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2. Trauma MCQs

Practice Set 22 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 421

Topic: 2. Trauma

A 28-year-old female sustains a closed midshaft femur fracture. 48 hours postoperatively, she develops confusion, a petechial rash over her axillae, and hypoxemia. What is the most likely diagnosis?

. Deep vein thrombosis
. Pulmonary embolism
. Fat embolism syndrome
. Sepsis
. Acute respiratory distress syndrome

Correct Answer & Explanation

. Fat embolism syndrome

Explanation

The classic triad of Fat Embolism Syndrome (FES) includes respiratory distress, neurologic abnormalities, and a petechial rash. It typically presents 24 to 72 hours after long bone trauma.

Question 422

Topic: 2. Trauma

A 24-year-old male sustains a closed femoral shaft fracture. Thirty-six hours later, he develops acute confusion, tachypnea, and hypoxemia. Which of the following is considered a major criteria for diagnosing his most likely condition according to Gurd's criteria?

. Tachycardia
. Fever
. Petechial rash
. Jaundice
. Retinal changes

Correct Answer & Explanation

. Petechial rash

Explanation

This patient has Fat Embolism Syndrome (FES). According to Gurd's criteria, the major criteria include petechial rash, respiratory insufficiency, and cerebral involvement.

Question 423

Topic: 2. Trauma

A polytrauma patient develops acute respiratory distress syndrome (ARDS) following bilateral femur fractures and massive fluid resuscitation. What is the primary pathophysiological mechanism underlying the pulmonary edema seen in ARDS?

. Increased pulmonary capillary hydrostatic pressure
. Decreased plasma oncotic pressure
. Increased alveolar-capillary permeability
. Surfactant overproduction
. Lymphatic obstruction

Correct Answer & Explanation

. Increased alveolar-capillary permeability

Explanation

ARDS is characterized by non-cardiogenic pulmonary edema resulting from diffuse inflammatory injury to the alveolar-capillary membrane, which significantly increases its permeability.

Question 424

Topic: 2. Trauma

A 32-year-old male sustains a closed tibial shaft fracture. Twelve hours later, he complains of severe leg pain that is unrelieved by intravenous opioids. Passive stretch of the toes dramatically exacerbates the pain. Which of the following is the most reliable early clinical indicator of acute compartment syndrome?

. Loss of distal palpable pulses
. Capillary refill time greater than 3 seconds
. Pain out of proportion to injury and with passive stretch
. Paresthesia in the first web space
. Motor paralysis of the extensor hallucis longus

Correct Answer & Explanation

. Pain out of proportion to injury and with passive stretch

Explanation

Pain out of proportion to the injury and pain elicited by passive stretch of the muscles in the involved compartment are the most reliable and earliest clinical signs of acute compartment syndrome. Pulselessness is a very late and unreliable sign.

Question 425

Topic: Pelvic & Acetabular Trauma
In a hemodynamically unstable patient with an anterior-posterior compression (APC) type III pelvic ring injury, what is the primary biomechanical rationale for applying a circumferential pelvic binder?
. To anatomically reduce the fracture of the sacrum
. To decrease pelvic volume to promote tamponade of venous bleeding
. To directly compress the internal iliac artery against the pelvic brim
. To immobilize the hip joints to prevent sciatic nerve injury
. To align the pubic symphysis to prevent urethral injury

Correct Answer & Explanation

. To decrease pelvic volume to promote tamponade of venous bleeding

Explanation

A pelvic binder internally rotates the hemipelves, effectively reducing the intrapelvic volume. This promotes the tamponade effect on bleeding cancellous bone surfaces and the presacral venous plexus, which are the most common sources of hemorrhage.

Question 426

Topic: 2. Trauma

A 28-year-old male sustains a spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). On examination, he demonstrates an inability to extend his wrist or fingers. At what specific anatomical location is the involved nerve most vulnerable to entrapment or injury in this specific fracture pattern?

. As it passes through the quadrilateral space
. At the spiral groove of the humerus
. As it pierces the lateral intermuscular septum
. At the level of the arcade of Frohse
. As it passes between the two heads of the supinator

Correct Answer & Explanation

. As it pierces the lateral intermuscular septum

Explanation

In a Holstein-Lewis fracture (distal third spiral humerus fracture), the radial nerve is tethered and particularly vulnerable to injury or entrapment as it pierces the lateral intermuscular septum to pass from the posterior to the anterior compartment.

Question 427

Topic: 2. Trauma

A 24-year-old woman is brought to the Emergency Department with thorax injuries after a road traffic accident. Her chest X-ray shows multiple rib fractures and a right-sided shadow suggestive of a haemothorax. Her O2 saturation is compromised at 91% on 10 litres of oxygen. What is the next step in her management?

. Blood transfusion
. Computed tomography (CT) of the thorax
. Intercostal drain insertion
. Intubation and ventilation
. Surgical referral for thoracotomy

Correct Answer & Explanation

. Intercostal drain insertion

Explanation

Correct Answer: C- Intercostal drain insertion Explanation Intercostal drain insertion A haemothorax is the result of bleeding into the pleural space, and is arbitrarily diagnosed on the basis of having a haematocrit that is more than half that of peripheral blood. This distinguishes it from a blood-stained effusion, which can be associated with a number of different pathological processes. The vast majority of haemothoraces are associated with penetrating or non- penetrating trauma, including iatrogenic procedures such as central venous catheterisation. Bleeding usually results from parenchymal laceration or damage to intercostal vessels. A pneumothorax is present in a high proportion of patients. The treatment of choice is to insert a large intercostal drain (28–32 F), allowing evacuation of blood and reducing the incidence of a subsequent fibrothorax. If this reveals continued bleeding, a thoracotomy might be required. Surgery is not indicated simply to remove any residual blood clots because there is spontaneous lysis with no residual damage in the majority of patients. Blood transfusion Blood transfusion is incorrect. A transfusion may or may not be required and would depend on the degree of blood loss and the patient’s hemoglobin, neither of which is revealed here. However, the priority on this case is to improve this lady’s oxygenation urgently by draining off the haemothorax. Computed tomography (CT) of the thorax Computed tomography (CT) of the thorax is incorrect. The priority here is to urgently improve this lady’s oxygenation. The diagnosis is clear here and requires urgent intervention to improve oxygenation. A CT thorax can be performed following stabilisation of the patient, if needs be. Intubation and ventilation Intubation and ventilation is incorrect. It would be appropriate to drain the hameothorax and reassess this lady’s oxygenation and clinical status, which is likely to improve significantly following drain insertion, before considering intubation and ventilation – which would worsen any untreated pneumothorax that may be present here. Surgical referral for thoracotomy Surgical referral for thoracotomy is incorrect. This may well be required, but the first line of intervention should be insertion of a chest drain.

Question 428

Topic: 2. Trauma

A 21-year-old medical student presents with confusion and dyspnoea 24 hours after fracturing his left femur in a ski competition. Which one of the following skin lesions would you expect to see on physical examination?

. Multiple petechiae in both axillae and skin folds of the upper body
. Multiple vesicular lesions on the upper back
. Palpable purpura on the buttock only
. Target lesions on the chest
. Tender red nodules on the shin

Correct Answer & Explanation

. Multiple petechiae in both axillae and skin folds of the upper body

Explanation

Correct Answer: A- Multiple petechiae in both axillae and skin folds of the upper body Explanation Multiple petechiae in both axillae and skin folds of the upper body This is a ‘know it or you don’t’ sort of question. The appearance of showers of petechiae over the axillae or upper half of the body is characteristic of fat embolism syndrome, which occurs in patients with a history of recent traumatic fracture. Multiple vesicular lesions on the upper back Multiple vesicular lesions on the upper back is incorrect. This is not an expected finding of fat embolism. Palpable purpura on the buttock only Palpable purpura on the buttock only is incorrect. This is not an expected finding of fat embolism. Target lesions on the chest Target lesions on the chest is incorrect. This is not an expected finding of fat embolism. Tender red nodules on the shin Tender red nodules on the shin is incorrect. This is not an expected finding of fat embolism.

Question 429

Topic: 2. Trauma
A 30-year-old polytrauma patient sustains an anteroposterior compression (APC) type III pelvic ring injury. Despite the application of a pelvic binder, 2 liters of crystalloid, and 2 units of packed red blood cells, he remains hypotensive. He is currently in the operating room undergoing an emergency laparotomy for an associated bowel perforation. What is the most appropriate next step in managing his pelvic hemorrhage?
. Application of an external fixator
. Pre-peritoneal pelvic packing
. Recombinant factor VII administration
. Embolization of the internal iliac artery
. Bilateral internal iliac artery ligation

Correct Answer & Explanation

. Pre-peritoneal pelvic packing

Explanation

In a hemodynamically unstable patient with a pelvic ring injury who is already in the operating room for laparotomy, pre-peritoneal pelvic packing is the most rapid and effective direct intervention for venous bleeding. Angiography is indicated if bleeding persists post-packing, typically targeting arterial sources.

Question 430

Topic: 2. Trauma

A 35-year-old man sustains a closed high-energy tibial shaft fracture. Hours later, he develops excruciating pain out of proportion to the injury, pain with passive toe stretch, and a tense compartment. In borderline cases requiring intra-compartmental pressure monitoring, which delta pressure threshold universally dictates the need for a fasciotomy?

. < 10 mmHg
. < 20 mmHg
. < 30 mmHg
. < 40 mmHg
. < 50 mmHg

Correct Answer & Explanation

. < 30 mmHg

Explanation

Acute compartment syndrome is primarily a clinical diagnosis, but tissue pressure monitoring is useful in equivocal cases or obtunded patients. A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the accepted threshold for performing an emergency fasciotomy.

Question 431

Topic: Pelvic & Acetabular Trauma
A 45-year-old man is brought to the trauma bay after a high-speed motorcycle collision. He is hypotensive with a blood pressure of 80/50 mmHg. An AP pelvis radiograph reveals an anteroposterior compression type III (APC III) pelvic ring injury. A pelvic binder is applied, and a FAST scan is negative. His blood pressure remains 75/40 mmHg after 2 liters of crystalloid. What is the most appropriate next step in management?
. Bilateral lower extremity traction
. Immediate exploratory laparotomy
. Preperitoneal pelvic packing and/or angiography
. Placement of an external fixator in the emergency department
. Administration of hypertonic saline

Correct Answer & Explanation

. Preperitoneal pelvic packing and/or angiography

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST scan, the source of bleeding is likely pelvic. After applying a pelvic binder, the next most appropriate step is preperitoneal pelvic packing or pelvic angiography to control venous or arterial hemorrhage.

Question 432

Topic: 2. Trauma

A 28-year-old man sustains a closed diaphyseal tibia fracture. Twelve hours post-admission, he develops severe, unrelenting leg pain out of proportion to the injury, significantly worsened by passive stretch of the toes. Which of the following compartment pressure measurements is the most accepted threshold for performing an emergency four-compartment fasciotomy?

. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 25 mmHg
. Delta pressure (Diastolic BP - Compartment Pressure) < 30 mmHg
. Delta pressure (Systolic BP - Compartment Pressure) < 40 mmHg
. Delta pressure (Mean Arterial Pressure - Compartment Pressure) < 20 mmHg

Correct Answer & Explanation

. Delta pressure (Diastolic BP - Compartment Pressure) < 30 mmHg

Explanation

A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the most reliable objective threshold for diagnosing acute compartment syndrome. Relying on absolute pressures alone can lead to unnecessary fasciotomies or missed diagnoses depending on systemic blood pressure.

Question 433

Topic: Pelvic & Acetabular Trauma

A 35-year-old male is brought to the trauma bay following a high-speed motorcycle collision. He is hemodynamically unstable with a suspected pelvic ring disruption. Where is the most appropriate anatomical level to apply a pelvic circumferential compression device (pelvic binder)?

. At the level of the iliac crests
. At the level of the anterior superior iliac spines
. At the level of the greater trochanters
. Just proximal to the pubic symphysis
. At the level of the lower lumbar spine

Correct Answer & Explanation

. At the level of the greater trochanters

Explanation

Pelvic binders should be placed at the level of the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests is incorrect and can exacerbate rotational deformities.

Question 434

Topic: 2. Trauma

A 28-year-old male presents with a closed tibial shaft fracture following a skiing accident. Six hours post-admission, he complains of worsening leg pain that is not relieved by intravenous opioids. Which of the following is the most sensitive early clinical sign of acute compartment syndrome?

. Absence of distal pulses
. Paresthesia in the first web space
. Pain with passive stretch of the toes
. Palpably tense calf compartments
. Motor paralysis of the deep posterior compartment

Correct Answer & Explanation

. Pain with passive stretch of the toes

Explanation

Pain with passive stretch of the muscles within the affected compartment is typically the most sensitive and earliest clinical sign of acute compartment syndrome. Pulselessness and paralysis are late, irreversible signs.

Question 435

Topic: 2. Trauma
A 22-year-old male sustains a vertically oriented, displaced femoral neck fracture (Pauwels type III). Open reduction and internal fixation are planned. Which of the following fixation constructs provides superior biomechanical stability for this high-shear fracture pattern?
. Three parallel cancellous screws
. Sliding hip screw with a derotation screw
. Smooth Steinmann pins
. Tension band wiring
. Isolated anterior buttress plate

Correct Answer & Explanation

. Sliding hip screw with a derotation screw

Explanation

Pauwels type III (vertical) femoral neck fractures have high shear forces and a high rate of failure with parallel screws alone. A sliding hip screw (with or without a derotation screw) provides a fixed-angle construct that offers superior biomechanical stability.

Question 436

Topic: 2. Trauma
A 45-year-old male presents with an open segmental fracture of his right tibia with a 12 cm soft tissue defect and exposed stripped bone, but intact distal pulses. After initial stabilization and antibiotics, he undergoes debridement and external fixation. According to the Gustilo-Anderson classification, what is the optimal timing for soft tissue coverage?
. Primary closure during the index procedure
. Split-thickness skin grafting at 48 hours
. Flap coverage within 5 to 7 days
. Delayed primary closure at 3 weeks
. Healing by secondary intention

Correct Answer & Explanation

. Flap coverage within 5 to 7 days

Explanation

This is a Gustilo-Anderson IIIB fracture requiring flap coverage. Evidence suggests that early soft tissue coverage with a local or free flap within 5 to 7 days minimizes the risk of deep infection and osteomyelitis.

Question 437

Topic: 2. Trauma

A 19-year-old male sustains a scaphoid proximal pole fracture. Which of the following anatomical characteristics of the scaphoid is most responsible for the high rate of avascular necrosis and nonunion seen in this specific fracture pattern?

. Intra-articular location limiting callus formation
. Lack of ligamentous attachments to the proximal pole
. Retrograde blood supply via branches of the radial artery
. High shear forces across the radiocarpal joint
. Presence of a watershed line on the volar surface

Correct Answer & Explanation

. Retrograde blood supply via branches of the radial artery

Explanation

The primary blood supply to the scaphoid enters distally from branches of the radial artery and flows retrograde to the proximal pole. Proximal pole fractures disrupt this supply, leading to a high risk of avascular necrosis.

Question 438

Topic: 2. Trauma

A 45-year-old man sustains a Schatzker type II lateral tibial plateau fracture. Which of the following is the most widely accepted indication for operative intervention in this specific injury pattern?

. Joint depression greater than 2 mm
. Valgus instability greater than 10 degrees in nearly full extension
. Widening of the tibial plateau greater than 1 mm
. Presence of a moderate hemarthrosis
. Associated proximal fibular fracture

Correct Answer & Explanation

. Valgus instability greater than 10 degrees in nearly full extension

Explanation

Operative indications for a lateral tibial plateau fracture include valgus instability >10 degrees in near-full extension, articular step-off >3-5 mm, or an open fracture.

Question 439

Topic: Pelvic & Acetabular Trauma
A 35-year-old man is brought in after a severe motorcycle crash. Pelvic radiographs demonstrate an anteroposterior compression (APC) type III pelvic ring injury. Which of the following ligamentous complexes is disrupted in this injury pattern but remains intact in an APC type II injury?
. Anterior sacroiliac ligament
. Sacrospinous ligament
. Sacrotuberous ligament
. Posterior sacroiliac ligament
. Iliolumbar ligament

Correct Answer & Explanation

. Posterior sacroiliac ligament

Explanation

APC III injuries involve complete disruption of the pelvic ring, including both anterior and posterior sacroiliac ligaments. APC II injuries spare the strong posterior SI ligaments.

Question 440

Topic: 2. Trauma

In an adult patient with a displaced intracapsular femoral neck fracture, which artery provides the predominant blood supply to the femoral head and is at greatest risk of catastrophic disruption?

. Artery of the ligamentum teres
. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Inferior gluteal artery
. Superior gluteal artery

Correct Answer & Explanation

. Medial femoral circumflex artery

Explanation

The lateral epiphyseal branches of the medial femoral circumflex artery provide the main blood supply to the adult femoral head and are highly vulnerable to tearing in displaced neck fractures.

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