Mirizzi syndrome is a rare complication of chronic gallstone disease. A large gallstone or cluster of stones becomes impacted in the gallbladder or cystic duct and swells enough to compress another duct from the outside, obstructing the flow of bile. Mirizzi syndrome can cause jaundice, inflammation and infection.
Mirizzi syndrome is a rare complication of gallstone disease. Gallstones are concentrated crystals of bile materials that develop in your gallbladder. Some people have gallstones and don’t know it because they often cause no symptoms. But one complication they can cause is obstruction of the bile ducts — the passageways that lead from your gallbladder throughout your liver. Mirizzi syndrome causes this in a particularly unusual way.
The gallbladder receives and stores bile from your liver and releases it into the small intestine through branching passageways called ducts. Sometimes gallstones wander into the ducts, and sometimes they are big enough to obstruct the flow of bile. With Mirizzi syndrome, a duct becomes obstructed from the outside when a gallstone within your gallbladder or one of the other ducts becomes so enlarged that it compresses the duct next to it.
Mirizzi syndrome is rare. Because it is so rare, and because it can resemble many other more common conditions, it often isn’t considered as a diagnosis until someone is already having surgery for gallstones. Up to 2.5% of people having their gallbladder removed are found to have Mirizzi syndrome during surgery.
Gallstones occur when there is an abundance of one of the ingredients in bile — usually cholesterol or bilirubin — and bile isn't emptied often enough or thoroughly enough from the gallbladder. As the bile sits longer in the gallbladder, bile substances concentrate and eventually clump together into solidified crystals. As new bile continues to wash over the crystals, they gradually grow into gallstones.
While gallstones are still small, they may travel. Migrating gallstones may enter either the cystic duct or the central bile duct and eventually grow big enough to get stuck there, causing inflammation and swelling in the area.
The gallbladder is shaped like a fig or a pear: it has a bulbous body that tapers at the top, then continues into a narrow tube called the cystic duct. It’s more the size of a fig, but for the top, think of a pear, how it puffs out just a little around the stem. The stem of the gallbladder is called the neck, and the puff around it is called the infundibulum, or Hartman’s pouch.
The pouch, the neck, and the cystic duct are all narrower places where a gallstone could get stuck. They also lie close beside each other — closer in some people than in others. The cystic duct branches into the common bile duct below and the common hepatic duct above. These two branches can also lie close alongside the cystic duct.
An impacted gallstone or cluster of stones in the pouch, the neck, or the cystic duct can become swollen enough to compress the common bile duct or the common hepatic duct. That’s Mirizzi’s syndrome.
Mirizzi syndrome begins with an impacted gallstone in the gallbladder or cystic duct, which can cause inflammation and infection of the gallbladder. The additional obstruction of any of the biliary ducts has several effects.
One of the more complicated effects of Mirizzi syndrome occurs when chronic inflammation between the wall that has the stone stuck in it and the wall that is being compressed begins to erode both walls. It’s something like an ulcer in the biliary system: inflammation weakens the walls, and bile erodes them until the cells in the wall actually die (necrosis) and fall away. This leads to an abnormal opening between the two branches, called a fistula.
Mirizzi syndrome is associated with an increased risk of gallbladder cancer. It is not necessarily a contributing cause. Scientists speculate that the same conditions that lead to Mirizzi syndrome also lead to cancer — that is, chronic inflammation and sludgy bile that sits too long in the gallbladder. Both conditions also share similar symptoms. In blood tests, Mirizzi syndrome is associated with high markers of the cancer antigen (CA) 19-9, but strangely, this does not always indicate cancer in Mirizzi syndrome patients. Between 5% and 28% of people with Mirizzi syndrome turn out to have gallbladder cancer. Like Mirizzi syndrome, the cancer is often not found until after surgery.
Mirizzi syndrome is treatable, but the risks increase the longer it’s left untreated. Fatality associated with Mirizzi syndrome is between 5% and 30%. It can come from systemic infection (sepsis), from liver failure or from associated gallbladder cancer.
Symptoms of Mirizzi syndrome fall into three categories:
Not everyone will have all of these. If you do, it indicates a problem with the biliary system, but not necessarily Mirizzi syndrome.
The symptoms listed above are not specific to Mirizzi syndrome, but they are enough to suspect gallstones with complications. There are a variety of tests used to diagnose gallstone disease. Your healthcare provider may begin with a blood test to look at liver enzyme levels if you have jaundice or for elevated white blood cells if you have signs of infection. To look for signs of inflammation or gallstones in the organs, they may begin with an abdominal ultrasound.
If your gallbladder is swollen with built-up bile, your healthcare provider may suspect gallbladder cancer. This is based on an old rule called Courvoisier's law. According to the law, if your gallbladder is palpable (Courvoisier’s gallbladder), it means you probably don’t have gallstones, because the resulting inflammation would have caused the gallbladder to harden over time, preventing it from swelling. However, Mirizzi syndrome is the rare exception to this law.
If your healthcare provider suspects an obstruction in one of the ducts — whether a gallstone or a tumor — they may then proceed to a more specific imaging test, such as a CT scan, an MRI or an ERCP. The ERCP test is the gold standard for diagnosing Mirizzi syndrome, but healthcare providers won’t always use it if they don’t suspect Mirizzi syndrome. In general, Mirizzi syndrome is more often successfully diagnosed when healthcare providers use two or more kinds of imaging tests. Between 18% and 62% of cases are diagnosed before surgery.
Surgery is the mainstay in treatment for most gallbladder complications. When stones block or compress bile ducts, the situation becomes more complex. In these instances, surgeons and gastroenterologists collaborate closely as each may have a role to play in the treatment. Because Mirizzi syndrome has so many variations, there is no standard procedure to manage it — the surgery will be specific to your condition. In general, your gallbladder will likely be removed and the blocked duct will be relieved.
Gallbladder removal is commonly done laparoscopically, through small incisions aided by a tiny scope. However, your surgeon may have to convert this less-invasive method to open surgery if they find Mirizzi syndrome, which may be more surgically complex. In addition to removing the gallbladder, sometimes impacted bile ducts may need to be removed and the ends reattached. Stents or tubes may be placed to open up narrowed passageways.
If your gastroenterologist discovered your Mirizzi syndrome during an ERCP scan, they might be able to partially treat it then, using the endoscope to remove a stone and guide the placement of stents to open up a narrowed duct. This can help by relieving the obstruction of bile in the ducts, even if gallbladder removal is still necessary afterward. For those who may not be suitable candidates for surgery, this might be the only treatment option.
Surgery for Mirizzi syndrome is challenging, especially if the condition isn’t fully understood before surgery. The anatomy involved can be hard to see well in advance, and often the condition distorts the anatomy. Severe inflammation can cause the organs and ducts to swell, thicken and harden. This makes it easy to accidentally injure the bile ducts during surgery. An accidental injury could lead to excessive bleeding or hemorrhage, as well as bile leakage, which could lead to infection. It could also cause scarring of the bile ducts, leading to further complications down the road.
Despite the complications involved, usually surgery successfully treats Mirizzi syndrome. The key is to treat it early enough to avoid the long-term effects of the condition. The more your organs and ducts have been damaged, the more complicated the surgery will be, and the longer your recovery time. However, most people recover well and live well without their gallbladder.
A note from Cleveland Clinic
Mirizzi syndrome is rare, but gallstones are common. You may have them and not even know it. You can reduce your risk of cholesterol stones, which are the most common type, by reducing cholesterol in your diet. The rest is unpredictable. The best thing you can do is to stay alert to symptoms of jaundice, inflammation or infection and take these symptoms seriously. Bile needs to flow, and an obstructed bile duct will feel increasingly bad. Don’t prolong it. The sooner you seek medical care, the sooner you’ll be on your way to recovery.
Last reviewed by a Cleveland Clinic medical professional on 11/30/2021.
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