American Board of Internal Medicine (ABIM) Certification Practice Exam

What is a common cause of secretory diarrhea?

1. Carbohydrate malabsorption

2. Clostridium difficile infection

3. Medications such as colchicine

4. Pancreatic insufficiency

The correct answer is: Medications such as colchicine

Secretory diarrhea is characterized by the active secretion of electrolytes and water into the intestinal lumen, regardless of food intake. This type of diarrhea persists even during fasting and is often due to infections, toxins, or certain medications. Medications like colchicine can induce secretory diarrhea as a side effect. Colchicine, primarily used for gout and Familial Mediterranean Fever, can irritate the intestinal lining and lead to increased secretion of fluid. This mechanism of action can directly contribute to a state of secretory diarrhea. Other conditions typically associated with diarrhea, such as carbohydrate malabsorption, Clostridium difficile infection, and pancreatic insufficiency, generally lead to different types of diarrhea. For example, carbohydrate malabsorption leads to osmotic diarrhea, which occurs when unabsorbed solutes in the gut attract water into the intestinal lumen. Clostridium difficile infection often causes inflammatory diarrhea due to toxins produced by the bacteria, which can lead to colitis, while pancreatic insufficiency mostly results in fatty or steatorrhea due to the malabsorption of fats, rather than secretory diarrhea per se.