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2. Trauma MCQs

Practice Set 25 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 481

Topic: 2. Trauma

A 24-year-old male sustains a closed comminuted diaphyseal femur fracture. 36 hours post-admission, he develops progressive hypoxia, a petechial rash over his axillae, and confusion. Which of the following is the primary pathophysiological mechanism responsible for his respiratory compromise?

. Pulmonary infarction from macro-thrombi
. Endothelial damage via circulating free fatty acids
. Direct alveolar compression from pleural effusions
. Cardiogenic pulmonary edema from myocardial contusion
. Bronchospasm secondary to systemic inflammatory response

Correct Answer & Explanation

. Endothelial damage via circulating free fatty acids

Explanation

Fat embolism syndrome (FES) is characterized by hypoxia, petechiae, and neurological decline. The primary pathogenesis involves circulating free fatty acids causing toxic endothelial damage, leading to an ARDS-like pulmonary compromise.

Question 482

Topic: 2. Trauma

A 24-year-old male sustains a closed femoral shaft fracture in a motor vehicle collision. Twenty-four hours later, he develops unexplained tachycardia, a petechial rash over his anterior axillary folds, and sudden confusion. Arterial blood gas shows a PaO2 of 55 mmHg on room air. According to Gurd and Wilson's criteria, which of the following clinical features in this patient is considered a major criterion for the most likely diagnosis?

. Tachycardia greater than 120 beats per minute
. Petechial rash
. Pyrexia greater than 39.0 degrees Celsius
. Unexplained drop in hematocrit
. Oliguria

Correct Answer & Explanation

. Petechial rash

Explanation

The patient is presenting with Fat Embolism Syndrome. Gurd and Wilson's major criteria include a petechial rash, respiratory insufficiency, and cerebral involvement. Tachycardia, pyrexia, and a drop in hematocrit are considered minor criteria.

Question 483

Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the emergency department after a high-speed motorcycle collision. His blood pressure is 70/40 mmHg and heart rate is 135 bpm. A pelvic radiograph shows an anteroposterior compression type III (APC-III) pelvic ring injury. A pelvic binder is applied correctly, but he remains hemodynamically unstable despite aggressive blood product resuscitation. A FAST scan is negative. What is the most appropriate next step in his management?
. Application of an external fixator
. Urgent exploratory laparotomy
. Retrograde urethrogram to rule out urethral injury
. Preperitoneal pelvic packing or pelvic angiography
. Immediate open reduction and internal fixation of the symphysis pubis

Correct Answer & Explanation

. Preperitoneal pelvic packing or pelvic angiography

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST scan, the bleeding is typically retroperitoneal from the presacral venous plexus or internal iliac branches. Preperitoneal pelvic packing or angioembolization is the standard life-saving next step after binder application.

Question 484

Topic: 2. Trauma

A 22-year-old male falls onto an outstretched hand and presents with swelling and severe anatomical snuffbox tenderness. Radiographs confirm a displaced fracture of the proximal pole of the scaphoid. Why is this specific fracture pattern at a significantly high risk for nonunion and avascular necrosis?

. Lack of stabilizing ligamentous attachments to the proximal pole
. Retrograde blood supply via the dorsal carpal branch of the radial artery
. Poor baseline bone mineral density in the proximal carpal row
. Extensive cartilaginous covering that prevents adequate fracture callus formation
. High concentration of osteoclasts in the proximal pole of the scaphoid

Correct Answer & Explanation

. Retrograde blood supply via the dorsal carpal branch of the radial artery

Explanation

The scaphoid receives its primary blood supply in a retrograde fashion from the dorsal carpal branch of the radial artery, which enters the bone distally. Proximal pole fractures disrupt this intraosseous vascular supply, leading to high rates of ischemia, AVN, and nonunion.

Question 485

Topic: 2. Trauma

A 25-year-old male is admitted with a closed diaphyseal femur fracture. Thirty-six hours after admission, he becomes agitated and confused. Examination reveals a petechial rash over his axillae and conjunctivae. His oxygen saturation is 86% on room air. What is the most appropriate initial management?

. Immediate open reduction and internal fixation of the femur
. Administration of high-dose intravenous corticosteroids
. Administration of low-molecular-weight heparin
. Supportive care with supplemental oxygen and mechanical ventilation if necessary
. Placement of an inferior vena cava filter

Correct Answer & Explanation

. Supportive care with supplemental oxygen and mechanical ventilation if necessary

Explanation

This patient presents with classic signs of fat embolism syndrome (hypoxia, confusion, petechial rash) following a long bone fracture. The mainstay of treatment is supportive care, primarily focusing on maintaining adequate oxygenation and hemodynamics.

Question 486

Topic: 2. Trauma

A 28-year-old male polytrauma patient presents with bilateral femur fractures, a pulmonary contusion, and a closed head injury. His serum lactate is 4.5 mmol/L, base deficit is -8, and pH is 7.21. Which of the following is the most appropriate orthopedic management strategy?

. Early total care with reamed intramedullary nailing of both femurs
. Damage control orthopedics with external fixation of both femurs
. Non-operative management with skeletal traction until discharge
. Open reduction and internal fixation with plates and screws
. Immediate amputation of the more severely injured limb

Correct Answer & Explanation

. Damage control orthopedics with external fixation of both femurs

Explanation

This patient is physiologically unstable as indicated by elevated lactate, significant base deficit, and acidosis, making him a poor candidate for early total care. Damage control orthopedics (DCO) using temporary external fixation minimizes the systemic inflammatory response and secondary hits.

Question 487

Topic: 2. Trauma

A 34-year-old male sustains a closed spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). On initial presentation, his radial nerve function is intact. Following a closed reduction and application of a coaptation splint, the patient is unable to extend his wrist or fingers. What is the most appropriate next step in management?

. Immediate surgical exploration and nerve release
. Observation and repeat examination in 2 weeks
. Electromyography (EMG) and nerve conduction studies
. Application of a functional fracture brace
. Administration of intravenous corticosteroids

Correct Answer & Explanation

. Immediate surgical exploration and nerve release

Explanation

A secondary radial nerve palsy that develops immediately after closed reduction of a humeral shaft fracture strongly suggests nerve entrapment within the fracture site. This is an absolute indication for immediate surgical exploration.

Question 488

Topic: 2. Trauma

A 45-year-old male presents with a closed tibial plateau fracture. He complains of pain out of proportion to his injury that is exacerbated by passive stretch of his toes. Compartment pressure monitoring reveals an anterior compartment pressure of 35 mmHg. His diastolic blood pressure is 60 mmHg. What is the most appropriate action?

. Elevate the leg above the level of the heart
. Administer intravenous analgesics and observe
. Perform a four-compartment fasciotomy of the leg
. Apply a long leg cast
. Measure venous doppler pressures

Correct Answer & Explanation

. Perform a four-compartment fasciotomy of the leg

Explanation

The diagnosis of acute compartment syndrome is supported by a delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg. In this case, the delta pressure is 25 mmHg, which is a strong indication for an urgent four-compartment fasciotomy.

Question 489

Topic: 2. Trauma
A 40-year-old male is brought to the trauma bay after a high-speed motorcycle collision. His blood pressure is 80/50 mmHg. Pelvic radiographs reveal an "open book" (APC-III) pelvic ring disruption. A pelvic binder is applied, and he receives 2 units of packed red blood cells, but his blood pressure remains 85/55 mmHg. What is the next most appropriate step?
. Immediate exploratory laparotomy
. Retrograde urethrogram
. Pelvic angiography with embolization or pre-peritoneal packing
. Application of an external fixator
. Observation in the intensive care unit

Correct Answer & Explanation

. Pelvic angiography with embolization or pre-peritoneal packing

Explanation

In a hemodynamically unstable patient with an APC-III pelvic fracture despite mechanical stabilization (binder) and initial volume resuscitation, the primary source of bleeding is likely venous or arterial from the presacral plexus. Pelvic packing or angiography with embolization is the standard next step to achieve hemostasis.

Question 490

Topic: 2. Trauma

A 48-year-old woman presents with a pleural effusion. You perform a diagnostic pleural aspiration. Which of the following is true regarding the results that you might receive from the laboratory?

. An eosinophilia makes malignancy less likely
. Heavy bloodstaining effectively excludes pulmonary embolic disease
. High glucose levels occur in rheumatoid arthritis
. Low levels of salivary amylase suggest oesophageal rupture
. The presence of antinuclear factor is virtually diagnostic of scleroderma

Correct Answer & Explanation

. An eosinophilia makes malignancy less likely

Explanation

Correct Answer: A- An eosinophilia makes malignancy less likely Explanation An eosinophilia makes malignancy less likely Pleural fluid eosinophilia (> 10%) makes malignancy and tuberculosis (TB) less likely, and suggests air in the pleural cavity. Heavy bloodstaining effectively excludes pulmonary embolic disease Heavy bloodstaining effectively excludes pulmonary embolic disease is incorrect. Heavily bloodstained fluid in the absence of trauma suggests pulmonary infarction or malignancy. High glucose levels occur in rheumatoid arthritis High glucose levels occur in rheumatoid arthritis is incorrect. Low glucose levels occur in rheumatoid arthritis, TB, empyema and malignancy. Low levels of salivary amylase suggest oesophageal rupture Low levels of salivary amylase suggest oesophageal rupture is incorrect. High levels of salivary amylase suggest oesophageal rupture. The presence of antinuclear factor is virtually diagnostic of scleroderma The presence of antinuclear factor is virtually diagnostic of scleroderma is incorrect. The presence of antinuclear factor is virtually diagnostic of systemic lupus erythematosus (SLE), not scleroderma.

Question 491

Topic: 2. Trauma

In which of the following emergency medical presentations is non-invasive ventilation an established first choice therapy in the presence of respiratory acidosis?

. Acute asthma
. Acute exacerbation of chronic obstructive pulmonary disease with respiratory acidosis
. Adult respiratory distress syndrome (ARDS)
. Pulmonary oedema with hypertension
. Tension pneumothorax

Correct Answer & Explanation

. Acute exacerbation of chronic obstructive pulmonary disease with respiratory acidosis

Explanation

Correct Answer: B- Acute exacerbation of chronic obstructive pulmonary disease with respiratory acidosis Explanation Acute exacerbation of chronic obstructive pulmonary disease with respiratory acidosis Non-invasive ventilation (NIV) is currently being evaluated in a number of emergency situations. The best evidence relates to exacerbations of chronic obstructive pulmonary disease. In particular, this type of therapy is effective in patients with decompensated type II respiratory failure. Physiological responses (heart rate, respiratory rate and arterial blood gases) improve more quickly with NIV in these patients compared with standard treatment. Intubation is also less frequently required. Acute asthma Acute asthma is incorrect. The correct management for acute asthma with respiratory acidosis is oxygen, steroids, nebulised bronchodilators, intravenous magnesium alongside urgent critical care/anaesthetic for consideration of intubation and invasive ventilation. Adult respiratory distress syndrome (ARDS) Adult respiratory distress syndrome (ARDS) is incorrect. ARDS with respiratory acidosis is best managed with invasive ventilation using low tidal volumes (6 mL/kg based upon ideal body weight). Pulmonary oedema with hypertension Pulmonary oedema with hypertension is incorrect. NIV is part of a range of therapies for pulmonary oedema, but more usually where pulmonary oedema co-exists with hypertension, diuretics and measures to control blood pressure are normally attempted first. Tension pneumothorax Tension pneumothorax is incorrect. The correct first choice treatment for tension pneumothorax is immediate needle decompression followed by intercostal drain insertion.

Question 492

Topic: 2. Trauma

A 24-year-old male sustains a closed femoral shaft fracture. Forty-eight hours later, he develops confusion, petechiae over the axilla, and a PaO2 of 55 mmHg. What is the primary pathophysiological mechanism responsible for his hypoxemia?

. Hypoventilation secondary to undiagnosed traumatic brain injury
. Right-to-left shunting due to ARDS-like endothelial damage
. Complete pulmonary artery occlusion by a large macroscopic fat globule
. Severe bronchoconstriction from systemic histamine release
. Alveolar hypoventilation from narcotic overdose

Correct Answer & Explanation

. Right-to-left shunting due to ARDS-like endothelial damage

Explanation

The hypoxemia in fat embolism syndrome is primarily due to a secondary inflammatory cascade causing endothelial damage, acute respiratory distress syndrome (ARDS), and resulting V/Q mismatch with right-to-left shunting. It is not merely a mechanical occlusion by fat globules.

Question 493

Topic: 2. Trauma

Primary bone healing (osteonal reconstruction) is desired in the rigid fixation of articular fractures. Which biomechanical environment is absolutely required for primary bone healing to occur?

. Relative stability with extensive micromotion
. Absolute stability with intact intramedullary blood supply
. Callus formation under dynamic compression
. Absolute stability with interfragmentary strain less than 2 percent
. Interfragmentary strain between 2 and 10 percent

Correct Answer & Explanation

. Absolute stability with interfragmentary strain less than 2 percent

Explanation

Primary bone healing occurs via cutting cones and requires absolute stability with an interfragmentary strain of less than 2%. Higher strains lead to secondary bone healing with callus formation or nonunion.

Question 494

Topic: 2. Trauma

A meta-analysis investigates the association between smoking and tibial nonunion. The pooled Relative Risk (RR) is reported as 2.8, with a 95% Confidence Interval (CI) of [0.9, 4.7]. What is the correct interpretation of these statistical findings?

. Smoking significantly increases the risk of nonunion.
. The result is statistically significant because the RR is greater than 1.0.
. The result is not statistically significant because the confidence interval crosses 1.0.
. Smoking reduces the risk of nonunion.
. The sample size was too large, causing a wide confidence interval.

Correct Answer & Explanation

. The result is not statistically significant because the confidence interval crosses 1.0.

Explanation

For ratio measures such as Relative Risk or Odds Ratio, a 95% confidence interval that includes 1.0 indicates that there is no statistically significant difference between the groups at the 0.05 alpha level.

Question 495

Topic: 2. Trauma

A 40-year-old patient is evaluated for an unhealed tibial shaft fracture 8 months after cast immobilization. The surgeon plans an operation. To ensure primary (osteonal) bone healing without callus formation, what biomechanical environment must the surgical construct provide?

. Absolute stability with interfragmentary compression
. Relative stability with a bridge plate
. Relative stability with an unreamed intramedullary nail
. Dynamic axial loading via an external fixator
. Micro-motion between 2% and 10% gap strain

Correct Answer & Explanation

. Absolute stability with interfragmentary compression

Explanation

Primary (osteonal) bone healing occurs without callus formation and requires absolute stability (gap strain <2%) and intimate contact, typically achieved through lag screw fixation and compression plating.

Question 496

Topic: 2. Trauma

A 25-year-old man with bilateral femur fractures develops sudden confusion, severe hypoxia, and a non-blanching rash on his chest 36 hours post-injury. According to Gurd's diagnostic criteria, which of the following is considered a major criterion for this condition?

. Tachycardia > 120 bpm
. Fever > 39°C
. Petechial rash
. Jaundice
. Unexplained thrombocytopenia

Correct Answer & Explanation

. Petechial rash

Explanation

Gurd's major criteria for fat embolism syndrome include petechial rash, respiratory insufficiency, and cerebral involvement (confusion/coma). Tachycardia, fever, and thrombocytopenia are considered minor criteria.

Question 497

Topic: 2. Trauma

A 45-year-old woman presents with sudden onset pleuritic chest pain and dyspnea 2 weeks after an ORIF of a tibial plateau fracture. Her ECG shows an S1Q3T3 pattern. What is the next best step for definitive confirmation of her suspected diagnosis?

. Serum D-dimer assay
. CT pulmonary angiography (CTPA)
. Ventilation-perfusion (V/Q) scan
. Transthoracic echocardiogram
. Lower limb duplex ultrasound

Correct Answer & Explanation

. CT pulmonary angiography (CTPA)

Explanation

The clinical presentation and classic ECG findings suggest a pulmonary embolism. CT pulmonary angiography (CTPA) is the gold standard imaging modality for definitive diagnosis in a hemodynamically stable patient.

Question 498

Topic: 2. Trauma

A 28-year-old man is post-operative day 1 following intramedullary nailing of a closed tibia fracture. His temperature is 38.2°C. His lungs are clear, the wound is clean, and there is no excessive calf swelling. What is the most likely cause of his fever?

. Deep vein thrombosis
. Pulmonary embolism
. Surgical site infection
. Normal physiological inflammatory response to tissue trauma
. Catheter-associated urinary tract infection

Correct Answer & Explanation

. Normal physiological inflammatory response to tissue trauma

Explanation

Low-grade fever within the first 24-48 hours after major orthopedic trauma or surgery is extremely common and usually represents a normal cytokine-mediated inflammatory response to tissue injury. Early post-operative fever is rarely due to surgical site infection.

Question 499

Topic: 2. Trauma
A 35-year-old man sustains an unstable pelvic ring fracture in a high-speed motor vehicle collision. On arrival, his BP is 85/50 mmHg, HR is 135 bpm, and his urine output is negligible. Into which class of hemorrhagic shock does this patient fall, and what is his estimated blood volume loss?
. Class I, < 750 mL
. Class II, 750-1500 mL
. Class III, 1500-2000 mL
. Class IV, > 2000 mL
. Class V, > 3000 mL

Correct Answer & Explanation

. Class III, 1500-2000 mL

Explanation

The patient is in Class III hemorrhagic shock, characterized by a drop in measurable blood pressure, tachycardia (120-140 bpm), and decreased urine output. This correlates with a 30-40% loss of blood volume, or roughly 1500-2000 mL in an average adult.

Question 500

Topic: 2. Trauma

A 22-year-old man with an acute, closed tibia fracture develops disproportionate leg pain, swelling, and paresthesia. Intracompartmental pressure is measured. Which of the following values definitively confirms an acute compartment syndrome necessitating emergency 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) < 30 mmHg
. Delta pressure (Mean Arterial Pressure - Compartment Pressure) < 40 mmHg

Correct Answer & Explanation

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

Explanation

Acute compartment syndrome is definitively diagnosed when the delta pressure (diastolic blood pressure minus intracompartmental pressure) falls below 30 mmHg. Relying on absolute pressure alone can lead to overtreatment or missed diagnosis depending on the patient's systemic blood pressure.

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