Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 61-year-old woman is evaluated for a 4-month history of progressive dyspnea and fatigue without chest pain. Eighteen months ago, she was diagnosed with liver cirrhosis due to nonalcoholic steatohepatitis (NASH). Medical history is also significant for obesity. Medications are propranolol, spironolactone, and lactulose.

On physical examination, temperature is 36.4 °C (97.5 °F), blood pressure is 112/64 mm Hg, pulse rate is 60/min, and respiration rate is 16/min; BMI is 36. Mild scleral icterus is noted. Cardiac examination reveals a prominent S₂. The lungs are clear. Dilated veins are visible on the trunk and abdomen, and there is no appreciable ascites. Trace symmetric ankle edema is noted.

Chest radiograph shows cardiomegaly and clear lung fields. Pulmonary function tests show normal spirometry but reduced diffusing capacity (42% of predicted). A resting echocardiogram shows a left ventricular ejection fraction of 70% and an estimated right ventricular systolic pressure of 58 mm Hg. No shunt is seen with contrast enhancement. A dobutamine stress echocardiogram is negative for ischemia. A ventilation-perfusion scan shows a low probability of pulmonary embolism. Right heart catheterization reveals a mean pulmonary artery pressure of 48 mm Hg and a pulmonary capillary wedge pressure of 12 mm Hg.

Which of the following is the most likely diagnosis?

A: Chronic thromboembolic pulmonary hypertension
B: Hepatopulmonary syndrome
C: Portopulmonary hypertension
D: Pulmonary veno-occlusive disease

MKSAP Answer and Critique

The correct answer is C: Portopulmonary hypertension.

The most likely diagnosis is portopulmonary hypertension. This diagnosis is suggested by evidence of pulmonary hypertension in the setting of portal hypertension, typically associated with liver cirrhosis. Pulmonary hypertension suggested by echocardiography was confirmed by right heart catheterization. In the classification of pulmonary hypertension, portopulmonary hypertension is part of group 1 (pulmonary arterial hypertension [PAH]). Although the coupling with portal hypertension makes the diagnosis of portopulmonary hypertension most likely, other causes of PAH (such as HIV infection, drug toxicity, connective tissue disease) should be ruled out. However, none of these other causes of PAH are likely in this patient.

This patient has no history of venous thromboembolism; however, some patients with chronic thromboembolic pulmonary hypertension (CTEPH) do not report a history of deep venous thrombosis. This patient’s low-probability ventilation-perfusion scan makes CTEPH very unlikely.

Hepatopulmonary syndrome is a disorder caused by dilated small vessels in the pulmonary vasculature resulting in shunting of blood, and it should be considered in a patient with liver disease who is hypoxic. Pulmonary hypertension is not a defining feature. Intrapulmonary shunting is confirmed by the appearance of contrast (bubbles from agitated saline) in the left heart following injection into a peripheral vein. In this patient, the contrast echocardiographic study was normal.

Pulmonary veno-occlusive disease (PVOD) is a rare cause of pulmonary hypertension caused by fibrous occlusion of distal pulmonary veins. Detection in this patient’s age group is unusual; most cases are diagnosed in children and young adults. PVOD is confirmed by pathology but can be suggested by radiographic abnormalities such as pleural effusions or a prominent interstitium on chest radiograph and septal thickening on chest CT. This patient had clear lung fields on chest radiograph. PVOD is much less likely than pulmonary hypertension in this patient.

Key Point

• The diagnosis of portopulmonary hypertension is suggested by evidence of pulmonary hypertension in the setting of portal hypertension.

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