A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A 61-year-old man comes to the physician for shortness of breath and chest discomfort that is becoming progressively worse. He has had increasing problems exerting himself for the past 5 years. He is now unable to walk more than 50 m on level terrain without stopping and mostly rests at home. He has smoked 1–2 packs of cigarettes daily for 40 years. He appears distressed. His pulse is 85/min, blood pressure is 140/80 mm Hg, and respirations are 25/min. Physical examination shows a plethoric face and distended jugular veins. Bilateral wheezing is heard on auscultation of the lungs. There is yellow discoloration of the fingers on the right hand and 2+ lower extremity edema. Which of the following is the most likely cause of this patient's symptoms?
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A
Elevated pulmonary artery pressureCorrect. Chronic hypoxic pulmonary vasoconstriction in long-standing COPD elevates pulmonary artery pressure, causing right ventricular hypertrophy and failure (cor pulmonale) — exactly this patient's plethora, JVD, and edema.
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B
Chronic respiratory acidosisIncorrect. Chronic respiratory acidosis is present in advanced COPD but is a consequence of CO2 retention; the systemic congestion and right-sided failure are directly explained by elevated pulmonary artery pressure, not acidosis.
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C
Coronary plaque depositsIncorrect. Coronary plaque (CAD) causes angina or LV failure with pulmonary congestion — not the right-sided heart failure pattern (JVD, peripheral edema) in a smoker with wheezing and plethora.
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D
Decreased intrathoracic gas volumeIncorrect. COPD produces INCREASED intrathoracic gas volume (hyperinflation) from air trapping — the opposite of decreased lung volume.
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E
Bronchial hyperreactivity to inhaled allergensIncorrect. Allergen-driven bronchial hyperreactivity describes asthma — episodic, reversible obstruction in a young patient — not the chronic, smoking-related hypoxic vasoconstriction that produces cor pulmonale in this 40-pack-year smoker.
↑ Tap an answer to reveal the reasoning
Answer: A. A long-term smoker (40 pack-years), nicotine-stained fingers, progressive exertional dyspnea, wheezing, plethoric face, JVD, and bilateral lower-extremity edema has cor pulmonale from COPD. The clinical picture is right heart failure secondary to chronic lung disease, driven by elevated pulmonary artery pressure.
The pathophysiology: chronic alveolar hypoxia from emphysema/chronic bronchitis causes pulmonary vasoconstriction (hypoxic pulmonary vasoconstriction is normally protective by matching ventilation to perfusion, but chronic generalized hypoxia produces sustained vasoconstriction and vascular remodeling). Over years, the pulmonary vascular bed becomes fixed-narrowed, pulmonary artery pressure rises, and right ventricular afterload increases. The right ventricle hypertrophies and eventually fails — producing systemic venous congestion (JVD, hepatomegaly, peripheral edema) with relatively preserved left ventricular function.
Distinguish: chronic respiratory acidosis IS present but is a consequence of CO2 retention, not the direct cause of the cor pulmonale findings; coronary plaque/CAD would produce angina and LV failure (pulmonary edema, S3) rather than right-sided failure; "decreased intrathoracic gas volume" is the opposite of COPD (which features increased lung volumes and hyperinflation). The unifying answer is elevated pulmonary artery pressure causing cor pulmonale.
**Why each option:**
**A.** Chronic hypoxic pulmonary vasoconstriction in long-standing COPD elevates pulmonary artery pressure, causing right ventricular hypertrophy and failure (cor pulmonale) — exactly this patient's plethora, JVD, and edema.
**B.** Chronic respiratory acidosis is present in advanced COPD but is a consequence of CO2 retention; the systemic congestion and right-sided failure are directly explained by elevated pulmonary artery pressure, not acidosis.
**C.** Coronary plaque (CAD) causes angina or LV failure with pulmonary congestion — not the right-sided heart failure pattern (JVD, peripheral edema) in a smoker with wheezing and plethora.
**D.** COPD produces INCREASED intrathoracic gas volume (hyperinflation) from air trapping — the opposite of decreased lung volume.