Liver and lung diseases: Hepatopulmonary syndrome and portopulmonary hypertension

Abstract

Interactions of the liver and lung are observed in several pathological conditions. These interactions are classified into three types. In such as hypoxic hepatitis and nonalcoholic fatty liver disorder in the patients with obstructive sleep apnea, the functional abnormalities of the respiratory system, hypoxemia in this disorder, cause liver abnormalities. In sarcoidosis and α1-antitrypsin deficiency, both the lung and liver are affected together by the common underlying pathologies. And, the well-known and most unique interactions between the lung and liver are observed in hepatopulmonary syndrome and portopulmonary hypertension. Hepatopulmonary syndrome is characterized by the presence of liver disease and/or portal hypertension, increased alveolar-arterial oxygen gradient, and the evidence of intrapulmonary vascular dilatations. Portopulmonary hypertension is characterized by the combination of pulmonary hypertension and portal hypertension with or without liver diseases. Since these two diseases have very unique pathophysiology and significantly affect the quality of life and prognosis of the patients, in this chapter, recent understanding of their clinical manifestation, pathophysiology, diagnostic strategy, and treatment will be discussed.