What is the Difference Between Cholesterol and Pigment Gallstones

The main difference between cholesterol and pigment gallstones is that cholesterol gallstones are yellow-green in color and made up of mostly hardened cholesterol, whereas pigment gallstones are dark in color and made up of bilirubin. 

Cholesterol and pigment gallstones are two types of gallstones (cholelithiasis) that form in the gallbladder. They are hard, pebble-like pieces of material. There can be one or hundreds of tiny stones in the gallbladder.

Key Areas Covered

1. What are Cholesterol Gallstones
     – Definition, Formation, Importance
2. What are Pigment Gallstones
     – Definition, Formation, Importance
3. Similarities Between Cholesterol and Pigment Gallstones
     – Outline of Common Features
4. Difference Between Cholesterol and Pigment Gallstones
     – Comparison of Key Differences

Key Terms

Cholesterol Gallstones, Pigment Gallstones

What are Cholesterol Gallstones

Cholesterol gallstones are one of the two types of gallstones that can occur in the gallbladder. They are the most common type of gallstones. Generally, 80% of gallstones are cholesterol gallstones. The formation of cholesterol gallstones occurs due to the cholesterol saturation in bile. This type of gallstone consists of hardened cholesterol. Other substances like calcium carbonate also occur in cholesterol gallstones. Typically, the color of cholesterol gallstones is yellow-green.

Figure 1: Cholesterol Gallstones, Mixed Gallstones, and Pigment Gallstones  

Furthermore, cholesterol gallstones are solitary and oval, while their size is 2 to 3 cm. Each of the cholesterol gallstones contains a tiny dark central spot. They contain 80% cholesterol by weight. Apart from that, mixed stones contain 20-80% of cholesterol. In general, they are brown pigment stones. Predominantly, cholesterol stones occur in women and obese people. They are also commonly associated with obstruction and inflammation.

What are Pigment Gallstones

Pigment gallstones are the other type of gallstones that occur in the gallbladder. However, they are less common. The formation of pigment gallstones is due to the presence of conjugated or unconjugated bilirubin in bile. Normally, bilirubin forms when the liver breaks down red blood cells. The liver produces increased levels of bilirubin in conditions including liver cirrhosis, biliary tract infections, and in certain blood disorders. Generally, extra bilirubin combines with calcium salts to form pigment gallstones. Therefore, pigment gallstones are calcium bilirubinate gallstones.

Figure 2: Gallstones

The color of pigment gallstones is brown or black. Generally, black pigment stones consist of pure calcium bilirubinate or complexes of calcium, copper, and mucin glycoproteins. The formation of black pigment gallstones occurs in conditions of stasis, for example, in parenteral nutrition and excess conjugated bilirubin or in hemolysis or cirrohosis. Moreover, black pigment gallstones are likely to remain to stay in the gallbladder. Meanwhile, brown pigment gallstones contain calcium salts of unconjugated bilirubin with small amounts of cholesterol and protein. They usually occur in bile ducts and cause obstruction in conditions with infected bile.    

Similarities Between Cholesterol and Pigment Gallstones

• Cholesterol and pigment gallstones are two types of gallstones that can occur in the gallbladder.
• They are hard, pebble-like pieces of material.
• The size of a gallstone can range from a grain of sand to a golf ball.
• There can be one large gallstone to hundreds of tiny stones.
• Gallstones can block the bile ducts of the biliary tract.
• They can also cause inflammation.

Difference Between Cholesterol and Pigment Gallstones

Definition

Cholesterol gallstones refer to the most common type of gallstones that often appear yellow in color, while pigment gallstones refer to any dark brown-to-black stones consisting of calcium salts of bilirubin.

Made up of

Cholesterol gallstones are made up of hardened cholesterol, while pigment gallstones are made up of calcium salts of bilirubin.

Occurrence

Moreover, cholesterol gallstones are more common, while pigment gallstones are less common.

Causes

Cholesterol gallstones occur due to cholesterol saturation, while pigment gallstones occur due to the presence of much-conjugated bilirubin or unconjugated bilirubin.

Color

Cholesterol gallstones are yellow-green in color, while pigment gallstones are brown to black in color.

Conclusion                                                

In brief, cholesterol and pigment gallstones are two types of gallstones that occur in the gallbladder. Generally, cholesterol gallstones are made up of hardened cholesterol. They are the most common type of gallstones that occur due to cholesterol saturation. In addition, the color of cholesterol gallstones is yellow-green. In comparison, pigment gallstones are a less common type of gallstone made up of calcium salts of bilirubin. Generally, they occur due to the presence of much conjugated or unconjugated bilirubin. Apart from that, the color of pigment gallstones is brown to black. Therefore, the main differences between cholesterol and pigment gallstones are their color, occurrence, and causes.   

References:                

1. “Gallstones.” NHS choices. Retrieved January 30, 2023

Image Courtesy:

1. “Types of Gallstones” By Scientific Animations – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Gallstones” By BruceBlaus – Own Work (CC BY-SA 4.0) via Commons Wikimedia