A 36-year-old man presents with cramping abdominal pain, urgency, bloody diarrhea, and weight loss. Physical examination reveals lowgrade fever, heme positive stools, and tenderness to palpation in the lower abdomen. Colonoscopy with biopsy is performed and the diagnosis of Crohn disease is made.
Which of the following findings is not associated with Crohn disease?
A. Loss of haustral markings (lead-pipe colon): Loss of haustral markings (lead-pipe colon). Distinguishing the two types of inflammatory bowel disease (IBD), Crohn disease and ulcerative colitis, is crucial to performing well on the gastroenterology questions on the medicine shelf examination. It is very difficult to determine the diagnosis simply from symptoms, although ulcerative colitis is more likely to be associated with bloody diarrhea and “cramping” abdominal pain, as opposed to the “colicky” pain often seen in Crohn’s. Given the nonspecific symptoms of IBD, a colonoscopy with biopsy is crucial to making the correct diagnosis. (B, C, D, E) Crohn disease is a chronic inflammatory bowel disease involving transmural (affecting the entire bowel wall) inflammation that can occur anywhere from the mouth to the anus (skip lesions). Crohn’s patients can present not only with lesions in the colon but also with lesions in the small bowel and even oral ulcers. Extraintestinal manifestations are common in Crohn disease as well, and include perirectal abscesses and fistulas. Biopsy in Crohn disease reveals noncaseating granulomas with mononuclear cell infiltrate. Ulcerative colitis, on the other hand, is associated with friable mucosa with ulcerations and erosions on colonoscopy; barium enema often reveals a lead-pipe colon with loss of haustra. Biopsy in ulcerative colitis reveals crypt abscesses and microulcerations (but no granulomas).