A 26-year-old man has had intermittent cramping abdominal pain and low-volume diarrhea for 3 weeks. On physical examination, he is afebrile; there is mild lower abdominal tenderness but no masses and bowel sounds are present. A stool sample is positive for occult blood. The symptoms subside within 1 week. Six months later, abdominal pain recurs with perianal pain. On physical examination, there is now a perirectal fistula. Colonoscopy shows many areas of mucosal edema and ulceration and some areas that appear normal. Microscopic examination of a biopsy specimen from an ulcerated area shows a patchy acute and chronic inflammatory infiltrate crypt abscesses, and noncaseating granulomas. Which of the following underlying disease processes best explains these findings?
The clinical and histologic features are consistent with Crohn disease, one of the idiopathic inflammatory bowel diseases. Crohn disease is marked by segmental bowel involvement and transmural inflammation that leads to strictures, adhesions, and fistula. Ulcerative colitis has mucosal involvement extending variable distances from the rectum. In contrast to Crohn disease, the mucosal involvement is diffuse and does not show "skip areas." Fissures and fistulas are not frequently seen in ulcerative colitis. The findings in Crohn disease and ulcerative colitis overlap, and at least 10% of cases it may be impossible to differentiate between them - so-called indeterminate colitis. Generally, crypt abscesses are more typical of ulcerative colitis, and granulomas are more typical of Crohn disease, but these features are not present in most biopsy specimens from patients with either condition. A story is told of an attending physician at an academic medical center who was known to berate students and residents on rounds for not definitively diagnosing ulcerative colitis and Crohn disease. When he retired, incomplete records for patients with idiopathic inflammatory bowel disease were found in his office; the records represented about one-sixth of the total cases of inflammatory bowel disease that he had seen. Amebiasis and shigellosis are infectious processes that can cause mucosal ulceration, but they do not produce granulomas or fissures. Sarcoidosis can involve many organs and give rise to noncaseating granulomas; however, the involvement of the intestines is uncommon, and sarcoidosis does not give rise to ulcerative disease.
Amebiasis
Crohn disease
Sarcoidosis
Shigellosis
G.I.T.