Definition

Cholelithiasis, or gallstone in the bile duct, refers to the formation of one or more stones in the bile duct. Bile duct stones can either form in the gallbladder or directly in the bile duct.

The common bile duct is a small passage from the liver that carries bile from the gallbladder into the small intestine, aiding in fat digestion. The gallbladder is a pear-shaped organ located under the liver on the upper right side of the abdomen. Gallstones typically stay in the gallbladder or pass through the bile duct. They are commonly composed of bile pigments, calcium, or cholesterol.

When gallstones are present in the bile duct, they can obstruct bile flow into the small intestine, causing it to back up into the liver. Studies indicate that approximately 1-15% of people with gallbladder stones may also develop cholelithiasis or bile duct stones.

Causes

Gallstones can be classified into two main types based on their composition: pigment stones and cholesterol stones. Cholesterol stones are the most common type and are often yellow. These stones form due to bile containing an excess of cholesterol, an abundance of bilirubin (a yellow pigment resulting from the breakdown of red blood cells), and insufficient bile salts.

Cholesterol gallstones tend to develop when the gallbladder fails to empty completely or frequently enough. They are commonly found in obese individuals who engage in infrequent physical activity or in people who intentionally undergo rapid weight loss.

Pigment gallstones are dark stones categorized into two subtypes: pure pigment stones and brown pigment stones. Pure pigment stones consist mainly of pigment, while brown pigment gallstones are formed by a combination of pigment and bile fats. The exact cause of the formation of pigment gallstones is not fully understood.

Pigment gallstones often develop in individuals with certain conditions, including:

• Liver cirrhosis or the presence of scar tissue on the liver.
• Bile duct infections, where bacteria are a source of brown pigment for the stones.
• Those receiving nutritional support intravenously for an extended period, often in hospitalized patients.
• Individuals who have undergone intestinal resection or the removal of a portion of the intestine.
• Hereditary blood disorders that cause the liver to produce an excess of bilirubin.

Choledocholithiasis can be induced by cholangitis, which is inflammation of the gallbladder. A recovered gallbladder may develop scar tissue, leading to bile stagnation and sedimentation in the gallbladder.

Based on their origin and formation mechanisms, gallstones in the bile ducts are classified as follows:

• Primary stones: Typically, brown pigment stones formed directly in the bile ducts.
• Secondary stones: Usually, cholesterol stones form in the gallbladder and later migrate to the bile ducts.
• Residual stones: Stones left behind after gallbladder removal performed within the last 3 years.
• Recurrent stones: Occur in ducts that have undergone surgery more than 3 years ago.

Risk factor

Individuals with a history of bile stones or gallbladder disease are at risk of developing bile duct stones. Even those with a removed gallbladder can experience bile duct stones in 4.6% to 18.8% of cases. Some risk factors are modifiable through lifestyle changes, and addressing these factors can reduce the risk of bile duct stones.

Several factors that may increase the risk of developing gallstones in the bile ducts include:

• Obesity
• Low-fiber, high-calorie, high-fat diet
• Pregnancy
• Prolonged fasting
• Rapid weight loss
• Lack of physical activity
• High blood cholesterol levels

Unmodifiable risk factors include:

• Age: Older adults are generally at a higher risk of developing gallstones.
• Gender: Women are more likely to have gallstones.
• Ethnicity: Individuals of Asian, Indian-American, and Mexican-American descent have a higher risk of gallstones.
• Family history: Genetic factors are believed to play a role in the occurrence of gallstones in the bile ducts.

Symptoms

Bile duct stones can remain asymptomatic for months or even years. However, when a stone becomes lodged and obstructs the flow of bile, various symptoms may arise, including:

• Severe abdominal pain in the upper right or upper middle side.
• Fever.
• Jaundice is characterized by yellowish skin or eye sclera.
• Loss of appetite.
• Nausea and vomiting.
• Pale stool.

The abdominal pain may be intermittent, with episodes of pain followed by periods of relief, or it can be persistent and severe. Severe pain may require emergency medical attention. In some cases, the pain might be mistaken for a heart attack.

Diagnosis

When symptoms suggest the presence of gallstones in the bile duct, doctors will employ various imaging tests to confirm the diagnosis. These may include:

• Abdominal Ultrasound (USG): Utilizes high-frequency sound waves to examine the liver, gallbladder, spleen, kidneys, and pancreas.
• Abdominal CT Scan: Provides detailed cross-sectional images of the abdomen.
• Endoscopic Ultrasound (EUS): Involves inserting an ultrasound probe into a flexible endoscope, which is then passed through the mouth to examine the digestive tract.
• Endoscopic Retrograde Cholangiography (ERCP): Identifies stones, tumors, and narrowing of the bile ducts.
• Magnetic Resonance Cholangiopancreatography (MRCP) or MRI: Examines the gallbladder, bile ducts, and pancreas.
• Percutaneous Transhepatic Cholangiogram (PTCA): An X-ray imaging procedure for the bile ducts.

Blood tests are also essential for further evaluation, checking for signs of infection, and assessing the function of the liver and pancreas. These may include:

• Complete Blood Test
• Bilirubin Test
• Pancreatic Enzymes
• Liver Function Tests such as SGOT and SGPT

Management

The primary focus of treatment for gallstones in the bile duct is to eliminate the blockage. Various treatment options are available, including:

• Gallstone Extraction: Removing the gallstones from the bile duct.
• Lithotripsy (Stone Breakage): Breaking down the stones into smaller fragments, making it easier for them to pass through the duct.
• Cholecystectomy (Gallbladder Removal): Removal of the gallbladder and the stones.
• Sphincterotomy: Excision of the bile duct or the sphincter to facilitate the passage of stones.
• Installation of Stent or Ring: Place a stent or ring in the bile duct to keep it open.

The most common treatment is Biliary Endoscopic Sphincterotomy (BES). If the stone cannot pass naturally or be extracted through BES, lithotripsy may be considered. This procedure involves breaking the stones into smaller fragments for easier passage.

Gallbladder removal can also treat gallstones. After the surgery, the doctor will check for any remaining stones in the bile duct. If complete extraction is not possible or the gallbladder is not removed, a stent may be installed to keep the bile duct open. This procedure not only facilitates bile passage and prevents recurrence but also helps prevent infections.

Complications

Gallstones, when lodged in the gallbladder, can lead to severe complications. Obstruction caused by gallstones can result in bile infection, where bacterial growth occurs, potentially spreading to the liver and causing a life-threatening condition. Prolonged obstruction may lead to biliary cirrhosis, characterized by scar tissue formation in the liver. Gallstone-related inflammation in the bile ducts, known as cholangitis, can hinder bile flow, and the backup of bile into the pancreatic duct may cause pancreatitis. In severe cases, widespread infection can lead to sepsis, a serious systemic inflammatory response.

Prevention

If gallstones have been identified in the bile duct, there is a risk of recurrence even after gallbladder removal. Adopting lifestyle changes, such as engaging in regular moderate exercise, maintaining a high-fiber diet, and limiting the consumption of saturated fats, can help reduce the likelihood of gallstone recurrence. These measures contribute to overall digestive health and may lower the risk of stone formation in the bile duct.

When to see a doctor?

Suppose you experience abdominal pain with or without fever and the cause is unidentified, such as jaundice (yellowing of the skin or eyes) or symptoms associated with choledocholithiasis. In that case, it is advisable to consult a doctor.

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