Biliary atresia - triangular cord sign

Case contributed by Dr Anjum Bandarkar

Presentation

Jaundice with hyperbilirubinemia, transaminitis and elevated alkaline phosphatase and GGT. Total bilirubin level 6.4, direct bilirubin level 3.2. Exclusively breast-fed and otherwise healthy.

Patient Data

Age: 8 weeks
Gender: Female

The common bile duct is not visualized. At the porta, only two structures are identified, the portal vein and hepatic artery. There is increased echogenicity along anterior wall of portal vein consistent with positive triangular cord sign. The area of increased echogenicity measures 3.6 mm in maximum thickness on transverse scan. On oblique longitudinal view, the area of increased echogenicity is seen paralleling the anterior wall of right portal vein in the expected location of common hepatic duct. The gall bladder is hypoplastic with thick wall and multiseptated appearance. Gall bladder measures 17 mm long and 2.5 mm wide, considered diminutive. The pancreas and spleen are normal. Liver also appears normal in size and echotexture.

Case Discussion

Triangular cord sign represents the fibrous ductal remnant of the extrahepatic bile duct in biliary atresia. The objective criterion for positive triangular cord sign has been described as 4 mm thickness or more of the echogenicity along anterior wall of right portal vein on oblique longitudinal scan. In an infant presenting with hyperbilirubinemia and small diminutive gall bladder, sonographic visualization of the triangular cord sign can be invaluable in reliably predicting biliary atresia and helping to decide further management.

The infant underwent a liver biopsy which showed moderate to severe cholestasis and perforating bile ducts consistent with extrahepatic biliary atresia.

During exploratory laparotomy, a cholangiogram performed via a catheter in the remnant gallbladder did not show any tracking of the biliary system. Hence a portoenterostomy or Kasai procedure was performed.

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