MCQs on Pulmonary Vascular Diseases

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

Question 1

A 40-year-old woman presents to the Emergency Department with sudden-onset chest pain, dyspnea and a fever of 39°C. She has arrived from Canada to Sydney 2 days ago by air. Which one of the following would be the most appropriate next step in management?

A) Chest X-ray (CXR).
B) ABG.
C) Computed tomography pulmonary angiography (CTPA).
D) V/Q scan.
E) D-dimer assay.

Correct Answer: A) Chest X-ray (CXR).

Air travel longer than 3 hours is a risk factor for venous thromboembolism, including pulmonary embolism (PE). The patient’s presentation of sudden-onset dyspnea and chest pain raises concern for PE. However, the presence of fever (39°C) makes an infectious cause more likely or equally likely, such as pneumonia or other respiratory infections.

A chest X-ray (CXR) is the initial and most appropriate next step in the emergency setting to evaluate for other potential causes of the patient’s symptoms (e.g. pneumonia, pneumothorax). It also helps to exclude alternative diagnoses before pursuing advanced imaging for PE.

(Option B) ABG may show hypoxia or hypocapnia in PE but is non-specific and does not change the immediate management plan.
(Option C and D) CTPA and V/Q scan are definitive investigations for PE but should be ordered only after an initial assessment, such as CXR, especially when fever is present.
(Option E) D-dimer is helpful in low-to-moderate probability cases, but again, initial imaging is preferred to rule out more likely causes in febrile patients before using it to assess for PE.

Hence, a chest X-ray is the most appropriate next step in this scenario.

Question 2

A 26-year-old woman presents to the emergency department with shortness of breath and pleuretic chest pain. Based on the history and clinical findings, she is suspected to have pulmonary embolism. She has a family history of thrombophilia. Which one of the following is the investigation of choice for her?

A) Duplex Doppler ultrasound scan of lower limbs.
B) Chest X-ray (CXR).
C) V/Q scan.
D) Computed tomogram pulmonary angiogram (CTPA).
E) D-dimer assay.

Correct Answer: C) V/Q scan.

Ventilation/perfusion (V/Q) scan is the preferred diagnostic test for suspected pulmonary embolism (PE) in young women of reproductive age (<55 years) due to lower radiation exposure to the breast tissue compared to CTPA. While CTPA is generally the first-line investigation in most patients suspected of PE, V/Q scan is safer in this specific demographic group to minimize long-term risk, particularly breast cancer.

(Option A) Duplex Doppler ultrasound is used to detect deep vein thrombosis (DVT), which can be an indirect source of PE, but is not the first choice for diagnosing PE in the absence of leg symptoms.
(Option B) Chest X-ray is important to rule out other diagnoses but is not diagnostic for PE due to low sensitivity and specificity.
(Option D) CTPA is highly accurate and preferred in most adults, but should be avoided in women under 55 when alternatives like V/Q scan are available.
(Option E) D-dimer is a screening tool used in patients with low or intermediate probability of PE. It is not definitive or sufficient on its own for diagnosis.

Thus, in this 26-year-old woman, V/Q scan is the most appropriate initial diagnostic investigation for suspected pulmonary embolism.

Question 3

A 62-year-old man presents to the emergency department with sudden-onset chest pain and shortness of breath. He has chronic kidney disease and a documented reduced GFR of 25 ml/min. On examination, his blood pressure is 110/75 mmHg and pulse is 112 bpm. An ECG is performed and is normal. A chest X-ray shows a wedge-shaped opacity in the periphery of the right lung. Which one of the following should be the next investigation to consider for this patient?

A) Duplex Doppler ultrasound of lower limbs
B) D-dimer assay
C) Computed tomography pulmonary angiography (CTPA)
D) Arterial blood gas (ABG) analysis
E) V/Q scan

Correct Answer: E) V/Q scan

This patient presents with features suggestive of pulmonary embolism (PE): acute onset dyspnea, pleuritic chest pain, tachycardia, and a wedge-shaped opacity on chest X-ray (indicative of pulmonary infarction).

Although CT pulmonary angiography (CTPA) is generally the preferred imaging modality for diagnosing PE due to its superior sensitivity and ability to detect alternative diagnoses, it requires intravenous contrast. Given this patient’s chronic kidney disease and low GFR (25 ml/min), the use of contrast in CTPA poses a significant risk of contrast-induced nephropathy and should be avoided.

Therefore, the V/Q (ventilation-perfusion) scan becomes the investigation of choice in this scenario. It does not involve contrast, making it safer for patients with renal impairment. While CXR abnormalities (like the wedge-shaped opacity) can sometimes reduce the specificity of V/Q scans, the renal risk from contrast exposure outweighs this concern.

(Option A) Doppler ultrasound can identify DVT, which supports the diagnosis of PE, but it is not diagnostic for PE.
(Option B) D-dimer is more useful in low-risk patients. In this high-risk scenario, imaging is directly warranted.
(Option C) CTPA is contraindicated here due to the patient’s renal dysfunction.
(Option D) ABG may show hypoxia, but it is not specific and cannot confirm the diagnosis.

Summary: For patients with suspected PE and renal impairment, a V/Q scan is the safest and most appropriate diagnostic test.

Previous Next

3. Respiratory Module

3.1 Asthma & COPD

3.2 Pulmonary Vascular Diseases

3.3 Pleural Diseases

3.4 Lung Cancer

3.5 Other Lung Diseases

Back to MCQ Bank