All of the following are potential causes of appendix obstruction and appendicitis EXCEPT:
A. Ascaris infection
B. Carcinoid tumor
E. Measles infection
The answer is C. (Chap. 356) Obstruction of the appendiceal lumen is believed to typically result in appendicitis. Although obstruction is most commonly caused by fecalith, which results from accumulation and inspissation of fecal matter around vegetable fibers, other causes have been described. These other potential causes include enlarged lymphoid follicles associated with viral infection (e.g., measles), inspissated barium, worms (e.g., pinworms, Ascaris, and Taenia), and tumors such as carcinoma or carcinoid. Cholelithiasis is a common cause of acute pancreatitis.