A 25-year-old woman with sickle cell anemia complains of steady pain in her right upper quadrant with radiation to the right shoulder, especially after large or fatty meals. Her physician diagnoses gallstones. Of which of the following compounds are these stones most likely composed?
**Core Concept**
Sickle cell anemia is a genetic disorder characterized by the production of abnormal hemoglobin (HbS), which can lead to the formation of sickled red blood cells. These cells are more prone to damage and can cause increased bilirubin production, leading to an increased risk of cholesterol gallstones.
**Why the Correct Answer is Right**
Gallstones in patients with sickle cell anemia are often pigment stones, primarily composed of calcium bilirubinate. This type of stone forms when bilirubin, a byproduct of red blood cell breakdown, is converted into calcium bilirubinate. This compound is more likely to precipitate out of solution and form stones in the gallbladder. The increased risk of gallstones in patients with sickle cell anemia is thought to be related to the increased bilirubin production due to the chronic hemolysis associated with the disease.
**Why Each Wrong Option is Incorrect**
**Option A:** Cholesterol stones are more common in the general population but are less likely to be associated with sickle cell anemia. They are typically composed of cholesterol and other substances that precipitate out of solution in the gallbladder.
**Option B:** Calcium carbonate stones are typically seen in patients with conditions that cause an excess of calcium in the body, such as hyperparathyroidism. They are not typically associated with sickle cell anemia.
**Option C:** Calcium phosphate stones are often seen in patients with conditions that cause an excess of phosphate in the body, such as kidney disease. They are not typically associated with sickle cell anemia.
**Clinical Pearl / High-Yield Fact**
It's essential to consider the patient's underlying medical conditions when diagnosing gallstones. Sickle cell anemia is just one example of a condition that can increase the risk of gallstones. Other conditions, such as primary biliary cirrhosis and inflammatory bowel disease, can also increase the risk of gallstones.
**Correct Answer:** C. Calcium bilirubinate.