MCQs on Thromboembolism

MCQ Bank Hematology Module

Written by Dr. Daniel Fraser (MBBS, FRACP) – Physician

Question 1

Ethan, a 52-year-old man, presents to the Emergency Department with pain and swelling in his left leg for the past 24 hours. He returned from a 16-hour flight from London 3 days ago. He is otherwise healthy, with no significant past medical history, and is not on any medications. He smokes 10 cigarettes per day and works at a desk job. On examination, the left calf is erythematous, warm, and 4 cm larger than the right. Peripheral pulses are present, and there are no signs of infection.

Which of the following is the most significant predisposing factor for his presentation?

A) Smoking
B) Sedentary lifestyle
C) Long-haul air travel
D) Age over 50
E) Male sex

Correct Answer: C) Long-haul air travel

Explanation:
The most significant risk factor in this case is long-haul air travel, which leads to prolonged immobility. This promotes venous stasis in the lower limbs, one of the key elements in Virchow’s triad for thrombus formation. Although the patient is also a smoker and leads a sedentary life, these are chronic contributors. The acute onset of symptoms following prolonged immobility makes recent air travel the most relevant factor. Stasis causes pooling of blood, especially in the deep veins of the calf, increasing the risk of clot formation. Age and male sex slightly increase risk but are not key triggers here.

Question 2

Rachel, a 37-year-old woman, presents with a 2-day history of pain, swelling, and tightness in her left leg. She is 3 weeks postpartum after an uncomplicated vaginal delivery. She reports no fever, trauma, or injury. Examination reveals a swollen, warm, and tender left calf, with a positive Homan’s sign. Her vital signs are stable, and there is no shortness of breath or chest pain.

Which of the following is the most appropriate initial investigation?

A) D-dimer test
B) CT pulmonary angiogram
C) Doppler compression ultrasonography
D) Venography
E) Complete blood count

Correct Answer: C) Doppler compression ultrasonography

Explanation:
Doppler compression ultrasonography is the investigation of choice for suspected DVT due to its high sensitivity and specificity, particularly for proximal DVTs. It is non-invasive, safe in pregnancy and postpartum, and immediately available in most clinical settings. D-dimer levels are often elevated during the postpartum period, reducing their utility due to poor specificity. CT pulmonary angiogram is not indicated unless a pulmonary embolism is suspected. Venography, though accurate, is invasive and rarely used due to the risks and discomfort involved. A CBC may support the diagnosis by ruling out other causes but is not diagnostic for DVT.

Question 3

James, a 45-year-old man, presents with sudden onset shortness of breath and pleuritic chest pain. He denies cough or fever. He returned from an overseas trip a week ago and noticed left leg swelling during the flight. On examination, he is tachypnoeic (RR 26/min), tachycardic (HR 110 bpm), and has an oxygen saturation of 91% on room air. ECG shows sinus tachycardia, and chest X-ray is normal.

What is the most appropriate next step in diagnosis?

A) Chest X-ray
B) Echocardiogram
C) CT pulmonary angiogram
D) D-dimer
E) ABG

Correct Answer: C) CT pulmonary angiogram

Explanation:
This patient presents with classic signs of pulmonary embolism (PE) — sudden dyspnoea, pleuritic chest pain, tachycardia, and recent immobility. CT pulmonary angiography (CTPA) is the gold standard for diagnosing PE in hemodynamically stable patients. While D-dimer is useful in ruling out PE in low-risk patients, this patient has a high pretest probability, making CTPA the best immediate diagnostic tool. Chest X-ray and ABG can support the diagnosis but are not specific. An echocardiogram is useful in massive PE to assess right heart strain but is not first-line in stable patients.

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6. Hematology Module

6.1 Anemia

6.2 Thrombocytopenia

6.3 Thromboembolism

6.4 Anti-Coagulation

6.5 Lymphomas

6.6 Other Hematological Disorders

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