Biliary Atresia and Choledochal Malformations

Biliary atresia (BA) is a peculiar disease of the newborn that is best characterised as a cholangiodestructive disease affecting all parts of the biliary tract. There is marked variation in incidence across the globe with the highest rates found in East Asian countries as compared to Europe and North America. Infants will invariably present with persisting conjugated jaundice and acholic stools within the first few weeks. There are a number of different variants which are aetiologically dissimilar encompassed within the phenotype “biliary atresia”. These can be overtly congenital with a primary failure of biliary development as seen in cases of cystic BA and those with the biliary atresia splenic malformation (BASM) syndrome. In others, there may be perinatal destruction of a formed biliary tree; with those showing anti-cytomegalovirus (CMV) immunoglobulin M (IgM)-+ve antibodies as the likeliest group. In others, referred to here as isolated BA, we simply do not have any firm evidence of their aetiology. Management for all remains palliative with the Kasai portoenterostomy; this remains an operation still best done as an open procedure. There is emerging evidence of the efficacy of postoperative high-dose steroids although at best this only involves a 10 % improvement in outcome. In a system with centralised referrals and high-volume surgical centres (UK), 5- and 10-year native liver survivals of 45-50 % have been achieved with an overall survival of ~ 90 % at 10 years. Choledochal malformation (CM) may be best defined as abnormal dilatation of the biliary tract, in the absence of any acute obstruction and can be broadly separated into two extrahepatic phenotypes: fusiform (type 1f) and cystic (type 1c). Moreover, both, if long standing, can be complicated by additional intrahepatic dilatation (type 4). All types are relatively rare in the West and far more common again in East Asian countries although their actual prevalence remains uncalculated. Most CMs present within childhood either in the first few years with jaundice or later on with recurrent abdominal pain (usually associated with pancreatitis). Most CMs appear in some way to be of congenital origin though the exact aetiology is unknown. There are two competing hypotheses: (a) dilatation secondary to stenosis of the distal bile duct and (b) dilatation of the bile duct due to reflux of activated pancreatic enzymes via the common pancreatobiliary channel and mural damage. Recent clinical studies suggest that the key mechanism is the former and is biliary pressure related. The principle aim of surgery is excision of the dilated extrahepatic biliary tract with proximal reconstruction (usually hepaticojejunostomy) using a Roux loop. Open surgery is still very much the standard in most North American and European centres, although laparoscopic excision and reconstruction has certainly become an option particularly in some high-volume Asian centres.