Overview
Biliary Atresia
1. Clinical Overview
Summary
Biliary atresia (BA) is a progressive, idiopathic, fibro-obliterative disease of the extrahepatic bile ducts that presents in neonates. It is the most common cause of neonatal cholestasis requiring surgery and the leading indication for paediatric liver transplantation. Early diagnosis is critical because the Kasai portoenterostomy — the primary surgical treatment — has significantly better outcomes if performed before 60 days of age. Delays in diagnosis lead to progressive fibrosis, cirrhosis, and liver failure. The key clinical features are prolonged conjugated jaundice, pale (acholic) stools, dark urine, and hepatomegaly.
Key Facts
- Incidence: 1 in 10,000-18,000 live births (UK: ~50 cases/year)
- Timing: Presents in first 2-8 weeks of life
- Key feature: Conjugated hyperbilirubinaemia + pale stools
- Surgical window: Kasai should be performed before 60 days for best outcomes
- Transplant rate: ~50% require liver transplant by age 2 if Kasai fails
- Most common indication: Paediatric liver transplantation
Clinical Pearls
The 14-Day Rule: Any term infant jaundiced beyond 14 days requires a split bilirubin. Conjugated jaundice is never normal and demands urgent investigation.
Stool Colour Is Key: Pale (clay, putty, or chalk-coloured) stools indicate biliary obstruction. Use stool colour charts for parents.
Time Is Liver: Kasai success rate drops from 80% at less than 30 days to less than 20% after 90 days. Urgent referral to a specialist centre is essential.
Why This Matters Clinically
Biliary atresia is a surgical emergency with a narrow window for successful intervention. Delayed diagnosis is common and leads to irreversible liver damage. Every clinician seeing neonates must recognise the warning signs and act promptly.
2. Epidemiology
Incidence & Prevalence
- Incidence: 1 in 10,000-18,000 live births
- UK: ~50 new cases per year
- Asia-Pacific: Higher incidence (1 in 5,000 in Taiwan)
Demographics
| Factor | Details |
|---|---|
| Sex | Slight female predominance |
| Ethnicity | Higher in Asian populations |
| Seasonality | Some studies suggest clustering |
| Associated anomalies | 10-20% have Biliary Atresia Splenic Malformation (BASM) |
Classification
| Type | Frequency | Features |
|---|---|---|
| Isolated (perinatal) | 80-85% | No other anomalies |
| Syndromic (embryonic/fetal) | 15-20% | BASM: polysplenia, situs inversus, cardiac defects |
3. Pathophysiology
Mechanism
Step 1: Unknown Insult
- Probable viral, immune, or developmental trigger
- Perinatal infection (?reovirus, CMV, rotavirus) implicated but not proven
Step 2: Inflammatory Fibrosis
- Progressive inflammatory destruction of extrahepatic bile ducts
- Fibrous obliteration of biliary tree
Step 3: Cholestasis
- Bile cannot drain from liver to duodenum
- Conjugated bilirubin accumulates
- Bile acids damage hepatocytes
Step 4: Progressive Liver Injury
- Ongoing cholestasis causes hepatic fibrosis
- Leads to cirrhosis, portal hypertension, liver failure
Anatomy
| Level of Atresia | Frequency | Kasai Outcome |
|---|---|---|
| Type I (Common bile duct only) | 5% | Better |
| Type II (Common hepatic duct) | 2% | Better |
| Type III (Porta hepatis — most proximal) | 90% | Worse |
4. Clinical Presentation
Symptoms
Signs
Red Flags
[!CAUTION] Red Flags — Urgent specialist referral if:
- Jaundice beyond 14 days (term) or 21 days (preterm)
- Pale stools at any age
- Dark urine in a jaundiced neonate
- Hepatomegaly
- Conjugated bilirubin greater than 20% of total or greater than 25 μmol/L
Jaundice persisting beyond 2 weeks of age
Common presentation.
Pale (acholic) stools — clay, putty, or chalk-coloured
Common presentation.
Dark urine (conjugated bilirubin)
Common presentation.
Poor feeding (late)
Common presentation.
Failure to thrive (late)
Common presentation.
5. Clinical Examination
Structured Approach
General:
- Jaundice (yellow sclera, skin)
- Nutritional status
Abdomen:
- Hepatomegaly (firm, smooth or nodular)
- Splenomegaly (portal hypertension)
- Ascites (late sign)
Skin:
- Bruising (coagulopathy)
- Xanthomas (late)
Other:
- Cardiac murmur (associated anomalies in BASM)
- Polysplenia/situs inversus (syndromic BA)
6. Investigations
First-Line
| Test | Purpose | Finding in BA |
|---|---|---|
| Split bilirubin | Distinguish conjugated from unconjugated | Conjugated greater than 20% or greater than 25 μmol/L |
| LFTs | Liver function, cholestasis | Elevated GGT, ALP; transaminases variable |
| Coagulation | Vitamin K deficiency | Prolonged PT/INR |
| Stool colour | Acholic stools | Pale/clay coloured |
| Urine dipstick | Conjugated bilirubin | Bilirubin present |
Second-Line / Specialist
| Test | Purpose | Findings |
|---|---|---|
| Abdominal ultrasound | Triangular cord sign; absent gallbladder | "Triangular cord" at porta hepatis; gallbladder absent or abnormal |
| HIDA scan (hepatobiliary scintigraphy) | Assess biliary excretion | No excretion to bowel (non-specific) |
| Liver biopsy | Gold standard for diagnosis | Bile duct proliferation, portal fibrosis, bile plugs |
| Intraoperative cholangiogram | Confirm diagnosis at surgery | Atretic biliary tree |
Differential Diagnosis
| Condition | Features |
|---|---|
| Neonatal hepatitis | Similar biochemistry; gallbladder present |
| Alpha-1 antitrypsin deficiency | Low A1AT, liver biopsy PAS-positive inclusions |
| Alagille syndrome | Dysmorphic features, cardiac, vertebral anomalies |
| Choledochal cyst | Cystic dilatation on USS |
| Inspissated bile syndrome | TPN-related; may resolve |
7. Management
Management Algorithm
PROLONGED NEONATAL JAUNDICE
↓
┌────────────────────────────────────────┐
│ 1. Split Bilirubin │
│ - Conjugated >20% or >25 μmol/L? │
│ - YES → Urgent investigation │
└────────────────────────────────────────┘
↓
┌────────────────────────────────────────┐
│ 2. Stool Colour + USS │
│ - Pale stools? │
│ - Triangular cord sign? │
│ - Absent gallbladder? │
└────────────────────────────────────────┘
↓
┌────────────────────────────────────────┐
│ 3. Specialist Centre Referral │
│ - Liver biopsy │
│ - Intraoperative cholangiogram │
│ - CONFIRM DIAGNOSIS │
└────────────────────────────────────────┘
↓
┌────────────────────────────────────────┐
│ 4. Kasai Portoenterostomy │
│ - Aim <30 days for best outcome │
│ - Must be <60 days │
│ - Specialised centre only │
└────────────────────────────────────────┘
↓
┌────────────────────────────────────────┐
│ 5. Post-Kasai Care │
│ - Antibiotics (cholangitis │
│ prophylaxis) │
│ - Ursodeoxycholic acid │
│ - Fat-soluble vitamins (A, D, E, K)│
│ - Nutritional support │
└────────────────────────────────────────┘
↓
┌────────────────────────────────────────┐
│ 6. Liver Transplant │
│ - If Kasai fails │
│ - Progressive liver disease │
│ - ~50% by age 2 │
└────────────────────────────────────────┘
Kasai Portoenterostomy (Hepatoportoenterostomy)
Procedure:
- Excision of fibrous biliary remnant
- Roux-en-Y jejunal loop anastomosed to porta hepatis
- Allows bile drainage from intrahepatic ducts
Success Factors:
- Age at surgery (best if less than 30 days)
- Centre experience
- Post-operative care
Outcomes:
- less than 30 days: ~80% clearance of jaundice
- 30-60 days: ~50%
- greater than 90 days: less than 20%
Post-Operative Care
| Intervention | Purpose |
|---|---|
| Prophylactic antibiotics | Prevent ascending cholangitis |
| Ursodeoxycholic acid | Promote bile flow |
| Fat-soluble vitamins | Prevent deficiency (A, D, E, K) |
| MCT-enriched formula | Improve fat absorption |
| Regular monitoring | LFTs, growth, nutritional status |
Liver Transplantation
Indications:
- Failed Kasai (progressive jaundice/cholangitis)
- Cirrhosis and portal hypertension
- Liver failure
- Growth failure despite nutritional support
Outcomes:
- 5-year survival post-transplant: greater than 90%
8. Complications
Early
| Complication | Management |
|---|---|
| Ascending cholangitis | IV antibiotics; recurrent = poor prognosis |
| Coagulopathy | Vitamin K |
| Nutritional deficiency | Fat-soluble vitamins, MCT formula |
Late
| Complication | Details |
|---|---|
| Cirrhosis | Progressive despite Kasai |
| Portal hypertension | Varices, splenomegaly, ascites |
| Hepatopulmonary syndrome | Hypoxia, platypnoea |
| Growth failure | Chronic liver disease |
| Hepatocellular carcinoma | Rare; surveillance in cirrhosis |
9. Prognosis & Outcomes
Outcomes
| Variable | Outcome |
|---|---|
| Kasai success (jaundice clearance) | 50-60% overall |
| Kasai less than 30 days | ~80% success |
| Kasai greater than 90 days | less than 20% success |
| Native liver survival at 5 years | ~50% |
| Transplant-free survival at 20 years | ~40% |
| Post-transplant 5-year survival | greater than 90% |
Prognostic Factors
| Good Prognosis | Poor Prognosis |
|---|---|
| Early surgery (less than 30 days) | Late diagnosis (greater than 60 days) |
| Clearance of jaundice post-Kasai | Persistent jaundice |
| No cholangitis | Recurrent cholangitis |
| Type I/II BA | Type III BA |
| Experienced centre | Inexperienced centre |
10. Evidence & Guidelines
Key Guidelines
- NICE Neonatal Jaundice (CG98) — Screening for conjugated jaundice.
- BSPGHAN/BASL Guidelines on Biliary Atresia — UK pathway.
- Japanese Biliary Atresia Society Guidelines — Management protocols.
Key Evidence
UK Biliary Atresia Registry
- Centralisation of Kasai surgery improved outcomes
- PMID: 16614730
Davenport et al. (2016) — Predictors of native liver survival
- Age at Kasai critical; greater than 100 days = poor outcome
- PMID: 27009920
Evidence Strength
| Intervention | Level | Key Evidence |
|---|---|---|
| Kasai before 60 days | 2a | Registry data, cohort studies |
| Centralisation | 2b | UK outcomes improved |
| Ursodeoxycholic acid | 3 | Case series |
11. Patient/Layperson Explanation
What is Biliary Atresia?
Biliary atresia is a rare liver condition that affects newborn babies. The tubes (bile ducts) that carry bile from the liver to the gut become blocked or damaged. This means bile cannot drain properly, which damages the liver.
What are the warning signs?
- Jaundice (yellow skin and eyes) lasting more than 2 weeks
- Pale or clay-coloured poo
- Dark wee
- A swollen tummy (big liver)
How is it treated?
- Kasai operation: A surgery to create a new path for bile to drain from the liver. Works best if done early (before 60 days old).
- Medications: Antibiotics to prevent infections, vitamins, and medicines to help bile flow.
- Liver transplant: If the Kasai operation doesn't work, your child may need a new liver.
What to expect
- With early treatment, many children do well
- Some children will need a liver transplant
- Children need regular check-ups for life
- Growth and nutrition need careful monitoring
When to seek help
Take your baby to a doctor urgently if:
- Jaundice lasts more than 2 weeks
- Poo is pale or white
- Your baby seems unwell or is not feeding
12. References
Primary Guidelines
- Davenport M. Biliary atresia: clinical aspects. Semin Pediatr Surg. 2012;21(3):175-84. PMID: 22800970
Key Studies
- Davenport M, et al. Biliary atresia: current concepts and research priorities. J Hepatol. 2016;65(5):989-997. PMID: 27009920
- McKiernan PJ, et al. A prospective study of the role of screening for biliary atresia. Arch Dis Child. 2001;84(4):302-7. PMID: 11259226
Further Resources
- Children's Liver Disease Foundation: childliverdisease.org
- Yellow Alert Stool Colour Chart: yellowalert.org
Last Reviewed: 2025-12-24 | MedVellum Editorial Team
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.