Congenital Abnormalities of Liver, Biliary, and Pancreas Flashcards
liver embryology
*liver appears during the 4th week of gestation as diverticulum arising from duodenum
*cranial portion forms parenchymal tissue + bile ducts
*caudal portion forms gallbladder + cystic duct
bile canaliculi embryology
*bile canaliculi are well developed by 6 weeks of gestation
*intrahepatic ducts formed from cell plates derived from hepatic duct and is complete by 12 weeks of gestation
*gallbladder and cystic duct canalize by 8 weeks of gestation
cholestasis
*decrease in bile flow due to:
1. impaired secretion by hepatocytes OR
2. obstruction of bile flow through intra- or extra-hepatic bile ducts
*elevation of serum CONJUGATED bilirubin (> 1.0)
*indicates hepatobiliary dysfunction
*affects approx 1/2500 infants
neonatal cholestasis - ddx
*BILIARY ATRESIA (most common)
*neonatal hepatitis
*infectious hepatitis
*parenteral nutrition-associated liver disease
neonatal cholestasis - staged evaluation
*clinical evaluation: history + PE
*initial labs: LFTs, fractionated bilirubin
*stool color assessment
*synthetic liver function: INR
*bacterial cultures (blood, urine)
*viral serology (TORCH, viral hepatitis, CMV, HIV)
*urine reducing substances
*alpha-1 antitrypsin phenotype
*thyroid function studies
*sweat test/CF gene
*newborn screen
*imaging (US, HIDA scan)
*liver biopsy
biliary atresia - overview
*destructive inflammatory obliterative cholangiopathy
*intra- and extra-hepatic bile ducts are destroyed during neonatal period
*progressive fibrosis occurs rapidly
biliary atresia - epidemiology
*most frequent identifiable cause of obstructive jaundice in the first 3 months of life
*most common indication for liver transplant in children
*1/10,000-20,000 incidence in US
*nonsyndromic (84%)
*syndromic:
-with laterality defect (10%) - situs inversus, malrotation, polysplenia, congenital heart disease
-without laterality defect (6%) - intestinal atresia, cardiac abnormalities
biliary atresia - pathogenesis
*viral infection
*toxins
*genetic bile duct dysmorphogenesis
*chronic inflammatory or autoimmune mediated duct injury
**cholestasis identified soon after birth, suggesting biliary injury occurred BEFORE BIRTH
biliary atresia - clinical features
*acholic stools (pale stools)
*growth failure
*dark urine
*hepatosplenomegaly (abdominal distention)
*jaundice
*direct/conjugated hyperbilirubinemia
*elevated LFTs (AST, ALT, GGT, alk phos)
*low fat-soluble vitamins (ADEK)
biliary atresia - diagnostic steps
- ultrasound - triangular cord sign, ABSENT/SMALL GALLBLADDER, no biliary ductal dilation
- hepatobiliary scintigraphy (HIDA scan)
- intraoperative cholangiogram (GOLD STANDARD) or liver biopsy (portal inflammation/fibrosis, bile duct proliferation and plugs)
biliary atresia - importance of timely diagnosis
EXTREMELY IMPORTANT: time to treatment determines success of procedure (HPE or Kasai)
*no universal screening method
biliary atresia - treatment
*Kasai hepatoportoenterostomy (HPE):
-excise extrahepatic biliary tree
-porta hepatis is transected at the liver capsule to expose remaining ductules
-jejunal Roux loop is anastomosed to cut surface
biliary atresia - prognosis
*majority of patients will require liver transplantation
-primary failure of HPE
-progressive fibrosis -> cirrhosis
-growth failure
-portal HTN complications
*1 year and 5 year survival rates after transplant are really high!
choledochal cysts
*cystic dilation of biliary tree
*incidence about 1 in 100,000
*30% diagnosed before age 1 year
*more common in females
*increased risk of cholangiocarcinoma
*dx = ultrasound
*treatment = surgical resection
pancreas - embryology
*originates as dorsal bud and two ventral buds
*L ventral bud atrophies
*rotation of stomach & duodenum with elongation carries R ventral bud posteriorly
*fusion of R ventral with dorsal bud completes head & uncinate process
annular pancreas - pathogenesis
*hypertrophy of normal pancreatic tissue
*fusion of heterotopic pancreatic rests
*failure of L ventral bud atrophy
*failure of free rotation of R ventral bud
annular pancreas - clinical presentation
*sx may present at any age (2/3 asymptomatic; approx 50% present in pediatric age)
*vomiting
*peptic ulceration
*abdominal pain - pancreatitis
*jaundice - biliary obstruction
*associated with other congenital defects (Down’s syndrome, esophageal/duodenal atresia, imperforate anus, Meckel’s)
annular pancreas - diagnosis
*evidence of duodenal obstruction on plain abdominal film (double bubble effect)
*barium studies demonstrating duodenal filling defect
*CT
*MRCP/ERCP
*laparotomy, if presents with obstruction
annular pancreas - management
*surgical intervention in cases with obstruction
*recommended approach is a bypass operation
-duodenoduodenostomy is preferred
pancreatic agenesis, hypoplasia, and dysplasia
*complete agenesis rare and usually incompatible with life
*clinical manifestations attributable to both exocrine and endocrine pancreatic dysfunction
*associated with other syndromes
ectopic pancreas
*presence of pancreatic tissue lacking anatomic and vascular continuity with the main body of pancreas
*70-90% occurs in upper GI tract, mostly in gastric antrum
*usually incidental finding
pancreatic divisum
*most common congenital pancreatic anomaly (10% of population)
*abnormality resulting from INCOMPLETE FUSION of dorsal and ventral pancreatic ductal systems
*dorsal duct functions as main drainage system but opens into smaller accessory papilla
pancreatic divisum - clinical presentation
*majority are asymptomatic
*may cause recurrent attacks of pancreatitis or chronic epigastric pain (controversial)
*dx: MRCP/ERCP
common channel syndrome (pancreatic duct anomaly)
*anomalous junctions of common bile duct and main pancreatic duct
*the presence of a long common channel with pancreaticobiliary junction located outside of duodenal wall associated with pancreatitis and choledochal cyst
*can lead to abdominal pain, pancreatitis
*dx and management with ERCP
