Biliary Atresia

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Biliary atresia is a rare disease of unknown aetiology which leads to progressive fibrosis and destruction of both the intra- and extra-hepatic biliary duct system with resultant cholestasis, cirrhosis and portal hypertension. Untreated, patients typically die before 2 years of age from hepatic failure.

biliary system diagram


Contents

Incidence + Aetiology

  • Incidence is 1:15 000 live births in the UK (~50 new cases per year).
    • Highest in Asian populations
  • Aetiology: unknown. Probably multifactorial. No evidence for a genetic basis.


Classification and Subtypes

Classification (by extent of biliary damage)

  • Type I Biliary Atresia - Common bile duct + proximal cystic duct
  • Type II Biliary Atresia - Common hepatic duct
  • Type III Biliary Atresia - Whole extra-hepatic biliary tree
    • Most common subtype

Subtypes

  • Perinatal / acquired ~80-90%
  • Embryonic / syndromic ~10-20%
    • Presence of other congenital abnormalities
      • cardiac anomalies (ASD, VSD)
      • Absent inferior vena cava
      • polysplenia
      • situs inversus


Presentation and diagnosis

Diagnosis may be difficult, compounded by the multitude of other causes of Neonatal Jaundice which, together, are common in the neonatal period.


Extra-hepatic causes of jaundice cause conjugated hyperbilirubinaemia with pale stools and dark urine due to obstruction to biliary outflow. Intra-hepatic causes often produce a mixed picture, though often the bilirubin is mainly conjugated, whereas non-hepatic causes often lead to unconjugated hyperbilirubinaemia. A mixed picture may also represent two simultaneous causes, with the non-pathological cause resolving over time.


  • Diagnosis requires clinical suspicion with appropriate further investigation.
    • Liver disease must be excluded in all neonates if jaundice persists beyond 14 days of age.
  • Presentation is uniquely within the neonatal period, though diagnosis may be delayed or missed.
    • Delayed diagnosis severely worsens prognosis.
  • Definitive diagnosis is at laparotomy under direct vision


Clinical Criteria

  • Prolonged jaundice (ie. beyond 14 days age)
  • Plus:
    • Pale stools
    • dark urine
    • Failure to thrive
    • Hepatomegaly

Other presentations:

  • Coagulopathy
  • Abnormal antenatal scan ~5%
  • Splenomegaly / portal hypertension (late signs)


Investigations

  • Liver function tests
    • Conjugated Bilirubin raised >100 umol/L (normal <20 umol/L)
    • Raised Alkaline Phosphatase, ALP >600 iu/L (normal <500 iu/L)
    • Gamma GT >100 IU/L (normal 20-40).
    • Albumin + Coagulation: usually normal at presentation
  • Abdominal Ultrasound
    • Hepatomegaly
    • Absent / contracted gallbladder after 4 hour fast
  • HIDA or TEBIDA (N-tert-butyliminodiacetic acid + phenobarbitone pre-treatment 3-5 days) hepatobiliary scanning
    • Good hepatic uptake, reduced / absent excretion to intestine.
  • Percutaneous liver biopsy
    • Portal fibrosis
    • Cholestasis
    • Biliary duct proliferation

Differential Diagnoses


Management

Surgical

Management is surgical, aiming to restore biliary flow. Surgery before 8 weeks of age is a current target.

  • A Kasai Portoenterostomy is performed, which involves resecting the biliary tree and forming a Roux Loop (also known as 'Roux-en-Y') which is anastamosed to the cut surface of the liver at the former origin of the extra-hepatic biliary tree.
  • Liver Transplantation must also be considered. Indications include:
    • Failure to establish biliary drainage with the Kasai Proceedure (ie Unsuccessful)
    • Successful Kasai proceedure with:
      • Development of cirrhosis with hepatic failure
      • Portal hypertension with ascites and variceal bleeding uncontrolled by endoscopy
      • Progressive or persistent cholestasis


Post operative / Medical

Multidisciplinary Team nutritional and emotional support

  • Antibiotics: IV then oral prophylaxis
  • Ursodeoxycholic acid
  • Oral fat soluble vitamin supplement
  • High calorie feed supplementation


Complications

  • All usual general complications of surgery (immediate, early and late).
  • Specific complications
    • Immediate: biliary leaks, ascending cholangitis, worsened ascites
    • Later: malabsorption / malnutrition / vitamin deficiency (fat soluble) with associated complications


Prognosis

Biliary Atresia is progressive: untreated patients usually die before 2 years of age from hepatic failure.


Success of surgery has been shown to be significantly affected by age at surgery. <30 days age provides clear advantage, and >90 days age significantly poorer outcomes.

  • From the British Paediatric Surveillance Unit (BPSU) study 1993-1995: Median age at referral = 40 days


Three studies, including the above mentioned BPSU study demonstrated clear advantage of an experienced surgeon and surgical centre, resulting in a Department of Health directive in 1999 that all infants with suspected biliary atresia be referred to only three centres in the UK who would perform the Kasai Proceedure and provide liver transplantation if necessary.

  1. Kings College Hospital, London
  2. St James' Hospital, Leeds
  3. Birmingham Children's Hospital


  • Where the Kasai Proceedure is successful, 80% have their own liver at 10 years with a good quality of life.
  • Elective Liver Transplantation
    • 1 year survival: 95%
    • 10 year survival (USA): 86%


Screening

Early diagnosis and treatment is essential.

  • Dried blood spot; bile acid screening : no benefit
  • Conjugated Bilirubin at 6-10 days: sensitive and specific for liver disease
    • Liquid testing only at present. Dried spot testing required.
  • Stool colour charts: benefit in some countries. See 'Yellow Alert Campaign'.


Yellow Alert Campaign

Awareness campaigns both within the medical profession and public domain have produced significant improvements in outcome.
CLDF Yellow Alert


The Children's Liver Foundation launched the 'Yellow Alert' Campaign to promote awareness. A useful protocol for investigating neonatal jaundice can be found on their website (References).

References

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