Overview
Definition:
Kasai portoenterostomy is a surgical procedure performed in infants diagnosed with biliary atresia
It involves excising the fibrotic remnant of the extrahepatic bile ducts and creating a Roux-en-Y anastomosis between the porta hepatis and a loop of jejunum
The aim is to restore bile flow from the liver to the intestine, preventing further liver damage and potentially preserving native liver function.
Epidemiology:
Biliary atresia is the most common cause of neonatal cholestasis requiring surgical intervention, occurring in approximately 1 in 10,000 to 1 in 20,000 live births worldwide
It is more prevalent in East Asian populations
Early diagnosis and surgical intervention are crucial for favorable outcomes
Approximately 20-30% of infants with biliary atresia have associated anomalies like polysplenia syndrome, intestinal malrotation, or cardiac defects.
Clinical Significance:
Biliary atresia is a progressive, obliterative disease of the intrahepatic and extrahepatic bile ducts
Without timely treatment, it leads to irreversible biliary cirrhosis and portal hypertension, invariably resulting in liver failure and the need for liver transplantation
Kasai portoenterostomy is the primary surgical treatment aiming to decompress the biliary system and improve bile drainage
Its success is time-dependent, with significantly better outcomes when performed before 60 days of age.
Clinical Presentation
Symptoms:
Progressive jaundice, typically presenting within the first 2-4 weeks of life
Acholic (pale) stools, indicating lack of bile pigments in the feces
Dark urine, due to conjugated bilirubin excretion
Poor weight gain and failure to thrive
Hepatomegaly, which may be noted on physical examination
Pruritus, which can be severe.
Signs:
Jaundice, initially scleral icterus, progressing to generalized skin jaundice
Pale, clay-colored stools
Enlarged and firm liver (hepatomegaly)
Splenomegaly, may develop later as portal hypertension progresses
Ascites, indicating decompensated liver disease.
Diagnostic Criteria:
Diagnosis is based on a combination of clinical presentation, laboratory investigations, and imaging
Persistent conjugated hyperbilirubinemia (total bilirubin > 1 mg/dL, with conjugated bilirubin > 20% of total) is a key laboratory finding
Absence of bile ducts on imaging modalities like ultrasound or cholangiography, and a characteristic liver biopsy showing portal tract fibrosis and bile duct proliferation are diagnostic.
Diagnostic Approach
History Taking:
Detailed birth history, including gestational age and any perinatal complications
Onset and progression of jaundice
Character of stool color (asking parents about presence of color)
History of any vomiting or feeding difficulties
Family history of liver disease or genetic conditions
Any associated congenital anomalies identified at birth.
Physical Examination:
Assess for jaundice, noting extent and progression
Palpate the abdomen carefully for hepatomegaly and splenomegaly
Assess for ascites by checking for fluid thrill and shifting dullness
Examine for any obvious external congenital anomalies
Assess overall infant well-being, hydration, and nutritional status.
Investigations:
Complete blood count (CBC) to rule out infection
Liver function tests (LFTs): elevated alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT) are characteristic
elevated conjugated bilirubin is the hallmark
Prothrombin time (PT) and activated partial thromboplastin time (aPTT) to assess synthetic function
Viral serologies (Hepatitis A, B, E, CMV, EBV) to rule out other causes of hepatitis
Ultrasound abdomen: may show absent gallbladder or a triangular cord sign at the porta hepatis
can assess for liver size and presence of ascites
HIDA scan (cholescintigraphy): assess bile flow into the duodenum
absent or minimal intestinal excretion indicates biliary obstruction
Liver biopsy: essential for diagnosis
shows portal tract inflammation and fibrosis, bile ductular proliferation, and absence of normal bile ducts
Cholangiography (intraoperative): gold standard to confirm diagnosis and assess the extent of biliary atresia.
Differential Diagnosis:
Other causes of neonatal cholestasis: neonatal hepatitis, genetic disorders (e.g., Alagille syndrome, alpha-1 antitrypsin deficiency), metabolic disorders (e.g., galactosemia, tyrosinemia), choledochal cyst, sepsis
Differentiating biliary atresia relies on the combination of persistent conjugated hyperbilirubinemia, acholic stools, and characteristic findings on imaging and liver biopsy.
Management
Indications:
Confirmed diagnosis of biliary atresia on imaging and/or liver biopsy
Ideally performed before 60 days of age for optimal outcome
Patients with Kasai portoenterostomy have a significantly better chance of native liver survival than those treated later or only with transplantation.
Surgical Management:
The Kasai procedure involves several key steps: 1
Laparotomy and exploration to confirm biliary atresia and rule out other pathologies
2
Excision of the fibrotic remnant of the extrahepatic bile ducts at the porta hepatis, ensuring clear dissection to the hilum
3
Creation of a Roux-en-Y jejunal loop, which is then anastomosed to the porta hepatis
This allows bile to drain from the liver directly into the jejunum
Often, a T-tube is placed in the jejunal limb to maintain patency and facilitate postoperative cholangiography if needed
Postoperative antibiotics are crucial to prevent ascending cholangitis
Vitamin K supplementation is standard.
Supportive Care:
Nutritional support is critical, as malabsorption of fat-soluble vitamins (A, D, E, K) is common
Parenteral or enteral feeding may be necessary
Monitoring for signs of cholangitis (fever, jaundice, abdominal pain) is essential
Regular LFT monitoring to assess bile flow and liver function
Follow-up with a pediatric gastroenterologist and surgeon is lifelong.
Complications
Early Complications:
Bleeding from the porta hepatis during dissection
Bile leak from the anastomosis
Cholangitis, an infection of the bile ducts, presenting with fever, abdominal pain, and worsening jaundice
Wound infection
Ileus
Small bowel obstruction due to adhesions or internal hernia.
Late Complications:
Cholangitis remains a significant long-term complication, even years after surgery
Progressive biliary cirrhosis and portal hypertension leading to liver failure
Development of esophageal varices and gastrointestinal bleeding
Ascites
Liver transplantation may eventually be required if native liver function deteriorates.
Prevention Strategies:
Meticulous surgical technique with careful dissection at the porta hepatis to minimize bleeding and bile leak
Prompt recognition and treatment of cholangitis with broad-spectrum antibiotics
Adequate nutritional support to optimize general health
Regular postoperative monitoring of LFTs and clinical status.
Prognosis
Factors Affecting Prognosis:
Age at surgery is the most critical factor
patients operated on before 60 days have a significantly higher success rate
Complete or near-complete restoration of bile flow after surgery
Absence of significant associated congenital anomalies
The presence and extent of intrahepatic bile ducts at the time of surgery
Successful management of complications like cholangitis.
Outcomes:
Approximately 40-60% of patients undergoing Kasai portoenterostomy may achieve good bile drainage and maintain native liver function for several years
However, many will eventually develop cirrhosis and require liver transplantation
Survival with native liver is highly dependent on early diagnosis and successful surgery
Successful surgery is defined by passage of bile into the stool and gradual decrease in jaundice.
Follow Up:
Lifelong follow-up is required
This includes regular clinical assessments, serial LFTs, and monitoring for complications of chronic liver disease such as portal hypertension and varices
Imaging like abdominal ultrasound for liver size, spleen size, and ascites assessment
Upper GI endoscopy to screen for esophageal varices
Ultimately, referral for liver transplantation evaluation is necessary if native liver function declines.
Key Points
Exam Focus:
Kasai portoenterostomy is the surgical treatment for biliary atresia
Perform before 60 days of age for best outcome
Key steps: excision of fibrotic remnant, Roux-en-Y jejunojejunostomy to porta hepatis
Complications include cholangitis and progressive cirrhosis
Definitive diagnosis often requires liver biopsy and intraoperative cholangiography
Ultrasound finding of triangular cord sign is suggestive
HIDA scan shows absent intestinal excretion.
Clinical Pearls:
Suspect biliary atresia in any infant with prolonged conjugated jaundice
Consult pediatric surgery early
Postoperative cholangitis is common
educate parents on recognizing symptoms (fever, dark urine, pale stools)
Vitamin K supplementation is essential preoperatively and postoperatively
Monitor for signs of portal hypertension even in patients with good bile drainage.
Common Mistakes:
Delaying surgical intervention beyond the optimal window (60 days)
Incomplete dissection of the fibrotic remnants at the porta hepatis
Failure to manage cholangitis promptly and aggressively
Inadequate nutritional support postoperatively
Not recognizing the need for long-term follow-up and potential liver transplantation.