Mirizzi's syndrome is caused by an impacted gallstone in the cystic
duct or the neck of the gallbladder that compresses the adjacent bile
duct and results in complete or partial obstruction of the common
hepatic bile duct. It is often not recognized pre-operatively, which
can lead to significant morbidity and biliary injury. A review of the
ailment has been posted
Wednesday, May 7, 2008
Mirizzis syndrome
Introduction
* Mirizzis syndrome is caused by an impacted gallstone in the cystic duct
or the neck of the gallbladder that compresses the adjacent bile duct and
results in complete or partial obstruction of the common hepatic bile duct.
* It is often not recognized preoperatively, which can lead to significant
morbidity and biliary injury, particularly with laparoscopic surgery.
In 1905, Kehr first reported on external compression of the bile duct following
stone impaction in the cystic duct. However, the syndrome was named after the
Argentinian surgeon Pablo Mirizzi, who described in 1948 a hepatic duct
obstruction due to cholelithiasis and cholecystitis as syndrome del conducto
hepatico
Incidence
* In the largest series, including 17,000 patients undergoing open surgery
for gallstone disease, 219 patients (1.3%) had Mirizzis syndrome and/or
cholecystobiliary fistula.
* This figure may rise up to 2.7% in high-risk populations such as native
American Indians.
* The recently published, largest series of 13,023 cases on laparoscopic
cholecystectomy found Mirizzis syndrome and/or cholecystobiliary fistula in
0.3% of patients.
* Approximately 50 to 77% of all patients reported are women, probably
reflecting the increased incidence of the gallstone disease in the female
population.
A correlation was also noted between the stage of the disease and the mean age
of patients.
* In patients with type A disease the mean age was 44 years while the mean
age was 62 years in patients with type C compression.
Classification
McSherry et al. initially classified this syndrome into two types.
* Type I involves the external compression of the common hepatic duct due
to a stone impacted in the neck of the gallbladder or the cystic duct.
* Type II refers to cholecystocholedochal fistula and stone migration into
the common hepatic duct.
A further modification of this classification was suggested by Csendes et al.,
in which
* type II is an obstruction that involves less than one-third of the bile
duct,
* type III is an obstruction involving up to two-thirds of the duct, and
* type IV is complete obstruction of the bile duct.
The third classification expanded the definition of the Mirizzi syndrome :
* Type I referred to a stone impacted in the cystic duct or gallbladder
neck.
* Type II was characterized by a fistula of the common duct.
* Type III was defined by hepatic duct stenosis due to a stone at the
confluence of the hepatic and cystic ducts.
* Type IV was characterized by hepatic duct stenosis as a complication of
cholecystitis in the absence of calculi impacted in the cystic duct or
gallbladder neck.
Pathophysiology
* Mirizzis syndrome may be caused by either a single large stone or
multiple small stones impacted in the Hartmanns pouch of the gallbladder or in
the cystic duct.
* Anatomically, a long cystic duct parallel to the bile duct predisposes to
the development of this syndrome.
* Recurrent cystic duct obstruction may lead to recurrent attacks of
cholecystitis and may cause gallbladder dilatation, thickening, and
inflammation.
Impaction of a large gallstone (or multiple small gallstones) in the Hartmann
pouch or cystic duct results in the Mirizzi syndrome in 2 ways:
* (1) chronic and/or acute inflammatory changes lead to contraction of the
gallbladder,
o which then fuses with and causes secondary stenosis of the CHD,
o there may present episodes of cholangitis which further increases
inflammatory process,
* (2) large impacted stones lead to cholecystocholedochal fistula formation
secondary to direct pressure necrosis of the adjacent duct walls.
* Increasingly, these phenomena are seen not as distinct and separate steps
but as part of a continuum.
* This hypothesis is supported by the observation that in most cases the
cholecystocholedochal fistula is occupied by a large impacted gallstone in the
fistula tract.
Clinical signs
Mirizzis syndrome is typically seen in the setting of longstanding biliary
symptoms.
* Obstructive jaundice is the key feature of Mirizzis syndrome and is
frequently accompanied by pain and fever.
* This presentation often suggests acute cholangitis.
* Rarely, patients may be anicteric at presentation.
* Patients can also present with cholecystitis or pancreatitis.
Laboratory data are not specific, with hyperbilirubinemia as the most
encountered laboratory abnormality. Elevated levels of alkaline phosphatase and
transaminases are also common. Leukocytosis is a frequent presence in
concomitant acute cholecystitis, pancreatitis, or cholangitis.
Diagnosis
* In clinical practice, the diagnosis is rarely made preoperatively.
The diagnostic approach usually begins with ultrasonography followed by
cholangiography via direct cholangiography, endoscopic retrograde
cholangiopancreatography, or magnetic resonance cholangiography.
Endoscopic retrograde cholangiopancreatography (ERCP) is the procedure of
choice to establish the diagnosis and to classify the lesion.
* Mirizzi type A presents as an extrinsic compression of the common hepatic
duct by a distended gallbladder with dilatation of the intrahepatic biliary
tree.
* ERCP is also essential in determining the presence of a fistula
preoperatively.
* Percutaneous transhepatic cholangiography (PTC) can provide similar
information.
* However, ERCP can identify a low-lying cystic duct that may be missed by
PTC.
* In addition, PTC may not visualize the distal common bile duct because of
the obstruction in the hepatic duct.
* Finally, as discussed below, ERCP offers the opportunity to exercise a
variety of therapeutic options including stone retrieval and stenting.
Ultrasonography generally reveals gallstones and a contracted gallbladder.
Features suggestive of Mirizzi syndrome include :
* Dilatation of the biliary system above the level of the gallbladder neck.
* The presence of a stone impacted in the gallbladder neck.
* An abrupt change to a normal width of the common duct below the level of
the stone.
The literature regarding the use of a CT scan for the diagnosis of Mirizzis
syndrome is controversial.
* Some authors feel that CT does not provide any additional information
beyond what can be obtained with ultrasonography; also, the presence of
periductal inflammation can be misinterpreted as carcinoma of the gallbladder.
* Overall, CT may be helpful in excluding malignancies in the pancreas, the
porta hepatis area, or the liver.
The differential diagnosis includes other causes of obstructive jaundice such
as malignancies (e.g., cholangiocarcinoma, carcinoma of the gallbladder, or
pancreatic cancer) and sclerosing cholangitis.
Treatment
Surgery remains the treatment of choice for Mirizzis syndrome.
* The choice of surgery is determined by whether a fistula into the bile
duct is present.
* The common surgical approach is usually an incision in the gallbladder
fundus and removal of the impacted stone.
* A gush of bile indicates a fistula, because the cystic duct is usually
occluded.
A standardized surgical approach has been recommended based on the
classification of the variants of Mirizzi syndrome:
* Type I Cholecystectomy plus common bile duct exploration with T-tube
placement. Exploration should be performed only if the CBD is easily exposed.
* Type II Suture of the fistula with absorbable material or
choledochoplasty with the remnant gallbladder.
* Type III Choledochoplasty; suture of the fistula is not indicated.
* Type IV Bilioenteric anastomosis is preferred since the entire wall of
the common bile duct has been destroyed.
In any case, excellent drainage should be achieved.
A serious complication of the surgical approach is the ligation of the hepatic
duct because a normal caliber hepatic duct may be mistaken for a dilated cystic
duct that runs parallel to it.
Laparoscopic surgery
* The Mirizzi syndrome presents a difficult challenge for laparoscopic
surgery because the dense adhesions and edematous inflammatory tissue cause
distortion of the normal anatomy and increase the risk for biliary injury.
* Thus, the use of laparoscopic surgery as the primary treatment of Mirizzi
syndrome is controversial, although it appears to be feasible, especially for
type I anatomy.
* It has been suggested that a prudent policy is to perform a dissection
trial and convert to an open procedure if local conditions are not clear for an
experienced laparoscopic surgeon.
* The largest series on Mirizzis syndrome identified during laparoscopic
cholecystectomy reported a conversion rate of 71% for type A and 100% for type
B/C.
Endoscopic therapy
* The endoscopic treatment is not only for the evaluation, but also for the
treatment of Mirizzis syndrome.
* Whether it is used as primary therapy or in addition to surgical
treatment, ERCP is an attractive alternative and may be the only option for
high-risk patients.
* In general, endoscopic management includes both biliary drainage and
stone removal.
* Endoscopic sphincterotomy is generally recommended for stone extraction.
* Standard stone removal techniques are usually used and include baskets,
balloons, and mechanical and electrohydraulic lithotripsy.
* The latter may be a valuable modality if standard techniques have failed.
* However, multiple treatment sessions may be required and leakage of
contrast material from the cystic duct into the peritoneal cavity has been
described after the fragmentation of large stones.
Further advances in the design of retrograde cholangioscopes may make this
option more attractive in the future.
Association with cancer
* The Mirizzi syndrome has been associated with a high frequency of
gallbladder cancer.
* In one series of 1759 cholecystectomies, 18 cases of Mirizzi syndrome
were identified; five (28 percent) had coincidental gallbladder carcinoma
(versus only 2 percent in the patients without Mirizzi syndrome).
* An intraoperative frozen section of the gallbladder wall should be
sampled.in particular in the presence of markedly elevated CA 19-9 levelsto
exclude carcinoma.
The patients with gallbladder carcinoma had a longer history of preexistent
gallbladder disease (10.4 versus 6.8 years in those without carcinoma).
* The serum concentration of the tumor-associated antigen CA 19-9 was
elevated in 12 of the 18 patients with Mirizzi syndrome but was significantly
higher in those with malignancy (peaking at 1000 U/mL).
Although gallbladder carcinoma may be common in patients with Mirizzi syndrome,
the latter disorder is unusual among patients with gallbladder carcinoma.
Mortality and morbidity
* In the largest series, Csendes reported no operative mortality (within 30
days of operation) in patients with type 1 disease, 2 to 12% with type 2, and
11% with type 3 disease.
Late mortality due to biliary disease was below 5% with any stages of the
disease.
* The largest series of Mirizzis syndrome, which was found during intended
laparosopic cholecystectomy, had no mortality for all types.
Postoperative morbidity includes mainly the development of
* external biliary fistula,
* bile peritonitis, and
* subphrenic abscess.
* The incidence of benign strictures of the bile duct occurs in 4 to 11% of
patients.
Posted by jitendraagrawal2000 at 11:48 AM
Dr. Jitendra Agrawal, Kanpur, India.
