Biliary Atresia

 1:5,000 to 1:19,000 newborns






Clinical Issues




• Most common cause of pathologic infant jaundice
image Conjugated hyperbilirubinemia

– Neonatal jaundice

– Dark urine and pale stools

– Hepatomegaly

• Associated extrahepatic congenital anomalies present in up to 20% of cases

• Surgical intervention required
image Kasai procedure to reestablish bile flow; best outcome if performed before 45-60 days of age

image Most frequent indication for pediatric liver transplantation


Macroscopic




• Level of extrahepatic duct obliteration is most common within portal hepatis

• Associated with hypoplastic or atretic gallbladder


Microscopic




• Ductular reaction, duct/ductular bile plugs, and portal and periportal fibrosis

• Associated with lobular cholestasis, focal giant cell transformation, and extramedullary hematopoiesis

• Careful clinical and radiographic correlation required to exclude other entities in differential diagnosis


Top Differential Diagnoses




• Idiopathic neonatal hepatitis

• α-1-antitrypsin deficiency

• Total parenteral nutrition-associated cholestasis

• CMV infection

• Choledochal cyst

image
Portal Expansion and Ductular Reaction
Wedge liver biopsy specimen from an 8-week-old infant shows an expanded portal tract with ductular reaction. The ductules along the periphery contain bile plugs image .


image
Portal Expansion
Trichrome stain highlights the expanded portal tracts with associated ductular reaction in a liver biopsy specimen from a 7-week-old infant.

image
Gross Appearance
Explanted liver from a 12 year old with biliary atresia (BA) is cirrhotic. In the left lobe of the liver, a 0.9-cm yellow nodule image was discovered. Histologically, this was a well-differentiated hepatocellular carcinoma.

image
Biliary Remnant
Section of biliary remnant removed during Kasai procedure demonstrates a markedly narrowed bile duct-like structure with a nearly absent lumen surrounded by fibrosis. Distal to this section, a patent bile duct lumen was identified.


TERMINOLOGY


Abbreviations




• Biliary atresia (BA)


Synonyms




• Extrahepatic biliary atresia
image Involves both extrahepatic and intrahepatic biliary tree

– Thus, best classified simply as BA


Definitions




• Idiopathic fibroinflammatory process that destroys bile ducts
image May culminate in ductopenia and biliary cirrhosis


ETIOLOGY/PATHOGENESIS


Idiopathic




• Probable multiple disease mechanisms
image Possible roles for viral infection, genetic factors, congenital malformations

image Associated genetic/chromosomal abnormalities

– Trisomy 18 and 21

– Cateye and Kabuki syndromes


CLINICAL ISSUES


Epidemiology




• Incidence
image 1:5,000 to 1:19,000 newborns

image Most common in East Asian countries


Presentation




• Most common cause of pathologic infant jaundice
• Clinical triad

image Persistent neonatal jaundice, beyond 2 weeks of life

image Dark urine and acholic pale stools

image Hepatomegaly

• Associated extrahepatic congenital anomalies present in up to 20% of cases
image Most common is biliary atresia splenic malformation syndrome

• 2 general clinical patterns
image Prenatal, embryonal/fetal, congenital, or early form
– 15-35% of cases

– Low birth weight, jaundice at birth

image Perinatal, postnatal, infantile, acquired, or late form
– 65-85% of cases

– Healthy anicteric, average-weight neonates

– Jaundice usually presents after 2 weeks of age


Laboratory Tests




• Similar to other forms of neonatal cholestasis
image Conjugated hyperbilirubinemia

image Variably elevated alkaline phosphatase

image Variably elevated transaminases

image γ-glutamyl transpeptidase typically > 200 U/L


Treatment




• Surgery
image Hepatoportoenterostomy (Kasai procedure)

– Palliative procedure to reestablish some bile flow

– Best if performed before 45-60 days of age

image Liver transplantation

– Biliary atresia most frequent indication for pediatric liver transplantation

– For infants without bile drainage procedure, transplant within 6 months to 2 years of age

Apr 20, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Biliary Atresia
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