Emergency General Surgery

The Devil Behind the Curtains

Leave no stone unturned.


Hi guys… Happy to see you here again…

Today we are going to talk about a quite uncommon, but yet important, topic…

We know it has been a while since we reported a clinical case, and we are sorry for that… Therefore, today we are going to start with one…

You are obviously on call, and Mark, your ER colleague, calls you for an old woman presenting with abdominal pain and distension and vomiting.

At your arrival, the patient is feeling a little bit better, but she is not ok at all. The abdomen is moderately distended and painful. Lab exams are of no help: she has slightly increased WCC and CRP, no lactates, no electrolytes imbalances. Mark asked for a plain abdominal x-ray that showed small bowel distension, air-fluid levels, and a round-shaped radiolucent foreign body in the right iliac fossa.

What to do next? What’s your diagnosis?


In previous posts, we have already talked about the complications of acute cholecystitis (diagnosis & management)… Today we will explore the rare chronic complications of gallstones.

The main difference between these complications and those following acute cholecystitis is that the chronic ones are usually the first manifestation of the biliary disease.

The main chronic complications are:

  • Mirizzi syndrome;
  • Cholecystocholedochal (or cholecystobiliary) fistula;
  • Gallstone ileus;
  • Gallbladder cancer.

The first three are basically different phases of the same process, and they can be included together into the big family of the Mirizzi syndrome.

In this post, we are not going to talk about gallbladder cancer, since it is not a surgical emergency. Just to know, it may evolve from a chronic inflammatory process and be accidentally discovered during cholecystectomy… More or less the same thing that may happen for appendiceal neoplasms… Remember that patients with Mirizzi syndrome are at particularly high risk, with gallbladder cancer involving 6-28% of specimens.

Mirizzi syndrome was first described in 1948 as a syndrome of hepatic duct obstruction caused by an impacted gallstone in the neck of the gallbladder or the cystic duct compressing the main bile duct nearby. The obstruction can be partial or complete, depending on the grade of compression.

The pathophysiological pathway is quite straightforward: impacted gallstones cause a chronic inflammatory process that makes the gallbladder fuse with the main bile duct, and this may cause an external obstruction of the bile duct. With time, this chronic inflammation may cause a progressive erosion of the gallbladder and bile duct walls, resulting eventually in a cholecystocholedochal or cholecystohepatic fistula. If the same process happens between the gallbladder and a hollow viscus, this may end with a cholecystoenteric fistula, and, possibly, with gallstone ileus.

Clinical Presentation and Diagnosis

Only a few cases of Mirizzi syndrome present clinically, where most of them are found during cholecystectomy. In fact, the incidence of Mirizzi syndrome during biliary surgery is about 0.7-1.4%, and that of cholecystocholedochal fistula is 1.1%.

In the few cases with a clinical manifestation, this usually includes fever, abdominal pain, and jaundice… Basically, acute cholangitis…

Obviously, the laboratory findings reflect the biliary infection: leukocytosis, hyperbilirubinemia, elevated ALP, and aminotransaminase levels.

Signs of Mirizzi syndrome can be found with multiple imaging techniques: ultrasound, CT scan, and MRI. Usually, the imaging report describes a contracted gallbladder with one or more gallstones impacted in the cystic duct, causing dilation of intrahepatic bile ducts and common hepatic duct with a normal-sized common bile duct. However, these findings may be slightly different from case to case, and the biliary duct dilation may not be present at all.

In general, we suggest the use of a magnetic resonance cholangiopancreatography (MRCP) in all patients with a suspicion of Mirizzi syndrome to confirm it and to obtain a good overview of the biliary anatomy.

Endoscopic retrograde cholangiopancreatography (ERCP) is another useful method to diagnose Mirizzi syndrome. Moreover, it offers multiple possible therapeutic options. However, considering its invasive nature, it cannot be offered as a mere diagnostic technique.


As always, multiple classification systems exist for Mirizzi syndrome… They are a good way to be published and obtain citations after all…

By the way, the most famous classification was made by Csendes et al., and it described 4 types of Mirizzi syndrome:

  • Type 1 – Extrinsic compression of the common bile duct by an impacted gallstone;
  • Type 2 – Cholecystobiliary fistula involving ≤1/3 of the circumference of the bile duct;
  • Type 3 – Cholecystobiliary fistula involving up to 2/3 of the circumference of the bile duct;
  • Type 4 – Cholecystobiliary fistula comprising the whole circumference of the common bile duct and causing complete obstruction of the bile duct.

Recently, this classification was modified, and Type 5 was introduced:

  • Type 5 – Cholecystoenteric fistula with any type above
    • Type 5A – Without gallstone ileus;
    • Type 5B – With gallstone ileus.
Drawings by Beltran MA, et al.


As we said before, unfortunately, in the majority of cases Mirizzi syndrome is found directly during biliary surgery. This event may change drastically the surgical approach, leading to a high rate of conversion and/or serious complications (e.g. bile duct injury).

It seems unnecessary to say and quite obvious, but the best approach to the Mirizzi syndrome starts with a complete preoperative diagnosis and planning.

The laparoscopic approach is usually reserved only in Type 1 Mirizzi syndrome since it is associated with a high risk of serious complications. The common surgical approach includes opening the gallbladder and extraction of the impacted gallstone. If bile is noted after the stone removal, this indicates a cholecystobiliary fistula. An intraoperative cholangiography is generally carried out to confirm the absence of a fistula. If no fistula is recorded, a total/partial cholecystectomy is performed. On the contrary, if a fistula is identified, then a cholecystocholedochoduodenostomy or a Roux-en-Y hepaticojejunostomy may be done. If possible, direct repair of the fistula over a T tube may be attempted as well. In this setting, the gallbladder wall can be used as a flap to help reconstruct the bile duct.

Gallstone Ileus

Gallstone ileus is a peculiar bowel obstruction secondary to the migration of one or more large biliary stones into the hollow viscus that occludes the lumen. It is quite rare, and it accounts for 5% of all gastrointestinal obstruction.

It develops more often in the elderly (>70 years old), and in particular in women (72-90%).

The pathophysiological process behind this clinical picture is quite simple and it is the same as for the Mirizzi syndrome: chronic inflammation, adhesion formation between the gallbladder and a hollow viscus (e.g. most-frequently duodenum, transverse colon, and stomach), erosion of the two walls (gallbladder and viscus) by the pressure effect of the biliary stone, fistula formation, stone migration and, finally, stone impaction.

Obviously, not all migrated stones got impacted… In this case size matters… Usually, stones bigger than 2-2.5 cm are at higher risk of impaction, where the smaller ones pass spontaneously through the gastrointestinal tract and are expelled with stools.

Another important factor to consider in gallstone ileus is the site of impaction. Although it may be in any site of the gastrointestinal tract, there are some points at higher risk because of anatomical factors. The most frequent site of impaction is the terminal ileum, at the level of the ileocecal valve. Two unusual sites of impaction are the pylorus and the duodenal bulb, giving the so-called Bouveret’s syndrome.

Patients with a gallstone ileus usually have a positive history of biliary symptoms (about two-thirds of cases). The clinical picture is that of intestinal obstruction. In the case of Bouveret’s syndrome, patients manifest signs and symptoms of gastric outlet obstruction. In simple words, signs and symptoms of gallstone ileus are nonspecific and most commonly do not allow a precise diagnosis.

The diagnosis of gallstone ileus may be made with just a plain abdominal x-ray, recognizing the so-called Rigler’s triad:

  1. Signs of intestinal obstruction (i.e. dilated bowel loops, air-fluid levels);
  2. Pneumobilia;
  3. Ectopic gallstone (that may change position on serial x-rays).

The Rigler’s triad is found in 14-53% of cases though. So, it is not possible to rely on it to make a diagnosis. The imaging technique to use in the case of suspected gallstone ileus (or in the case of unspecified intestinal obstruction) is the abdominal contrast-enhanced CT scan, with a sensitivity of about 93%. Other imaging techniques that may be used for the diagnosis are ultrasound and MRCP. However, the first has a lower sensitivity compared to the CT scan, and the second one is usually more complicated to obtain in an emergency setting. Still, MRCP may be useful when the diagnosis is not certain after a CT scan.

Once the diagnosis is made, the treatment is surgical. In literature are reported cases of stones impacted in the colon or the stomach/duodenum treated endoscopically; however, they are isolated events.

There are three possible surgical procedures to treat these patients:

  1. Simple enterolithotomy;
  2. Enterolithotomy, cholecystectomy and fistula closure (one-stage procedure);
  3. Enterolithotomy with cholecystectomy performed later (two-stage procedure).

Many studies have focused on the great question: which one is the best?…

In the end, as always, a simple answer is not possible, and the only one given is “it depends”…

Simple enterolithotomy should be the procedure of choice since it carries lower morbidity and mortality. During laparotomy, careful examination of the whole bowel, gallbladder, and bile ducts should be made to exclude residual gallstones, bile leakage, abscess, and/or necrosis. Afterward, the bowel should be opened with a longitudinal incision on the antimesenteric border proximal to the site of impaction (possibly on a non-inflamed bowel loop), the gallstone extracted, and the incision closed transversely to avoid narrowing the intestinal lumen.    

The one-stage procedure should be reserved in the case of patients with acute cholecystitis, necrotic gallbladder, or residual gallstones (recurrence rate of 8% within 30 days with enterolithotomy alone). On the other hand, the two-stage procedure finds its indication in patients with persistent biliary symptoms, and the second operation should be performed 4-6 weeks after the enterolithotomy.

In general, if you are not an expert in the management of the difficult bile duct and gallbladder, we suggest leaving it there for the next operation (if needed), maybe transferring the patient to a hospital with a hepatobiliary department.

Remember that patients with gallstone ileus are old and, generally, with concomitant medical conditions. Therefore, many of them only need the resolution of the bowel occlusion, especially if the gallbladder has a wide fistula draining the bile content. Moreover, they should be followed and treated carefully during the postoperative period. Post-operative complications, mostly related to their previous medical conditions, are quite common. Finding yourself in a complex operation, lasting hours, on a highly fragile patient is not a good idea, and neither is a good service to the patient. Think it wisely before adventuring in an exploration of the gallbladder in an “asymptomatic” patient from the biliary point of view (the patient has “only” a bowel occlusion and nothing more)!

We know that the Mirizzi syndrome, with all its facets, is quite rare… However, it is mandatory to have basic knowledge about it to keep a high index of suspicion. The identification of a Mirizzi syndrome preoperatively allows to carefully plan the surgical procedure, thus reducing the risk of bile duct injury.

See you next time.


  1. Abou-Saif A, et al. Complications of gallstone disease: Mirizzi syndrome, cholecystocholedochal fistula, and gallstone ileus. Am J Gastroenterol 2002;97:249-54.
  2. Beltran, MA. Mirizzi syndrome: history, current knowledge and proposal of a simplified classification. World J Gastroenterol 2012;18:4639-50.
  3. Mirizzi PL. Sndrome del conducto heptico. J Int Chir 1948;8:731-777.
  4. Csendes A, et al. Mirizzi syndrome and cholecystobiliary fistula: a unifying classification. Br J Surg 1989;76:1139-43.
  5. Csendes A, et al. Mirizzi syndrome and cholecystobiliary fistula: a unifying classification. Br J Surg 1989;76:1139-43.
  6. Nuno-Guzman CM, et al. Gallstone ileus, clinical presentation, diagnostic and treatment approach. World J Gastroenterol Surg 2016;27:65-76.

How to Cite This Post

Bellio G, Marrano E. The Devil Behind the Curtains. Surgical Pizza. Published on February 26, 2022. Accessed on November 27, 2022. Available at [https://surgicalpizza.org/emergency-surgery/the-devil-behind-the-curtains/].

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