What are Bile Duct Stones?

Bile duct stones (also known as choledocholithiasis) are solid crystals of cholesterol found in the bile ducts, which are tubes that carry bile from the liver to the small intestine. These stones could also be made of bilirubin (the main pigment in bile) and calcium. They can range in size, from small grains to golf-ball-sized stones.

When these stones become stuck in the bile duct, medical intervention is necessary to prevent inflammation, infection or organ damage.

What is the Difference between Bile Duct Stones and Gallbladder Stones?

Bile duct stones and gallbladder stones are the same. However, as their names suggest, they differ in location. Bile duct stones are found in the bile duct and could have been transported to the bile duct from the gallbladder or formed in the bile duct itself. 

Why are Bile Duct Stones a cause for concern?

Persistent blockage caused by bile duct stones can cause serious infection of the bile duct (acute cholangitis) or inflammation of the gallbladder (acute cholecystitis). 

When inflamed, bacteria can spread to the bloodstream and cause serious infections in other parts of the body (sepsis) and fever. Further complications could arise, such as the inflammation of the pancreas (pancreatitis) and liver abscess (accumulation of pus in the liver).

An untreated blockage can lead to life-threatening conditions such as cholangitis or pancreatitis. 

What Causes Bile Duct Stones?

Bile duct stones are often a consequence of gallbladder stones moving into the bile duct. 

The role of bile

Bile serves as an emulsifier, breaking down large fat globules into smaller particles. It is produced by the liver and stored in the gallbladder. When we consume food, the gallbladder releases bile to aid in digestion and absorption. It is made up of:

• Cholesterol
• Bile salts
• Bilirubin
• Water
• Body salts
• Metals

When the liver secretes more cholesterol than the bile can dissolve, the excess cholesterol forms solid particles and accumulates in bile in the gallbladder. On other occasions, stones may develop in the bile duct and become lodged there.

Your bile may contain too much cholesterol, too much bilirubin or the gallbladder does not empty correctly, contributing to the formation of gallstones.  

Factors that increase the risk of developing bile duct stones include:

• High-cholesterol  
• Obesity
• Rapid weight loss
• Prolonged fasting/parenteral nutrition
• Spinal cord injury
• Family history
• Liver cirrhosis (scarring of the liver)/jaundice
• Crohn’s disease/ileal resection
• Hereditary blood cell disorders (e.g. Sickle Cell Anaemia)
• Being above the age of 40
• Female sex
• Pregnancy
• Diabetes mellitus
• Medications (e.g. fibrates, ceftriaxone, somatostatin analogues, hormone replacement therapy, oral contraceptive pills)

What foods cause bile duct stones?

High-fat and processed foods may slow the gallbladder’s ability to help the body digest fat. As mentioned earlier, the liver secretes more cholesterol than the bile can dissolve. Hence, the excess cholesterol forms solid particles and accumulates in bile in the gallbladder. Conversely, a high-fibre and low-fat diet may help prevent bile duct stones. 

What are the Symptoms of Bile Duct Stones?

• Pain in the upper abdomen, especially after eating
• Light-coloured stools
• Jaundice (yellowing of the skin or eyes)
• Fever
• Nausea and vomiting 
• Dark-coloured urine

However, it is also possible for people with bile duct stones to have no symptoms.

How are Bile Duct Stones diagnosed?

To visualise the gallbladder and bile duct and identify the bile duct stones, the doctor can order imaging tests such as an ultrasound, computerised tomography (CT) scan, and magnetic resonance imaging (MRI).

Other diagnostic tests are:

• Magnetic resonance cholangiopancreatography (MRCP) — A type of MRI that produces detailed images of the liver, gallbladder, bile ducts, pancreas and pancreatic duct. 

• Endoscopic ultrasound — An endoscopic procedure with an ultrasound component that emits sound waves to produce detailed images of the linings of the gastrointestinal tract. 

How are Bile Duct Stones Treated?

Endoscopic or operative procedures can be conducted to remove bile duct stones. 

A complex endoscopic procedure known as Endoscopic Retrograde Cholangiopancreatography (ERCP) can be performed to remove these stones. This involves the insertion of an endoscope through the mouth and into the digestive tract. The stones are then removed using baskets or balloons. 

During ERCP, an endoscope is placed through the mouth to the start of the small intestine, and stones are removed using a basket or an extraction balloon.  

• Mechanical lithotripsy — larger bile duct stones are broken up into smaller particles using a wire basket and removed through the endoscope.

• Intraductal electrohydraulic lithotripsy — a tiny probe inserted through the endoscope is used to produce shockwaves that break the bile duct stones into smaller pieces which are removed through the endoscope.

Surgery to remove the gallbladder is also recommended to prevent future occurrence of bile duct stones and other gallstone related problems. To treat infection in the bile duct, antibiotics are prescribed. 

Generally, patients can go home the day after the procedure following overnight observation. 

Dr Benjamin Yip reminds us: “Once you have your bile duct stones cleared by your Gastroenterologist, be sure to ask him/her to refer you to a Surgeon to have your gallbladder removed as they often contain stones as well. If not, your bile duct stones may recur, causing you to have further problems down the road.”

Summary 

Bile duct stones are often the result of gallbladder stones migrating into the bile duct and require medical intervention to prevent inflammation and life-threatening infections. If you experience any of the aforementioned symptoms, please consult a Gastroenterologist for proper diagnosis and treatment. 

References

1. “Bile duct obstruction: Causes, symptoms, and treatment.” Medical News Today, 11 June 2018, https://www.medicalnewstoday.com/articles/322095. Accessed 19 May 2022.
2. “Bile Duct Obstruction: Symptoms, Treatment, and Causes.” Healthline, https://www.healthline.com/health/bile-duct-obstruction. Accessed 19 May 2022.
3. “Bile Duct Stones.” Michigan Medicine, https://www.uofmhealth.org/conditions-treatments/digestive-and-liver-health/bile-duct-stones. Accessed 19 May 2022.
4. Gonzalez, Andrew. “Bile duct stones: Symptoms, causes, and treatment.” Medical News Today, 29 March 2021, https://www.medicalnewstoday.com/articles/bile-duct-stones. Accessed 19 May 2022.
5. “MRCP (MR Cholangiopancreatography).” RadiologyInfo.org, https://www.radiologyinfo.org/en/info/mrcp. Accessed 19 May 2022.