Abdominal cramping develops in a 31-year-old healthy woman after she runs a marathon. She has the urge to have a bowel movement and then passes some bright red blood. A colonoscopy performed the next day demonstrates focal colitis characterized by shallow ulcers, erythema, and friability from the sigmoid to the descending colon.
Which of the following is most likely?
a. The ulcers will resolve within 48 hours.
b. The patient uses an intrauterine device (IUD) for contraception.
c. This is the initial presentation of Crohn disease.
d. The patient should be tested for cytomegalovirus (CMV).
Correct answer: A
Ischemic colitis developed in this patient after a marathon because of shunting of blood away from the bowels to the muscles. The most affected area is the watershed portion of the colon, which includes the area around the splenic flexure and left colon. Ischemic colitis can range from mild with shallow ulcerations to complete necrosis of bowel. The majority of the cases that occur in marathon running are mild and self-limited with supportive care. Another risk factor for colonic ischemia in younger patients is medications, including illicit drugs (cocaine) and prescribed medications (phenylephrine) as well as estrogen-containing oral contraceptives. IUDs do not generally contain estrogen and therefore are not considered a risk factor for ischemic bowel disease. Inflammatory bowel disease can certainly present with abdominal cramping, hematochezia, and focal colitis. Although these findings would be more suggestive of ulcerative colitis than of Crohn disease, the temporal association with marathon running would make ischemic colitis more likely. CMV colitis usually occurs in the presence of a systemic illness and in immunocompromised patients.