Certified Neuroscience Registered Nurse (CNRN) Practice Exam

What is the most common type of gallstone that is caused by undissolved cholesterol?

1. Mixed gallstones

2. Pigmented gallstones

3. Cholesterol gallstones

4. Black gallstones

The correct answer is: Cholesterol gallstones

Cholesterol gallstones are the most prevalent type of gallstones, accounting for approximately 80% of cases. These stones form when there is an imbalance in the substances that comprise bile, particularly when there is an excess of cholesterol that becomes undissolved. When cholesterol levels exceed the solubilizing capacity of bile salts and phospholipids, it can precipitate and crystallize, ultimately leading to the formation of gallstones. Cholesterol gallstones are typically yellowish-green in color and can vary in size from very small to large, potentially causing blockages or inflammation in the biliary tract. These stones are most commonly associated with obesity, diabetes, and conditions that affect bile composition. Understanding this context highlights the significance of cholesterol saturation in gallstone formation, distinguishing them clearly from mixed gallstones or pigmented gallstones. Mixed gallstones, as the name suggests, are composed of both cholesterol and other components, while pigmented gallstones primarily consist of bilirubin and are often associated with conditions such as hemolysis or cirrhosis. Black gallstones, a subset of pigmented stones, specifically arise from excess bilirubin and are not related to cholesterol levels. Thus, cholesterol gallstones represent the primary type formed through undiss