Diseases of the hepatopulmonary axis

Hepatopulmonary syndrome is the most widely recognized of the processes ass ociated with end-stage liver disease. Chronic liver dysfunction is associat ed with pulmonary manifestations due to alterations in the production or cl earance of circulating cytokines and other mediators. Hepatopulmonary syndr ome results in hypoxemia due to pulmonary vasodilatation with significant a rteriovenous shunting and ventilation-perfusion mismatch. Hepatic hydrothor ax may develop in patients with cirrhosis and ascites. Rarely, pulmonary hy pertension occurs in the setting of portal hypertension. A second group of disorders may primarily affect the lungs and liver (the hepatopulmonary axi s). Among these are the congenital conditions al-antitrypsin deficiency and cystic fibrosis. Autoimmune liver disease may be associated with lymphocyt ic interstitial pneumonitis, fibrosing alveolitis, intrapulmonary granuloma s, and bronchiolitis obliterans with organizing pneumonia. Sarcoidosis affe cts the lung and liver in up to 70% of patients. Medications such as amioda rone can result in a characteristic radiologic appearance of pulmonary and hepatic toxic effects. Knowledge of these associations will assist the radi ologist in forming a meaningful differential diagnosis and may influence tr eatment decisions.