Overview
Definition:
Choledochal cysts are congenital dilations of the biliary tree
They are rare, and pediatric cases often present with complications
Excision and reconstruction are the definitive treatments to prevent malignancy and manage complications.
Epidemiology:
Incidence is estimated at 1 in 100,000 to 1 in 150,000 live births
More common in females and Asian populations
They represent approximately 5% of all pediatric bile duct dilatations.
Clinical Significance:
Choledochal cysts are significant due to their association with cholangiocarcinoma, pancreatitis, recurrent cholangitis, biliary lithiasis, and potential for liver cirrhosis and portal hypertension
Early diagnosis and surgical management are crucial for optimal outcomes.
Clinical Presentation
Symptoms:
The classic triad of jaundice, abdominal pain, and a palpable abdominal mass is present in less than 30% of pediatric patients
More commonly, infants present with conjugated hyperbilirubinemia, acholic stools, and dark urine
Older children may exhibit intermittent jaundice, right upper quadrant pain, nausea, vomiting, and failure to thrive.
Signs:
Hepatomegaly and an enlarged, distended gallbladder may be palpable
Tenderness in the right upper quadrant
Icterus of sclera and skin
Fever may indicate cholangitis.
Diagnostic Criteria:
Diagnosis is based on characteristic imaging findings, often supplemented by intraoperative cholangiography
Todani classification is widely used to categorize choledochal cysts based on their location and morphology.
Diagnostic Approach
History Taking:
Detailed birth history, feeding history, and onset of jaundice
Any episodes of fever, abdominal pain, or vomiting
Family history of biliary anomalies or GI issues
Recent travel or exposure to infections is less relevant for congenital cysts.
Physical Examination:
Thorough abdominal examination, assessing for hepatosplenomegaly, masses, and tenderness
Evaluation for jaundice and hydration status
Cardiopulmonary assessment to evaluate for any systemic involvement.
Investigations:
Laboratory: Complete blood count (CBC), liver function tests (LFTs) including total and direct bilirubin, AST, ALT, alkaline phosphatase, GGT, and amylase/lipase to rule out pancreatitis
Imaging: Ultrasound (US) is the initial modality of choice, revealing cystic dilation of the common bile duct
MRCP (Magnetic Resonance Cholangiopancreatography) provides detailed anatomical information and is highly sensitive
CT scan can also be used
Endoscopic retrograde cholangiopancreatography (ERCP) is less commonly used in pediatrics due to invasiveness but may be considered in specific scenarios.
Differential Diagnosis:
Other causes of conjugated hyperbilirubinemia in infants, such as biliary atresia, neonatal hepatitis, and sepsis
In older children, differential diagnoses include choledocholithiasis, other cystic liver lesions, and pancreatic pseudocysts.
Management
Initial Management:
For symptomatic patients, initial management may involve fluid resuscitation, correction of electrolyte imbalances, and broad-spectrum antibiotics if cholangitis is suspected
Nutritional support is also critical.
Medical Management:
Antibiotics are used to treat cholangitis
Ursodeoxycholic acid (UDCA) may be used to improve bile flow and reduce inflammation in some cases, but it is not curative
Management is primarily surgical.
Surgical Management:
The gold standard treatment is complete excision of the choledochal cyst with hepaticojejunostomy (Roux-en-Y reconstruction)
This is crucial to reduce the risk of malignancy
Indications include symptomatic cysts, cysts >2cm, or those associated with anomalous pancreaticobiliary junction (APBJ)
Laparoscopic techniques are increasingly being adopted.
Supportive Care:
Postoperative care involves close monitoring of fluid balance, pain management, and nutritional support
Parenteral nutrition may be required initially
Monitoring for signs of infection, bile leaks, or stricture formation is vital.
Complications
Early Complications:
Bile leak from the hepaticojejunostomy, intra-abdominal abscess, pancreatitis, cholangitis, bleeding.
Late Complications:
Bile duct stricture, liver cirrhosis, portal hypertension, cholangiocarcinoma (even after complete excision, especially with significant residual fibrosis or APBJ).
Prevention Strategies:
Meticulous surgical technique during excision and reconstruction, ensuring complete removal of the cyst lining, and careful handling of the hepaticojejunostomy
Long-term surveillance for malignancy is essential.
Prognosis
Factors Affecting Prognosis:
Age at diagnosis and treatment, completeness of cyst excision, presence of associated anomalies like APBJ, development of cholangitis or pancreatitis prior to surgery, and the development of cholangiocarcinoma.
Outcomes:
With complete excision and reconstruction, outcomes are generally good, with relief of symptoms and prevention of further complications
Long-term survival is high, but surveillance is mandatory due to the persistent risk of malignancy.
Follow Up:
Lifelong follow-up is recommended, typically involving annual clinical examinations, LFTs, and abdominal ultrasound
MRCP may be used periodically to assess the patency of the biliary reconstruction and rule out strictures
Endoscopic surveillance may be considered in high-risk individuals.
Key Points
Exam Focus:
Todani classification of choledochal cysts is a key area for exams
The high association with cholangiocarcinoma and the principle of complete excision are critical
Understanding the role of MRCP in diagnosis is important
Roux-en-Y hepaticojejunostomy is the standard reconstruction.
Clinical Pearls:
Suspect choledochal cyst in any infant with prolonged conjugated jaundice not attributable to biliary atresia
Do not hesitate to use MRCP for definitive anatomical assessment
Early referral to a pediatric surgeon is paramount
Long-term surveillance is non-negotiable.
Common Mistakes:
Incomplete excision of the cyst lining leading to recurrence or malignancy
Failure to adequately investigate for associated anomalies like APBJ
Delaying surgical intervention, leading to complications like cholangitis or liver damage
Neglecting long-term oncological surveillance.