Biliary atresia

Posted Sun, 06/07/2009 - 09:18 by Shweta Bhatt
Images

Figure 1. Hepatobiliary scan


Clinical History:

13 day old ,former 37 weeker, with direct hyperbilirubinemia


Findings:

Hepatobiliary scintiscan using 0.98 mCi of Technetium 99m Choletec administered intravenously, followed by standard anterior abdominal image acquisition. Delayed images were obtained at 24 hours. There is persistent high background activity at 4.5 and 24 hours. There is gradual uptake of radiotracer by the liver and significant vicarious renal excretion into the urinary bladder. There is no visualization of the small bowel at 4.5 or at 24 hours.


Diagnosis:

Biliary atresia


Discussion:

Biliary atresia (BA) is a rare condition of the newborns involving the hepatobiliary system in which there is fibrosis and obliteration of the biliary tract following an inflammatory process. It eventually leads to liver failure if not treated . It is the commonest cause of chronic cholestasis in infants and children.

There are 2 clinical forms of BA (1):
Embryonic or fetal type (35%)
1. Early onset of neonatal cholestasis.
2. No jaundice-free period after physiological jaundice.
3. No bile duct remnants in hepatoduodenal ligament.
4. Associated congenital anomalies (10-20% of cases).

Perinatal type (65%)
1. ‘‘Later onset’’ of neonatal cholestasis.
2. Jaundice-free interval may be present after physiological
jaundice.
3. Remnants of bile duct structures found in hepatoduodenal
ligament.
4. No associated congenital anomalies.

There are 3 types of BA depending on the part of the extrahepatic duct involved:
Type I - obliteration of the common duct; the proximal ducts are patent
Type II - atresia of the hepatic duct, with cystic structures found in the porta hepatis
Type III (>90% of patients) - atresia of the right and left hepatic ducts to the level of the porta hepatis.

BA is most commonly seen in Asian population. Pathogenesis of this entity is not clear.
Patients present with jaundice, dark urine, and light stools.
Diagnosis of BA is typically made using hepatobiliary scintigraphy using technetium labeled diisopropyl iminodiacetic acid (DISIDA) nuclear scintiscan. Ultrasound is used to exclude other possible etiologies of the hepatobiliary system such as a choledochal cyst.
Hepatobiliary scintigraphy with phenobarbital pretreatment is a sensitive, specific, and accurate method of distinguishing
among neonatal hepatitis, biliary atresia, and choledochal cyst .The final diagnosis and subsequent therapy of persistent
neonatal jaundice is determined by hepatobiliary function: hepatic extraction and excretion of tracer into the gastrointestinal tract. In BA , there is normal hepatic extraction but no excretion of the radiotracer into the gastrointestinal tract (2,3)
Surgery ( Kasai portoenterostomy or liver transplant) is the only definite treatment for patients with BA.


References / Suggested Reading:

1. Desmet VJ. Congenital diseases of intrahepatic bile ducts: variation on the theme ‘‘Ductal Plate Malformation.’’ HEPATOLOGY1992;16:1069-1083
2. Kirks DR, Coleman RE, Filston HC et al. An imaging approach to persistent neonatal jaundice. American Journal of Roentgenology, Vol 142, Issue 3, 461-465
3. Gerhold JP, Klingensmith III, WC, Kuni CC et al. Diagnosis of biliary atresia with radionuclide hepatobiliary imaging. Radiology, Vol 146, 499-504


Author

Shweta Bhatt, MD and Vikram S Dogra, MD

Assistant Professor (SB) and Professor (VSD) of Radiology

University of Rochester , Rochester, NY

  • Delicious
  • Digg
  • StumbleUpon
  • Reddit
  • Newsvine
  • Furl
  • Facebook
  • Google
  • Yahoo