. They reduce pain, masking the early symptoms of compartment syndrome.
. They cause direct vasoconstriction, reducing tissue perfusion.

Correct Answer & Explanation

. They inhibit platelet aggregation, increasing bleeding into a confined space.

Explanation

NSAIDs inhibit platelet aggregation, thereby increasing the risk of bleeding. In a closed compartment, increased bleeding (e.g., from a fracture) leads to a rapid rise in intracompartmental pressure, predisposing to or exacerbating acute compartment syndrome. While they do reduce pain, masking symptoms, their direct physiological effect on hemostasis is a more concerning mechanism in the context of compartment syndrome risk. They do not typically cause direct cellular toxicity, increase capillary permeability, or cause direct vasoconstriction relevant to this specific risk.

Question 10051

Topic: 2. Trauma

Which of the following conditions is characterized by acutely elevated intramuscular pressure in the medial compartment of the thigh, leading to pain and weakness, often requiring emergent fasciotomy?

. Iliotibial band syndrome.
. Adductor compartment syndrome.
. Hamstring strain.
. Femoral stress fracture.
. Meralgia paresthetica.

Correct Answer & Explanation

. Adductor compartment syndrome.

Explanation

Adductor compartment syndrome is an acute compartment syndrome affecting the medial (adductor) compartment of the thigh. It is a rare but serious condition that can occur after trauma, surgery, or prolonged external compression. Like other compartment syndromes, it involves acutely elevated intramuscular pressure that compromises tissue perfusion and can lead to muscle necrosis and nerve damage if not treated promptly with fasciotomy. The other conditions are not typically acute compartment syndromes of the medial thigh.

Question 10052

Topic: 2. Trauma

When managing a severe open tibia fracture with significant soft tissue injury, what is a key pressure-related principle of wound care and dressing application?

. Applying high-pressure bandages to control bleeding.
. Using occlusive dressings to prevent infection.
. Ensuring dressings are snug but not constrictive to avoid exacerbating local tissue pressure.
. Keeping the wound exposed to air to promote drying.
. Routinely packing the wound tightly with gauze.

Correct Answer & Explanation

. Ensuring dressings are snug but not constrictive to avoid exacerbating local tissue pressure.

Explanation

In severe open fractures with soft tissue injury, the management of dressings is crucial to avoid adding to local tissue pressure, which can compromise already damaged tissues and potentially contribute to compartment syndrome. Dressings should be applied snugly enough to provide coverage and absorb exudate but must not be constrictive. High-pressure bandages or tight packing can exacerbate ischemia. Occlusive dressings are not universally indicated for open wounds, and air exposure is generally discouraged to prevent contamination.

Question 10053

Topic: Pelvic & Acetabular Trauma

A patient sustains a pelvic ring injury. What is a critical initial 'pressure-related' maneuver to control hemorrhage associated with these injuries?

. Application of external pelvic compression (e.g., binder or sheet).
. Immediate surgical exploration and vessel ligation.
. Aggressive crystalloid fluid resuscitation.
. Insertion of a femoral traction pin.
. Transfusion of packed red blood cells.

Correct Answer & Explanation

. Application of external pelvic compression (e.g., binder or sheet).

Explanation

External pelvic compression, typically achieved with a pelvic binder or even a simple sheet wrapped tightly around the greater trochanters, is a critical initial maneuver in managing hemodynamically unstable pelvic ring injuries. By reducing the volume of the disrupted pelvic cavity, it helps to tamponade venous and arterial bleeding, thereby increasing pressure within the pelvic space and reducing hemorrhage. While fluid resuscitation and blood transfusion are also vital, they address theconsequencesof bleeding, whereas external compression directly helpscontrolthe bleeding source. Surgical exploration is reserved for ongoing instability despite compression. Femoral traction is for associated long bone fractures, not hemorrhage control.

Question 10054

Topic: 2. Trauma

A patient with a traumatic lower extremity injury is hypotensive (BP 70/40 mmHg). What is the priority 'pressure-related' goal for orthopedic management?

. To perform immediate open reduction and internal fixation of any fractures.
. To obtain intracompartmental pressure measurements of the injured limb.
. To restore systemic blood pressure to an adequate mean arterial pressure (MAP) to ensure limb and organ perfusion.
. To apply a tight compression bandage to the injured limb.
. To administer antibiotics prophylactically.

Correct Answer & Explanation

. To restore systemic blood pressure to an adequate mean arterial pressure (MAP) to ensure limb and organ perfusion.

Explanation

In a hypotensive trauma patient, the absolute priority is to restore systemic blood pressure to an adequate mean arterial pressure (MAP) (typically >65 mmHg) to ensure perfusion of vital organs and the injured limb. Without adequate systemic perfusion pressure, localized orthopedic interventions or measurements become secondary as the entire organism is at risk. Fixation is important but deferred until stabilization. Compartment pressures are not the initial priority in global hypoperfusion. Tight compression could worsen an already compromised limb. Antibiotics are important but not the immediate life-saving priority.

Question 10055

Topic: 2. Trauma

In the context of bone healing, what effect does excessive mechanical pressure (e.g., from an overly tight plate or external fixator frame) have at a fracture site?

. It promotes primary bone healing by direct contact osteogenesis.
. It accelerates callus formation and secondary healing.
. It can lead to avascular necrosis of bone fragments and delayed union or nonunion.
. It stimulates osteoblast activity and new bone formation.
. It reduces the risk of infection at the fracture site.

Correct Answer & Explanation

. It can lead to avascular necrosis of bone fragments and delayed union or nonunion.

Explanation

Excessive mechanical pressure at a fracture site, particularly if it compromises the local blood supply, can lead to avascular necrosis of bone fragments and subsequently result in delayed union or nonunion. While some compression (e.g., interfragmentary compression with a lag screw) is beneficial for primary bone healing, excessive or prolonged high-pressure compression (e.g., from an overly rigid fixation or external force) can impede vascularity and biological healing processes. It does not accelerate callus formation (which is for secondary healing), stimulate osteoblasts under ischemic conditions, or directly reduce infection risk.

Question 10056

Topic: 2. Trauma

Which of the following is considered a 'dynamic' pressure measurement used to assess for chronic exertional compartment syndrome (CECS)?

. Resting intracompartmental pressure.
. Compartment pressure measured immediately after exercise.
. Systolic blood pressure at rest.
. Diastolic blood pressure at rest.
. Static pressure of a cast on the limb.

Correct Answer & Explanation

. Compartment pressure measured immediately after exercise.

Explanation

The diagnosis of chronic exertional compartment syndrome (CECS) relies on dynamic pressure measurements taken after exercise. While resting pressures are usually normal in CECS, the pressure within the affected compartment typically rises significantly during exercise and remains elevated for several minutes post-exercise. Specific diagnostic criteria involve thresholds for pressures at 1 and 5 minutes post-exercise (e.g., >30 mmHg at 1 min, >20 mmHg at 5 min). Resting pressures, systemic blood pressures, and static cast pressures are not dynamic measurements for CECS.

Question 10057

Topic: 2. Trauma

A 28-year-old male sustains an open tibia fracture and large deep laceration to his thigh after a motorcycle accident. He is hypotensive with a BP of 85/45 mmHg. Estimated blood loss is 2 liters. What is the most appropriate immediate intravenous fluid for resuscitation?

. Dextrose 5% in Water (D5W)
. Lactated Ringer's solution
. 0.45% Normal Saline
. Albumin 5%
. Hydroxyethyl Starch

Correct Answer & Explanation

. Lactated Ringer's solution

Explanation

For initial fluid resuscitation in hypotensive trauma patients with significant blood loss, balanced crystalloid solutions like Lactated Ringer's (LR) are preferred. LR is isotonic and contains electrolytes (including lactate, which is metabolized to bicarbonate) that closely approximate plasma composition, reducing the risk of hyperchloremic metabolic acidosis seen with large volumes of 0.9% Normal Saline. D5W is hypotonic and rapidly distributes into the intracellular space, offering poor intravascular volume expansion. 0.45% NS is also hypotonic. Albumin and other colloids are typically reserved for specific situations and are not first-line for initial trauma resuscitation due to cost and some studies showing no mortality benefit over crystalloids, and some even showing harm (e.g., starch solutions). Current guidelines (ATLS) recommend balanced crystalloids.

Question 10058

Topic: 2. Trauma

A 78-year-old female with a hip fracture presents with confusion. Her serum sodium is 158 mEq/L, blood glucose is 110 mg/dL, and BUN/Cr are 40/1.8 mg/dL. She has poor skin turgor and dry mucous membranes. Her urine output has been noted to be low. What is the most appropriate initial fluid therapy to correct her hypernatremia?

. 0.9% Normal Saline at 200 mL/hr
. Dextrose 5% in water (D5W) at 100 mL/hr
. 0.45% Normal Saline at 150 mL/hr
. Dextrose 5% in 0.45% Normal Saline at 100 mL/hr
. Fluid restriction

Correct Answer & Explanation

. 0.45% Normal Saline at 150 mL/hr

Explanation

This patient has hypernatremia with signs of hypovolemia. The goal is to replace both free water and volume. 0.45% Normal Saline (half-normal saline) is an ideal choice as it provides free water (to correct the hypernatremia) while also providing some sodium (to expand the extracellular volume and address the hypovolemia) without lowering serum sodium too rapidly. D5W provides only free water and is often too rapid if used alone for hypovolemic hypernatremia, potentially leading to cerebral edema if correction is too fast. 0.9% Normal Saline would provide too much sodium, not effectively lowering the serum sodium. Fluid restriction would worsen the dehydration and hypernatremia.

Question 10059

Topic: 2. Trauma

A 65-year-old male with chronic alcohol abuse and liver cirrhosis presents for a complex ankle fracture repair. Pre-operatively, his serum sodium is 125 mEq/L. He has significant ascites and peripheral edema. What is the primary management strategy for his hyponatremia in the perioperative setting?

. Administer 3% hypertonic saline infusion
. Aggressive fluid restriction
. Administer intravenous albumin
. Increase oral sodium intake with salt tablets
. Administer loop diuretics

Correct Answer & Explanation

. Aggressive fluid restriction

Explanation

This patient has hypervolemic hyponatremia secondary to liver cirrhosis. The primary management is aggressive fluid restriction, as the hyponatremia is due to an excess of total body water relative to sodium. While albumin might be used to increase intravascular volume in specific circumstances (e.g., large volume paracentesis), it does not directly correct the dilutional hyponatremia. 3% hypertonic saline is reserved for severe, symptomatic hyponatremia. Increasing oral sodium intake would worsen his fluid retention and edema. Loop diuretics might be considered to reduce fluid overload but are secondary to fluid restriction and must be used cautiously to avoid worsening electrolyte imbalances.

Question 10060

Topic: 2. Trauma

A 40-year-old male undergoes a fasciotomy for compartment syndrome in his lower leg. Post-operatively, he receives intravenous fluids. On day 2, his serum sodium is 152 mEq/L, and he complains of thirst and weakness. His urine output is 250 mL/hr, and urine specific gravity is 1.005. What is the most appropriate management of his hypernatremia?

. Continue current intravenous fluids (assume 0.9% NS)
. Administer Desmopressin (DDAVP)
. Switch intravenous fluids to Dextrose 5% in Water (D5W)
. Administer 3% hypertonic saline
. Prescribe oral sodium chloride tablets

Correct Answer & Explanation

. Switch intravenous fluids to Dextrose 5% in Water (D5W)

Explanation

This patient has hypernatremia (152 mEq/L) with signs of dehydration (thirst, weakness). His high urine output (250 mL/hr) and low urine specific gravity (1.005, indicating dilute urine) suggest significant free water loss, potentially from diabetes insipidus (either central or nephrogenic) or osmotic diuresis, but more likely inadequate free water replacement with his current fluids. To correct hypernatremia due to free water deficit, D5W (which provides free water after glucose metabolism) is the most appropriate choice to gradually lower serum sodium. Continuing 0.9% NS would worsen hypernatremia. Desmopressin is for central diabetes insipidus, but the immediate need is free water. 3% hypertonic saline would worsen hypernatremia. Oral sodium tablets are contraindicated.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page