Hepatic and Biliary Disease

Chapter 78 Hepatic and Biliary Disease



The pulmonary consequences of liver disorders can be classified according to whether they predominantly affect the pleural space, the lung parenchyma, or the pulmonary circulation. Unique pulmonary abnormalities occur in patients with severe alpha1-antitrypsin deficiency, primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC). The impact of hepatic dysfunction on the respiratory system during sleep has recently been appreciated (Table 78-1).


Table 78-1 Major Pulmonary Consequences of Portal Hypertension (with or Without Cirrhosis)


















Area/Disorder Complications
Pleural space
Pulmonary parenchyma
Pulmonary circulation
Sleep-disordered breathing

HCV, hepatitis C virus; NSIP, nonspecific interstitial pneumonia; PBC, primary biliary cirrhosis; PSC, primary sclerosing cholangitis; SaO2, arterial oxygen saturation; UIP, usual interstitial pneumonia.


Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) are the major pulmonary vascular problems that complicate portal hypertension from any cause. HPS, a pulmonary vascular dilation abnormality leading to arterial hypoxemia, occurs in 5% to 15% of patients with portal hypertension. POPH, resulting from pulmonary vascular obstruction or obliteration, has been reported in 4% to 16.5% of patients with advanced liver disease. Pleural effusions related to the formation of ascites develop in 5% to 10% of cirrhotic patients.


Pulmonary function abnormalities can be demonstrated in approximately 50% of patients with advanced liver disease. The most common abnormality is a reduced diffusing capacity for carbon monoxide (DLCO). Abnormal oxygenation measured by increased alveolar-arterial oxygen gradient or reduced arterial oxygen tension (PaO2) is common (40%-50%). Nocturnal oxygenation abnormalities are also common (~50%) and underdiagnosed in patients with advanced liver disease.




Pathophysiology


Circulating mediators, associated with the probable genetic predisposition, appear to cause HPS or POPH. Such mediators (causing vasodilation or vasoproliferation, respectively) could arise because of the abnormal metabolism of the dysfunctional liver. However, such specific circulating mediators have yet to be identified in humans.











Jun 12, 2016 | Posted by in RESPIRATORY | Comments Off on Hepatic and Biliary Disease

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