Overview
Definition:
Choledochal cysts are congenital, saccular or fusiform dilatations of the bile ducts, typically involving the extrahepatic bile ducts or both extrahepatic and intrahepatic ducts
Excision with hepaticojejunostomy is the definitive surgical treatment to remove the cyst and reconstruct the biliary enteric continuity, aiming to prevent complications such as cholangitis, pancreatitis, choledocholithiasis, and malignant transformation.
Epidemiology:
Choledochal cysts are rare, with an incidence of 1 in 100,000 to 1 in 150,000 live births in Western populations, but more common in Asian countries, particularly Japan and Korea (1 in 10,000 to 1 in 20,000)
They are more common in females (3:1 to 4:1 ratio)
The peak incidence is in children, but they can present at any age.
Clinical Significance:
Choledochal cysts represent a significant congenital anomaly with a high risk of life-threatening complications if left untreated
Early diagnosis and surgical intervention are crucial to prevent morbidity and mortality, especially the risk of cholangiocarcinoma, which is significantly elevated in untreated or inadequately treated patients.
Clinical Presentation
Symptoms:
The classic triad of abdominal pain, jaundice, and an abdominal mass is present in less than 30% of patients
More commonly, patients present with intermittent or persistent abdominal pain
Jaundice may be intermittent or progressive
Vomiting and fever may indicate associated cholangitis
Children often present with failure to thrive or recurrent abdominal pain
Pancreatitis can manifest as severe epigastric pain radiating to the back.
Signs:
Physical examination may reveal a palpable, non-tender abdominal mass, particularly in the right upper quadrant or epigastrium
Icterus of the sclera and skin is evident in jaundiced patients
Hepatomegaly can be present due to biliary obstruction or secondary biliary cirrhosis
Signs of cholangitis, such as fever and right upper quadrant tenderness (Murphy's sign), may be observed.
Diagnostic Criteria:
Diagnosis is primarily based on characteristic imaging findings, typically confirmed by ultrasonography, CT scan, MRCP, and ERCP
The International Classification of Hepatobiliary Malignant Tumors (Todani classification) is widely used to categorize choledochal cysts based on their location and morphology, which guides surgical management.
Diagnostic Approach
History Taking:
A detailed history focusing on the duration and character of abdominal pain, presence and pattern of jaundice, episodes of fever or chills suggestive of cholangitis, and any episodes of pancreatitis
Ask about family history of congenital anomalies or biliary disease
In infants, inquire about feeding difficulties and failure to thrive.
Physical Examination:
A thorough abdominal examination, including palpation for masses, assessment for tenderness, and evaluation for hepatomegaly or splenomegaly
Examination for icterus of sclera and skin, and assessment of vital signs to detect fever or signs of sepsis.
Investigations:
Initial investigations include liver function tests (LFTs), which may show elevated bilirubin, alkaline phosphatase, and gamma-glutamyl transferase (GGT)
Amylase and lipase levels are important to rule out pancreatitis
Imaging modalities are crucial: Ultrasound is usually the first-line investigation
CT scan provides better anatomical detail
MRCP (Magnetic Resonance Cholangiopancreatography) is the gold standard for delineating the biliary tree and identifying associated anomalies, without radiation or contrast concerns for patients with renal insufficiency
ERCP (Endoscopic Retrograde Cholangiopancreatography) can be diagnostic and therapeutic but carries risks like pancreatitis and perforation.
Differential Diagnosis:
Conditions to consider include simple choledochal dilatation, Caroli's disease (type V choledochal cyst with intrahepatic ductal dilatation), choledocholithiasis, parasitic infestations of the bile duct, choledochal duplication, and pseudocysts of the pancreas
Distinguishing features are based on the characteristic saccular or fusiform dilatation of the extrahepatic bile ducts.
Management
Initial Management:
Management of acute complications such as cholangitis or pancreatitis is paramount
This may involve intravenous antibiotics, fluid resuscitation, pain control, and endoscopic drainage if necessary
Nutritional support should be initiated.
Medical Management:
Medical management is primarily supportive and involves antibiotics for cholangitis, analgesics for pain, and specific treatment for pancreatitis
There is no medical cure for choledochal cysts
surgery is the definitive treatment.
Surgical Management:
Complete excision of the extrahepatic bile duct cyst is the gold standard surgical treatment
This is typically followed by Roux-en-Y hepaticojejunostomy to restore biliary enteric continuity and prevent bile stasis
The extent of resection should include the entire extrahepatic bile duct up to the confluence of the hepatic ducts
Intrahepatic involvement requires separate consideration, with segmentectomy or lobectomy sometimes necessary for profoundly involved segments
The Todani classification guides the extent of resection
Follow-up after surgery is essential to monitor for complications and malignant transformation.
Supportive Care:
Postoperative care includes meticulous fluid management, pain control, and monitoring for signs of anastomotic leak or biliary obstruction
Nutritional assessment and support are important
Prophylactic antibiotics may be continued
Early mobilization and pulmonary physiotherapy are encouraged.
Complications
Early Complications:
Bleeding from the surgical site
Biliary leak from the hepaticojejunostomy or liver bed
Cholangitis due to inadequate drainage or anastomotic stricture
Pancreatitis from duodenogastric reflux or injury to the pancreatic duct
Wound infection
Ileus.
Late Complications:
Anastomotic stricture leading to secondary biliary cirrhosis and cholangitis
Recurrent cholangitis
Gallstone formation in the remnant bile duct or jejunum
Development of cholangiocarcinoma, which is the most serious long-term complication, occurring in a significant percentage of patients even after surgical excision if residual cyst wall is left behind or intrahepatic ducts are extensively involved.
Prevention Strategies:
Complete and careful excision of the entire cyst wall, including meticulous dissection at the pancreaticobiliary junction, is crucial to prevent cholangiocarcinoma
Adequate drainage of the biliary system with a wide hepaticojejunostomy, and ensuring no residual cyst remnants are left, are key preventive measures
Careful intraoperative cholangiography can identify critical anatomical variations and ensure complete resection.
Prognosis
Factors Affecting Prognosis:
The prognosis is generally excellent with complete surgical excision, especially when performed at a young age before complications arise
Factors influencing prognosis include the type of choledochal cyst (Todani classification), age at diagnosis and surgery, completeness of excision, presence of associated anomalies, and the development of cholangiocarcinoma.
Outcomes:
With successful surgical management, patients can expect a normal life expectancy
However, lifelong surveillance is recommended due to the risk of cholangiocarcinoma
Symptom recurrence or development of complications like cholangitis or stricture may require re-intervention.
Follow Up:
Long-term follow-up is essential, typically involving annual clinical examinations and LFTs
Imaging studies such as ultrasound or MRCP may be performed periodically to monitor for anastomotic complications, bile duct stones, and importantly, to screen for cholangiocarcinoma
Patient education regarding symptoms of cholangitis or malignancy is also important.
Key Points
Exam Focus:
Remember the Todani classification of choledochal cysts
Complete excision of the extrahepatic bile duct is mandatory
Hepaticojejunostomy (Roux-en-Y) is the reconstruction of choice
The risk of cholangiocarcinoma is a critical concern, even after surgery.
Clinical Pearls:
Suspect choledochal cyst in any child or young adult with unexplained abdominal pain, jaundice, or pancreatitis
Always consider MRCP as the primary imaging modality for detailed biliary anatomy
Be vigilant for cholangitis symptoms post-operatively.
Common Mistakes:
Incomplete excision of the cyst wall, leading to increased risk of malignancy
Inadequate reconstruction of the hepaticojejunostomy, leading to strictures
Failure to adequately screen for cholangiocarcinoma in long-term follow-up
Misinterpreting imaging findings, leading to delayed diagnosis or suboptimal treatment.