Hepatobiliary abnormalities associated with total parenteral nutrition.

Evidence of hepatic dysfunction (clinically, chemically, and morphologically) and biliary-tract abnormalities is common in patients receiving TPN. The entity might present as hepatocellular injury (fatty liver, steatonecrosis), intrahepatic cholestasis, acalculous cholecystitis, or cholelithiasis. Infants manifest primarily intrahepatic cholestasis, whereas adults manifest fatty liver early and intrahepatic cholestasis later in the course of therapy. Both groups are at risk for the development of biliary-tract abnormalities. Although most of these changes in the adult are mild and reversible, a small number of patients have recently been reported to develop progressive liver disease. In infants, however, the changes may be more severe, and lead more frequently to progressive liver disease and death. Although this progression to chronic liver disease is worrisome, it is uncertain whether, in patients on long-term therapy, it is due to the TPN or to other conditions or therapies associated with their clinical condition. The pathogenesis of each of these lesions may be multifactorial, including carbohydrate overfeeding, essential-fatty-acid deficiency, amino-acid deficiencies or imbalances, carnitine deficiency, bile-salt toxicity, lipid emulsions, bile-flow reduction, and gallbladder stasis. Therapies in these patients are aimed at alterations in the preceding etiologies (decreased glucose loads, contraction of the gallbladder). Further work is necessary to delineate the exact mechanisms of this entity, especially with regard to the causal relationships of TPN and this entity and to the development of chronic liver disease.