Liver and lung: Hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) is characterized by the triad of hepatic dysfunction, arterial hypoxemia, and intrapulmonary vascular dilatations. Patients with HPS may have symptoms of liver disease rather than respiratory symptoms, but typical respiratory signs and symptoms include exertional dyspnea, platypnea, and orthodeoxia. Portal hypertension, cutaneous spider nevi, and digital clubbing are highly suggestive of HPS. The diagnostic workup includes arterial blood gas measurements, contrast-enhanced echocardiography, and technetium 99m-labeled macroaggregated albumin scanning. Pulmonary angiography may be necessary to detect discrete arteriovenous communications. Pharmacologic agents, such as almitrine bismesylate, prostaglandin F_2α, indomethacin, somatostatin, and methylene blue, have been used to treat HPS, but results have been meager. Transjugular intrahepatic portosystemic shunt may improve oxygenation, and orthotopic liver transplantation may offer the best possibility for improvement.