Mirizzi Syndrome
Definition
- Mirizzi syndrome is an uncommon condition characterized by extrinsic obstruction of the common hepatic duct due to an impacted gallstone in the gallbladder infundibulum (Hartmann pouch) or the cystic duct.
- Occurs in 0.3% to 3% of patients undergoing cholecystectomy.
Pathogenesis
- An impacted stone causes inflammation and compression of the bile duct.
- Prolonged inflammation may lead to erosion and formation of a cholecystocholedochal fistula (between the gallbladder and common hepatic duct).
Classification
- Type I: External compression of the common hepatic duct by an impacted stone.
- Type II: Erosion of the gallstone into the common hepatic duct, creating a fistula.
- Type IIa: Involvement of less than one-third of the bile duct circumference.
- Type IIb: Involvement of up to two-thirds.
- Type IIc: Complete erosion of the bile duct wall.
- Type V: Presence of a cholecystoenteric fistula (with or without gallstone ileus) alongside any of the other types.
Clinical Features
- Symptoms of acute cholecystitis (right upper quadrant pain, fever).
- Jaundice due to bile duct obstruction.
- Elevated bilirubin and alkaline phosphatase levels.
- Possible cholangitis if infection develops.
Imaging and Diagnosis
- Ultrasound:
- Dilated biliary tree proximal to the gallbladder neck.
- Impacted gallstone at the gallbladder infundibulum or cystic duct.
- Abrupt change in common duct caliber below the stone.
- Computed Tomography (CT):
- Eccentrically located impacted gallstone.
- Dilated proximal biliary system with normal downstream ducts.
- Irregular cavity with surrounding edema near the gallbladder neck.
- Magnetic Resonance Cholangiopancreatography (MRCP) or Direct Cholangiography (ERCP/PTC):
- Detailed visualization of the obstruction and any fistula.
- Preoperative diagnosis is crucial for appropriate surgical planning.
Complications
- Formation of cholecystobiliary and cholecystoenteric fistulae.
- Increased risk of gallbladder carcinoma.
- Development of biliary strictures.
Management
- Open cholecystectomy is the gold standard treatment.
- Type I:
- Standard cholecystectomy may suffice.
- If inflammation is severe, a partial cholecystectomy may be necessary.
- Type II:
- May require biliary reconstruction due to bile duct erosion.
- Options include:
- Primary repair of the bile duct.
- T-tube placement for bile drainage.
- Roux-en-Y hepaticojejunostomy for biliary-enteric drainage.
- Type I:
- Laparoscopic approach is generally not recommended due to high conversion and complication rates.
- Endoscopic interventions:
- ERCP can aid in diagnosis and may provide biliary decompression.
- Placement of biliary stents to assist during surgery.
Surgical Considerations
- Inflammation and fibrosis can distort the anatomy of the triangle of Calot, increasing the risk of bile duct injury.
- Preoperative imaging is essential to identify anatomical variations and plan surgery.
- In severe cases, subtotal cholecystectomy may be the safest option.
Related Conditions
Cholecystoenteric Fistula
- Definition: A fistula between the gallbladder and an adjacent hollow organ (usually the duodenum or transverse colon).
- Etiology: Result of gallbladder perforation due to acute cholecystitis.
- Clinical Features:
- Pneumobilia (air in the biliary tree).
- Cholangitis from bacterial contamination.
- Gallstone ileus causing small bowel obstruction.
- Chronic diarrhea in cholecystocolonic fistula.
- Management:
- Cholecystectomy with fistula takedown and closure.
- Enterotomy to remove obstructing stones in gallstone ileus.
- Surgical approach depends on patient stability and inflammation severity.
Cholecystocholedochal Fistula
- Definition: A fistula between the gallbladder and the common bile duct.
- Pathogenesis: Impacted gallstones erode into the bile duct due to prolonged inflammation.
- Management:
- Near-total cholecystectomy while preserving bile duct integrity.
- Biliary reconstruction if necessary.
- Endoscopic and minimally invasive approaches are emerging but require expertise.
Alternative Diagnoses in Hilar Strictures and Jaundice
- While cholangiocarcinoma is common, consider:
- Gallbladder carcinoma:
- Thickened, irregular gallbladder wall.
- Infiltration into liver segments IV and V.
- Obstruction of the mid–bile duct with cystic duct occlusion.
- Benign focal strictures:
- Autoimmune cholangitis.
- Primary sclerosing cholangitis (PSC).
- Lymphoplasmacytic sclerosing pancreatitis/cholangitis.
- Granulomatous diseases.
- Gallbladder carcinoma:
Key Points
- Early recognition and preoperative diagnosis are essential to reduce surgical complications.
- Open surgical approach is preferred due to distorted anatomy and high risk of bile duct injury.
- Minimally invasive techniques are being explored but should be approached cautiously.
- Awareness of related conditions and alternative diagnoses is important for comprehensive management.
Note: Bolded terms highlight key concepts and terminology for emphasis and easier revision.