Systemic Disease and the Liver in Children

The liver is the largest parenchymal organ in the body and has a complicated circulatory system, with dual afferent blood supply from the portal vein and hepatic artery. Although the liver mass accounts for only 2.5% of adult body weight, it receives nearly 25% of the resting cardiac output and at any given time contains 10–15% of total body blood volume. In addition to serving as an important blood volume reservoir, the liver is also a complex metabolic organ with important functions in biosynthesis, innate immunity, metabolism and toxin/metabolite clearance. By virtue of its size, multiple metabolic functions, and prominent position in the circulatory system, the liver is frequently involved, either as an accomplice or as an innocent bystander, in a range of systemic, circulatory and inflammatory disorders. This chapter reviews hepatic involvement in common, and some uncommon, systemic diseases affecting children and young adults.