Атрезія жовчних шляхів

Infants with biliary atresia are jaundiced and often have dark urine (containing conjugated bilirubin), acholic stools, and hepatosplenomegaly. The presence of cholestatic jaundice at 2 weeks of age in an otherwise healthy infant warrants investigation to determine the underlying cause. The differential diagnosis includes many other etiologies, but early diagnosis of biliary atresia is crucial because portojejunostomy (Kasai procedure) before 45 to 60 days of life gives the infant the best chance for survival with the native liver (1).

By 2 to 3 months of age, infants may have poor growth with malnutrition, pruritus, irritability, and splenomegaly.

Untreated, hepatic fibrosis progresses to cirrhosis resulting in portal hypertension, abdominal distention resulting from ascites, dilated abdominal veins, and upper gastrointestinal bleeding resulting from esophageal varices.

• Total and direct bilirubin

• Liver function tests

• Serum alpha-1 antitrypsin levels (to rule out alpha-1 antitrypsin deficiency)

• Sweat chloride test (to rule out cystic fibrosis)

• Abdominal ultrasonography

• Hepatobiliary scan

• Usually, liver biopsy and intraoperative cholangiography

Biliary atresia is identified by an elevation in both total and direct bilirubin. The serum alpha-1 antitrypsin levels should be determined because alpha-1 antitrypsin deficiency is another relatively common cause of cholestasis. Tests that are needed to evaluate the liver include albumin, liver enzymes, prothrombin time/partial thromboplastin time (PT/PTT), and ammonia level.

The sweat chloride concentration should also be determined to rule out cystic fibrosis (1). Frequently, additional testing is needed to evaluate for other metabolic, infectious, genetic, and endocrine causes of neonatal cholestasis. Elevated serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) levels, and gamma-glutamyl transferase (GGT) support the diagnosis of biliary atresia but do not rule out other forms of cholestasis.

Abdominal ultrasonography is noninvasive and can assess liver size and certain abnormalities of the gallbladder and common bile duct. Infants with biliary atresia often have a small contracted gallbladder or one that cannot be seen. However, these findings are nonspecific. A hepatobiliary scan using hydroxy iminodiacetic acid (HIDA scan) should also be done; excretion of contrast into the intestine rules out biliary atresia, but lack of excretion is not diagnostic of biliary atresia, because severe neonatal hepatitis and other causes of cholestasis may also cause little or no excretion.

A definitive diagnosis of biliary atresia is made with a liver biopsy and intraoperative cholangiography. Sometimes, ERCP (endoscopic retrograde cholangiopancreatography) can be done to aid in the diagnosis. The classic histologic findings are enlarged portal tracks with fibrosis and bile duct proliferation. Bile plugs may also be noted in the bile ducts. Intraoperative cholangiography reveals the lack of a patent extrahepatic bile duct.

• Intraoperative cholangiogram

• Portojejunostomy (Kasai procedure)

• Frequently liver transplantation

Infants with presumed biliary atresia require surgical exploration with an intraoperative cholangiogram. If biliary atresia is confirmed, a portojejunostomy (Kasai procedure) should be done as part of the same surgical procedure. Ideally, this procedure should be done in the first month of life. If done 60 days or more after birth, the prognosis significantly worsens.

Postoperatively, many patients have significant chronic problems, including persistent cholestasis, recurrent ascending cholangitis, and failure to thrive. If cholestasis persists for ≥ 3 months postoperatively, referral to a transplant center should be considered. Prophylactic antibiotics (eg, trimethoprim/sulfamethoxazole or neomycin) are frequently prescribed for a year postoperatively in an attempt to prevent ascending cholangitis. Medications that increase bile production (choleretic agents), such as ursodiol, are frequently used postoperatively. Nutritional therapy including supplemental fat-soluble vitamins (A, D, E, and K) is very important to ensure adequate intake to support growth (1). Even with optimal therapy, approximately 50% of infants will develop cirrhosis and require liver transplantation.

Frequently, infants who cannot undergo portojejunostomy require liver transplantation by 1 year of age.

Biliary atresia is progressive and, if untreated, results in cirrhosis with portal hypertension by several months of age, then liver failure and death by 1 year of age. Portojejunostomy is ineffective in some infants and only palliative in most infants. Long-term survival after liver transplantation (with or without prior portojejunostomy) is approximately 80% (1, 2).