The liver in pediatric gastrointestinal disease.

Hepatic involvement is often encountered in gastrointestinal (GI) diseases, in part because of the close anatomic and physiologic relations between the liver and GI tract. Drainage of the mesenteric blood supply to the portal vein permits absorbed and/or translocated nutrients, toxins, bacterial elements, cytokines, and immunocytes to gain hepatic access. Liver problems in digestive disorders may range from nonspecific hepatocellular enzyme elevations to significant pathologic processes that may progress to end-stage liver disease. Hepatobiliary manifestations of primary GI diseases in childhood and adolescence are not uncommon and include several well-described associations, such as sclerosing cholangitis with inflammatory bowel disease. Liver damage may also result from the effects of drugs used to treat GI diseases, for example, the hepatotoxicity of immunomodulatory therapies. This review highlights the important features of the hepatic and biliary abnormalities associated with 3 common pediatric GI conditions: inflammatory bowel disease, celiac disease, and cystic fibrosis.