Biliary atresiaFrom Wikipedia, the free encyclopedia

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Extrahepatic Biliary atresia

Operative view of complete extrahepatic biliary atresia.

Classification and external resources

Specialty medical genetics

ICD-10 Q44.2

ICD-9-CM 751.61

OMIM 210500

DiseasesDB 1400

MedlinePlus 001145

eMedicine ped/237

MeSH C06.130.120.123

[edit on Wikidata]

Biliary atresia, also known as extrahepatic ductopenia and progressive obliterative cholangiopathy, is a childhood disease of theliver in which one or more bile ducts are abnormally narrow, blocked, or absent. It can be congenital or acquired. As a birth defect innewborn infants, it has an incidence of one in 10,000–15,000 live births in the United States,[1] and a prevalence of

one in 16,700 in the British Isles.[2][3] Biliary atresia is most common in East Asia, with a frequency of one in 5,000.

The causes of biliary atresia are not well understood. Congenital biliary atresia has been associated with certain genes, while acquired biliary atresia is thought to be a result of an autoimmune inflammatory response, possibly due to a viral infection of the liver soon after birth.[4] The only effective treatments[citation needed] are surgeries such as the Kasai procedure and liver transplantation.

Contents  [hide] 

1Signs and symptoms 2Pathophysiology

o 2.1Geneticso 2.2Toxins

3Diagnosis 4Treatment 5Epidemiology 6References 7External links

Signs and symptoms[edit]

A video explanation of biliary atresia

Initially, the symptoms of biliary atresia are indistinguishable from those of neonatal jaundice, a usually harmless condition commonly seen in infants. Distinctive symptoms of biliary atresia are usually evident between one and six weeks after birth. Infants and children with biliary atresia develop progressive cholestasis, a condition in which bile is unable to leave the liver and builds up inside of it. When the liver is unable to excrete bilirubin through the bile ducts in the form of bile, bilirubin begins to accumulate in the blood, causing symptoms. These symptoms include yellowing of the skin, itchiness, poor absorption of nutrients (causing delays in growth), pale stools, dark urine, and a swollen abdomen. Eventually, cirrhosis with portal hypertension will develop. If left untreated, biliary atresia can lead to liver failure. Unlike other forms of liver failure, however, biliary-atresia-related liver failure does not result in kernicterus, a form of brain damage resulting from liver dysfunction. This is because in biliary atresia, the liver, although diseased, is still able to conjugate bilirubin, andconjugated bilirubin is unable to cross the blood–brain barrier.

Pathophysiology[edit]

The cause of biliary atresia is unknown. Many possible causes have been proposed, such as reovirus 3 infection,[5] congenital malformation, congenital cytomegalovirusinfection,[6] and autoimmunity.[7] However, experimental evidence is insufficient to confirm any of these theories.[8]

There have been extensive studies of the pathogenesis and proper management of progressive cirrhosis.[citation needed] When the biliary tract cannot transport bile to theduodenum, bile is retained in the liver (a condition known as cholestasis), which results in cirrhosis of the liver. Small bile ductules proliferate, and peribiliary fibroblasts are activated. These "reactive" biliary epithelial

cells produce and secrete cytokines such as CCL-2 or MCP-1, tumor necrosis factor (TNF), interleukin-6 (IL-6), TGF-beta, endothelin (ET), and nitric oxide (NO). Among these, TGF-beta is the most important pro-fibrogenic cytokine that can be seen in progressive cirrhosis. During the chronic activation of biliary epithelium and progressive cirrhosis, patients eventually show signs and symptoms of portal hypertension, such as esophagogastric varix bleeding, hypersplenism, hepatorenal syndrome, and hepatopulmonary syndrome. The latter two syndromes are essentially caused by systemic mediators that maintain the body in a hyperdynamic state.[citation needed]

There are three main types of extra-hepatic biliary atresia:

Type I: Atresia is restricted to the common bile duct. Type II: Atresia of the common hepatic duct. Type III: Atresia of the right and left hepatic duct.

In approximately 10% of cases, anomalies associated with biliary atresia include heart lesions, polysplenia, situs inversus, absent venae cavae, and a preduodenal portal vein.[citation needed]