[Parenteral nutrition-associated liver disease]

Parenteral nutrition associated liver disease (PNALD) is an important problem in patients who require longterm parenteral nutrition as well as in preterm infants. Prevalence varies according to different series. Clinical presentation is different in adults and infants. Although since its first descriptions several hypothesis have been elucidated, the aetiology is not quite clear. It is possible that different factors could be involved. PNALD risk factors can be classified in three groups: 1) those derived from the lack of enteral nutrition stimulus; 2) parenteral nutrition components acting as toxic or the lack of specific nutrients and 3) those due to the underlying disease. If PNALD appears in short-term PN and it presents only as a mild elevation of liver enzymes, there is no need to treat. On the contrary, when direct bilirubin is > 2 mg/dL and lasts longer, there is a need to consider different causes and to minimize risk factors. We review the different approaches to manage PNALD, including optimizing enteral nutrition, modify parenteral solutions, use of specific nutrients -taurine, choline, etc.- or the use of drugs (mainly ursodeoxicolic acid). If liver disease progresses to cirrhosis a liver transplant must be considered.