Liver disease in cystic fibrosis

Liver disease associated with cystic fibrosis (CF) is considered a secondary effect of the basic defect of the disease, leading to obstruction of bile ductules by abnormal mucoid secretions; additional factors have been involved in the pathogenesis, such as abnormalities in bile acid metabolism, nutritional deficiencies, drug hepatotoxicity, stenosis of the common bile duct by the fibrotic pancreas. Clinical presentation of liver disease in CF is rare during the first few years of life, although neonatal cholestasis can be occasionally the first manifestation of the disease. Isolated massive steatosis has been reported in less than 5% of cases as a consequence of malnutrition. Focal biliary cirrhosis is the pathognomonic hepatic lesion and is present in 25-30% of CF patients, most of whom are asymptomatic. The focally distributed lesions can extend leading to multi-lobular biliary cirrhosis with occurrence of signs and symptoms of cirrhosis and portal hypertension. Early diagnosis of CF-associated liver disease is difficult since liver function tests may be normal even in cases of overt cirrhosis: no test has proved to be sufficiently sensitive and specific and even liver biopsy is of questionable relevance due to the focal distribution of hepatic lesions. Clinical examination is of major importance, since the presence of hepatomegaly seems to correlate well with the histologic finding of fibrosis. The rationale for the use of the choleretic non-toxic bile acid ursodeoxycholic acid in CF-associated liver disease is to reduce the viscosity of bile and to replace toxic bile acids which accumulate in the hepatocyte.(ABSTRACT TRUNCATED AT 250 WORDS)