Which of the following is a common complication of Crohn's disease?

Fistulas are a common complication of Crohn's disease due to the nature of the disease itself, which is characterized by inflammation that can penetrate the entire wall of the gastrointestinal tract. This chronic inflammation can lead to the development of abnormal connections, or fistulas, between different parts of the intestine or between the intestine and other organs, such as the bladder or skin. These fistulas can be symptomatic and may require medical or surgical intervention.

In contrast, diverticulitis, gastroesophageal reflux, and esophageal varices are conditions that are either not directly associated with Crohn's disease or are more commonly related to other underlying factors or disorders. For instance, diverticulitis typically arises from diverticulosis, which occurs more frequently in older populations and is related to constipation and low-fiber diets. Gastroesophageal reflux disease (GERD) generally stems from issues related to the esophagus and is more associated with lifestyle factors. Esophageal varices are complications related primarily to portal hypertension, often due to liver disease, rather than being a direct consequence of Crohn's disease.