thumb|Impacted gallstone in the cystic duct is obstructing the common hepatic duct
Mirizzi's syndrome is a rare complication in which a gallstone becomes impacted in the cystic duct or neck of the gallbladder causing compression of the common hepatic duct, resulting in obstruction and jaundice. The obstructive jaundice can be caused by direct extrinsic compression by the stone or from fibrosis caused by chronic cholecystitis (inflammation). A cholecystocholedochal fistula can occur.
Pathophysiology
Multiple and large gallstones can become impacted in the Hartmann's pouch of the gallbladder, leading to chronic inflammation—which leads to compression of the common bile duct (CBD), necrosis, fibrosis, and ultimately fistula formation into the adjacent common hepatic duct (CHD) or common bile duct (CBD). As a result, the CHD/CBD becomes obstructed by either scar or stone, resulting in obstructive jaundice. It can be divided into four types.
Type I – No fistula present
- Type IA – Presence of the cystic duct
- Type IB – Obliteration of the cystic duct
Types II–IV – Fistula present
- Type II – Defect smaller than 33% of the CHD diameter
- Type III – Defect 33–66% of the CHD diameter
- Type IV – Defect larger than 66% of the CHD diameter
Diagnosis
Imaging by ultrasonography, MRCP, or CT scan usually make the diagnosis. MRCP can be used to define the lesion anatomically prior to surgery.
Occasionally Mirizzi's syndrome is diagnosed or confirmed on ERCP when requested to alleviate obstructive jaundice or cholangitis by means of an endoscopically placed stent, or when USS has been wrongly reported as choledocolithiasis.
Treatment
Simple cholecystectomy is suitable for type I patients. For types II–IV, subtotal cholecystectomy can be performed to avoid damage to the main bile ducts. Cholecystectomy and bilioenteric anastomosis may be required. Roux-en-Y hepaticojejunostomy has shown good outcome in some studies.
Epidemiology
Mirizzi's syndrome occurs in approximately 0.1% of patients with gallstones. It is found in 0.7 to 2.5 percent of cholecystectomies. In 1931, he performed the first intraoperative cholangiogram. Mirizzi suggested the name of the phenomenon would be "hepatic duct syndrome."