Clinical History
A 47-year-old female presented with worsening dyspnoea and weakness. The patient was noted for HCV/HIV co-infection.
Imaging Findings
A pulmonary angiography CT was performed to exclude embolism. CT ruled out embolism and showed main pulmonary artery enlargement (figure 1a, b), and diffuse dilatation of the pulmonary vessels in the upper, middle and lower zones of both lungs (figure 2a, b, c). Small and hazy ground-glass areas were detected in lower zones (figure 2c).
A following contrast CT of the abdomen documented irregularity of the external contour of the liver, hypertrophy of the caudate and volume reduction of right lobe, findings consistent with cirrhotic changes, moreover splenomegaly, esophageal varices and ascites were found (figure 3).
A transthoracic doppler echocardiography revealed a value of 45mm Hg of the pulmonary artery pressure, result judged as sign of mild pulmonary hypertension.
Finally, laboratory tests documented elevated values of hepatic enzymes (aspartate aminotransferase and alanine aminotransferase) and decreased albumin.
On the basis of the described data, a hepatopulmonary syndrome and portopulmonary hypertension were suspected.
Discussion
Hepatopulmonary syndrome is defined as the triad of liver disease, increased alveolar-arterial oxygen gradient while breathing room air, and pulmonary vascular dilatation. It manifests clinically as progressive dyspnea, cyanosis, and clubbing in patients with cirrhosis, and is secondary to excessive vascular production of vasodilators, particularly nitric oxide [1, 2].
In our case, dyspnea, laboratory results consistent with liver failure and hypoxemia were identified. The radiologic manifestations of hepatopulmonary syndrome may include distal vascular dilatation associated with an abnormally large number of visible terminal vessel branches, more concentrated in the lower lung zones [1, 2].
Portopulmonary hypertension is defined as pulmonary artery hypertension that develops in a setting of portal hypertension. Dyspnea on exertion is the most common presentation [1, 2]. Suggested criteria for the diagnosis of portopulmonary hypertension are mean pulmonary artery pressure greater than 25 mm Hg at rest, increased pulmonary vascular resistance, pulmonary capillary wedge pressure less than 15 mm Hg, and evidence of portal hypertension [1].
We found CT and ecocardiographic signs of pulmonary hypertension, furthermore in absence of tromboembolism findings, and in an liver dysfunction setting, we correlated these data to a portopulmonary hypertension.
There are several mechanisms by which portal hypertension might causes pulmonary
hypertension; the presence of vasoactive substances, not metabolized by the diseased liver, such as serotonin, interleukin 1, endothelin 1, and thromboxane, might cause vasoconstriction in pulmonary arteries, or venous blood clots might pass through porto-systemic shunts and reach the pulmonary circulation, causing pulmonary hypertension, and finally, high cardiac output associated with cirrhosis might increased shear stress of the pulmonary artery causing vasoconstriction and proliferation of endothelial cells [1].
The differential diagnosis includes pulmonary edema and pulmonary veno-occlusive disease. Pulmonary edema is generally characterized by ground-glass opacity, interlobular septal thickening, peribronchovascular thickening, increased vascular caliber, and pleural effusion. Pulmonary veno-occlusive disease includes signs as smoothly thickened interlobular septa and ground-glass opacity, prominence of pulmonary artery and of right chambers of the heart. Finally, to date, liver transplant remains the only effective treatment of hepatopulmonary syndrome and portopulmonary hypertension, although post-transplant survival is often reduced compared with patients without hepatopulmonary syndrome and there are also reports on post-transplant progression of portopulmonary hypertension [2].
Differential Diagnosis List
Hepatopulmonary syndrome and portopulmonary hypertension
Veno-occlusive pulmonary disease
Pulmonary edema
Final Diagnosis
Hepatopulmonary syndrome and portopulmonary hypertension