Clinical Challenge Pulmonary Dysfunction in Chronic Liver Disease

Pulmonary abnormalities and symptoms are common in patients with chronic liver disease. If questioned, up to 70% of cirrhotic patients undergoing evaluation for liver transplantation complain of dyspnea.1 In screening studies of patients with chronic liver disease, arterial blood gas abnormalities are found in as many as 45% and abnormal pulmonary function tests in as many as 50%.2 A variety of causes for pulmonary dysfunction in liver disease have been identified and include intrinsic cardiopulmonary disorders not specifically related to liver disease as well as unique problems associated with the presence of liver disease and/or portal hypertension (Table 1). The recognition that a subset of patients with hepatic disease develop significant pulmonary vascular alterations, either microvascular dilation leading to the hepatopulmonary syndrome (HPS) or arteriolar vasoconstriction leading to portopulmonary hypertension, indicates that unique changes in the pulmonary vasculature may occur in liver disease. These pulmonary vascular syndromes significantly impact morbidity and mortality in affected patients and influence candidacy for liver transplantation. This review will focus on the most common abnormality in the pulmonary vasculature in liver disease: HPS. It will address the differential diagnosis, clinical features, diagnostic evaluation, therapy, and pathogenesis of this increasingly well-recognized syndrome.