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Pulmonary veno-occlusive disease — SCE Respiratory MCQ

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HardImagingPulmonary veno-occlusive diseaseSCE Respiratory

A 46-year-old man is referred with progressive exertional dyspnoea and presyncope. He had a provoked pulmonary embolism 4 years earlier and completed 6 months of anticoagulation. His resting oxygen saturation is 86% on air. Spirometry and lung volumes are normal, but TLCO is 31% predicted. Echocardiography shows severe right ventricular dilatation with preserved left ventricular systolic function and a normal-sized left atrium. Right heart catheterisation demonstrates a mean pulmonary arterial pressure of 43 mmHg, pulmonary arterial wedge pressure of 9 mmHg and pulmonary vascular resistance of 8.2 Wood units. Ventilation–perfusion SPECT is normal. High-resolution CT shows diffuse centrilobular ground-glass opacities, smooth interlobular septal thickening and mediastinal lymphadenopathy, without emphysema or pulmonary fibrosis. Within 24 hours of starting sildenafil, he develops pulmonary oedema despite unchanged left ventricular function. Which diagnosis best integrates these findings?

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Correct answer: E — Pulmonary veno-occlusive disease

Explanation lettering: E = shown as B · B = shown as C · C = shown as D · D = shown as E

This is pulmonary veno-occlusive disease (PVOD). Catheterisation establishes precapillary pulmonary hypertension: the pulmonary arterial pressure and vascular resistance are raised while the wedge pressure is normal. A normal wedge pressure does not exclude PVOD because wedging reflects pressure in larger pulmonary veins, whereas PVOD predominantly obstructs small pulmonary veins and venules. The disproportionately severe hypoxaemia and reduction in TLCO, despite preserved lung volumes, provide important physiological clues. HRCT supplies the characteristic imaging combination of centrilobular ground-glass opacities, smooth septal thickening and mediastinal lymphadenopathy. Pulmonary oedema after pulmonary arterial vasodilatation, in the absence of left ventricular failure, is a further strong discriminator because increased arterial inflow is delivered against an obstructed pulmonary venous bed. A is initially plausible because of the previous embolism, but a normal V/Q SPECT effectively excludes chronic thromboembolic disease in this setting. B can cause septal thickening and oedema, but the normal wedge pressure, left atrial size and left ventricular assessment argue against post-capillary pulmonary hypertension. C explains the precapillary haemodynamics but not the full CT triad, markedly reduced TLCO and vasodilator-induced oedema. E may produce pulmonary hypertension, lymphadenopathy and ground-glass change, but there are no characteristic perilymphatic nodules, upper-zone fibrosis or other evidence of sarcoidosis.

Reference: 2022 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension (2023) — https://publications.ersnet.org/content/erj/61/1/2200879 Pulmonary veno-occlusive disease: a clinical review (2025) — https://publications.ersnet.org/content/breathe/21/1/240098