Infants with biliary atresia (BA) can be grouped into three categories:
- Biliary atresia without any other anomalies or malformations – This pattern is sometimes referred to as perinatal BA, and occurs in 70 to 85 percent of infants with BA. Typically, these children are born without jaundice, but within the first two months of life, jaundice develops and stools become progressively acholic (pale color).
- Biliary atresia in association with laterality malformations – This pattern is also known as Biliary Atresia Splenic Malformation (BASM) or "embryonal" biliary atresia, and occurs 10 to 15 percent of infants with BA. The laterality malformations include situs inversus (reversal of the organs in their natural place), asplenia (no spleen) or polysplenia (multiple misshapen spleen), malrotation, interrupted inferior vena cava, and cardiac anomalies. Data suggest that children with BASM have poorer outcomes compared to those with perinatal BA.
- Biliary atresia in association with other congenital malformations – This occurs in the remaining 5 to 10 percent of BA cases; associated congenital malformations include intestinal atresia, imperforate anus, kidney anomalies, and/or heart malformations http://www.uptodate.com/contents/biliary-atresia
Type I: the common bile duct is obliterated while the proximal bile ducts are patent.
Type II: atresia of the hepatic duct is seen, with cystic bile ducts found at the porta hepatic.
Type IIa: the cystic and common bile ducts are patent, whereas in type IIb, the cystic, common bile duct, and hepatic ducts are obliterated.
Type III: atresia refers to discontinuity of the right and the left hepatic ducts to the level of the porta hepatis. This form of biliary atresia is common, accounting for more than 90% of cases.
http://emedicine.medscape.com/article/406335-overview
Type II: atresia of the hepatic duct is seen, with cystic bile ducts found at the porta hepatic.
Type IIa: the cystic and common bile ducts are patent, whereas in type IIb, the cystic, common bile duct, and hepatic ducts are obliterated.
Type III: atresia refers to discontinuity of the right and the left hepatic ducts to the level of the porta hepatis. This form of biliary atresia is common, accounting for more than 90% of cases.
http://emedicine.medscape.com/article/406335-overview