Choledochal Malformations Flashcards
What is the new term used for choledochal cysts?
The new term used for choledochal cysts is “Choledochal Malformations” (CMs), as it includes a spectrum of malformations and not all dilations are cystic.
What is the definition of choledochal malformations (CMs)?
Choledochal malformations are congenital dilatations of the bile ducts causing biliary stasis and obstruction.
What are the common geographic areas with the highest incidence of choledochal malformations?
Choledochal malformations have their highest incidence in Vietnam and China, although the reasons for this are unclear.
What are some differential diagnoses for cystic swelling in or adjacent to the liver?
Differential diagnoses for cystic swelling in or adjacent to the liver include:
• Cystic biliary atresia
• Echinococcus cyst (usually in children >2-5 years, check serology)
• Pancreatic pseudocyst (usually with a history of trauma 4-6 weeks previously)
• Duplication cyst (e.g., gastric, with ultrasound findings of two layers of mucosa)
• Biliary tumors, such as cystadenoma (rare)
What are some differential diagnoses for cystic swelling near the liver?
• Cystic biliary atresia
• Echinococcus cyst
• Pancreatic pseudocyst
• Duplication cyst
• Biliary tumor (e.g., cystadenoma)
What age group is typically affected by echinococcus cysts?
Echinococcus cysts usually affect children older than 2-5 years.
What is a common history feature of a pancreatic pseudocyst?
A pancreatic pseudocyst typically has a history of trauma 4-6 weeks prior.
What is the debate about the cause of choledochal malformations (CM)?
One theory suggests that distal obstruction of the bile duct, due to malunion of the pancreatic and biliary duct, causes raised pressure, resulting in dilatation. Another theory posits that bile reflux leads to inflammation, weakening the bile duct wall and causing dilatation.
What does the Kings College London classification of choledochal malformations (CM) aim to do?
The Kings College London classification simplifies the older “Todani” classification and illustrates the anatomy of the malformation.
What are the characteristics of Type 1 choledochal malformations?
• Type 1 is the most common, occurring in 80% of cases.
• Type 1C involves cystic dilatation of the common bile duct.
• Type 1F involves fusiform dilatation of the common bile duct.
• In both cases, the dilatation occurs below the confluence of the common hepatic duct and cystic duct and above the confluence of the common bile duct and pancreatic duct.
What characterizes Type 2 choledochal malformations?
Type 2 involves an out-pouching from the side of the common bile duct, located above the confluence with the pancreatic duct.
What is characteristic of Type 3 choledochal malformations?
Type 3 involves dilatation of the very distal portion of the duct, located distal to the confluence of the pancreatic and common bile duct, often bulging into the Ampulla of Vater.
What is the main feature of Type 4 choledochal malformations?
Type 4 (10-20% of cases) includes dilatation similar to Type 1C, but with numerous intra-hepatic saccular dilatations as well.
What is Type 5 choledochal malformations?
Type 5 consists of isolated lesions that are only intra-hepatic.
What is one of the most common presenting features of choledochal malformations in infants and children?
Obstructive jaundice is one of the most common presenting features of choledochal malformations.
How are choledochal malformations increasingly recognized?
Choledochal malformations are increasingly recognized during antenatal ultrasound examinations of the fetus.
How might choledochal malformations be discovered in later childhood?
In later childhood, they may be an incidental finding of an abdominal mass in the right upper quadrant (RUQ), noticed by a parent or found during an ultrasonographic examination for another reason.
What symptoms might a child with choledochal malformations present with?
A child may occasionally present with a febrile illness, abdominal pain, or frank sepsis due to bacterial infection complicating bile stasis.
How is choledochal malformations diagnosed in the postnatal period?
In the postnatal period, ultrasound is usually sufficient to confirm the diagnosis, showing a dilated extrahepatic bile duct in the context of obstructive jaundice.
What are some special investigations for choledochal malformations?
• Stool sampling to confirm pale stools.
• Blood tests to show conjugated hyperbilirubinaemia (CB >50% of total bilirubin), elevated AST/ALT, alkaline phosphatase, and gamma-glutamyl transferase (GGT). These are features of biliary obstruction, not diagnostic.
What is the first-line imaging investigation for choledochal malformations?
Ultrasound is the first-line investigation, showing cystic or fusiform dilation of the extra-hepatic and/or intra-hepatic biliary tree with dilated intra-hepatic bile ducts, possibly with stones or biliary sludge.
When is Magnetic Resonance Cholangiogram (MRCP) used in choledochal malformations?
MRCP is used when further anatomic detail is required, though it requires a high-resolution machine and may need sedation or general anaesthesia.
Why is CT abdomen typically avoided in pediatric patients with choledochal malformations?
CT abdomen is usually avoided in pediatrics due to the high radiation dose associated with the procedure.
What is the definitive treatment for choledochal malformations (CM)?
The definitive treatment for CM is surgery, specifically a hepatico-jejunostomy with a Roux-en-Y loop, to remove the diseased portion of the bile duct and reroute bile from the liver.
Why is it important to remove the diseased portion of the bile duct in CM treatment?
It is essential to remove the diseased portion to prevent malignant transformation of the affected biliary epithelium and to avoid recurrent obstruction from gallstones, bile sludge, and debris.
What is an alternative to hepatico-jejunostomy in CM surgery, and what are its risks?
An alternative is hepatico-duodenostomy, but it carries the risk of bile reflux and possibly later secondary cancer.
What is done if a patient with CM presents with overwhelming sepsis and surgery cannot be immediately performed?
If surgery cannot be performed immediately, percutaneous drainage of a large CM can be done to control the source of sepsis, in conjunction with systemic antibiotic therapy.
What are some early post-surgical complications of choledochal malformation surgery?
• Bile leak
• Anastomotic stricture/ obstruction
• Roux-loop obstruction e.g. twist
• Cholangitis
What are some late post-surgical complications of choledochal malformation surgery?
• Gallstones at anastomotic stenosis/ in dilated intra-hepatic ducts
• Cholangitis
• Bowel obstruction
What are the long-term outcomes for patients who undergo surgery for choledochal malformations?
Long-term outcomes are generally good if short-term and long-term complications are avoided, but patients require lifelong follow-up due to risks of liver fibrosis, cirrhosis, gallstones, bile stasis, and carcinoma if the malformation is not fully resected.
What long-term complications should be monitored for in choledochal malformation patients?
Long-term complications include liver fibrosis and cirrhosis (especially with late diagnosis or recurrent cholangitis), gallstones (due to bile stasis or obstruction), and carcinoma (if the malformation is not fully resected).
