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Helpful Review on Biliary Atresia

August 19, 2015 7:00 am

Biliary atresia (BA) remains the leading cause of pediatric liver transplantation and a frequent cause of cholestasis in newborns. A recent review (AG Feldman, CL Mack. JPGN 2015; 61: 167-75) provides a helpful update. The article begins with a review on pathogenesis, though this remains unknown and continues to be an area of speculation.

The section on evaluation includes a suggested diagnostic algorithm for neonatal cholestasis. In short, for a 2 week old with jaundice , the authors recommend (STEP 1) fractionating the bilirubin. The infant is considered cholestasis if the direct bilirubin is ≥1 mg/dL (if total bilirubin is <5 mg/dL) or if direct bilirubin ≥20% of total bilirubin (if total bilirubin is >5 mg/dL).

Among cholestatic infants, the authors recommend (STEP 2) next checking ultrasound and alpha-one antitrypsin (A1AT) (level & phenotype). The text implies that the authors would check a GGTP. While this is not in their algorithm, many would suggest checking urine reducing substances, coags, serum glucose, and consideration of sepsis evaluation; these tests can identify issues that are more urgent than identifying biliary atresia.

STEP 3: If U/S and A1AT, are not diagnostic, consider urine culture, urine reducing substances, urine succinylacetone, and additional infectious studies.

STEP 4: Proceed with liver biopsy. If findings of biliary atresia (eg. bile plugs, bile duct proliferation, portal fibrosis), proceed with intraoperative cholangiogram.

Other points:

“It is rare for an infant with BA to have a GGTP level <200 U/L.” If low GGTP, consider PFIC, inborn error of bile acid metabolism, and panhypopituitarism.
Extensive differential diagnosis table given ((Table 1)
“Late diagnosis of BA remains a problem in the United States. The average age of HPE [hepatoportoenterostomy] is 61 days and 44% of patients still undergo HPE after 60 days of life.” The authors indicate a goal for HPE of taking place at <45 days of life.
Successful HPE can occur even with late diagnosis. 10% to 20% of children who undergo HPE after 100 to 120 days of life still have success in restoring bile flow.”
Early/successful HPE is helpful in increasing 10-year transplant-free rate. Early on, 3 months after HPE, those with a total bilirubin <2 mg/dL compared with those with a total bilirubin of >6 mg/dL have a much lower likelihood of liver transplantation by 2 years of age: 84% vs. 16%.
Recommends checking a pulse oximetry at routine followup visits following HPE to look for the possibility of hepatopulmonary syndrome.
The article reviews complications including ascites, portal hypertension/GI bleeding, cholangitis, malignancy, and hepatopulmonary syndrome/portopulmonary hypertension.
Outcomes: With HPE, “up to two-thirds of patients with BA have short-term clearance of jaundice.” Yet, “80% of patients with biliary atresia will require liver transplantation during childhood.”

Also noted:

“Biliary Atresia is Associated with Hypertension” JPGN 2015; 61: 182-86.

“Pathogenesis of biliary atresia: defining biology to understand clinical phenotypes” A Asai, A Miethke, JA Bezerra. Nat Rev Gastroenterol Hepatol 2015; 12: 343-52. This review provides in-depth review examines more precise phenotyping, influencing factors (eg. cytomegalovirus), and potential mechanisms.

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