L:\usmle review 7 - Sinoe medical homepage.

14. A 25-year-old man presents to a rheumatologist with complaints of joint pain involving the
large joints of the legs. On questioning, the patient indicates that exacerbations in the joint pain
are frequently accompanied by diarrhea. Which of the following is the most likely diagnosis
(A)
(B)
(C)
(D)
(E)
Amebic colitis
Chronic appendicitis
Diverticulosis
Pseudomembranous colitis
Ulcerative colitis
14. The correct answer is E. Several gastrointestinal diseases are associated with
rheumatologic complaints. The most frequent of these are the chronic inflammatory bowel
diseases, ulcerative colitis, and Crohn disease, which can be associated with sacroiliitis (related
to HLA-B27) or lower limb arthritis. Other gastrointestinal diseases associated with arthropathy
include bypass surgery, Whipple disease, Behcet syndrome, and celiac disease.
Amebic colitis (choice A) is caused by ingestion of infectious cysts (typically from Entamoeba
histolytica). Symptoms include abdominal pain and diarrhea; malaise and weight loss also may
occur. Cecal amebiasis can resemble acute appendicitis.
Chronic appendicitis (choice B) may be asymptomatic or cause poorly defined abdominal pain.
Diverticulosis (choice C) is usually a disease of older adults. It is often asymptomatic unless
inflammation supervenes.
Pseudomembranous colitis (choice D) is a severe form of diarrhea usually seen in the setting of
prior antibiotic use. The causative organism is almost always Clostridium difficile.