Colon

Barium enema studies, using diluted barium and without colon cleansing, reveal a decrease in the number and depth of the haustra or their complete disappearance. Poor contractility and emptying ability of the colon are also noted (Figs. 4.19 and 4.20). A hive-like mucosal pattern (urticarial wheal or intestinal hives) is occasionally seen within a portion of the dilated colon, probably due to chronic obstipation and stasis ulceration of the mucosa from chronic fecal impactions or due to hypersensitivity or autoimmune phenomenon (Fig. 4.21); rarely a diffusely ulcerated bowel may complicate Chagas' megacolon (Fig. 4.22).

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Fig. 4.19 Chagas' megacolon in a 56 year-old Brazilian woman with chronic obstipation. The anteroposterior (A), oblique (B) and lateral (C) views from a barium enema show massive dilatation of the entire rectosigmoid colon. Note the large fecaliths within the colon. The distal rectum is not dilated to the same degree as the sigmoid and descending colon because of the action of the pelvic musculature. A follow-up plain film of the abdomen taken 47 days later showed marked retention of barium from this examination (D). The patient had only a scanty bowel movement in the interval. (Courtesy of Dr. Clovis Simao).

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Fig. 4.20 Chronic Chagas' disease with megacolon in a Brazilian man. Oblique (A) and lateral (B) views show marked dilatation of most of the colon, especially the sigmoid colon which is also somewhat elongated and redundant. The lower rectum is not dilated to the same degree as the sigmoid and descending colon because of the rigidity of the musculature of the pelvic floor. Loss of tone throughout the involved colon could be seen fluoroscopically. The patient had intestinal constipation beginning 5 years previously with bowel movements every 2-3 days. At the time of this barium enema he was defecating every 12 days but had no colic. His feces were dry and he needed a laxative for intestinal function. His Chagas' serology was positive. (Courtesy of Dr. Clovis Simao).

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Fig. 4.21 Chagas' megacolon with hive-like appearance of the mucosa in two Brazilian men. (A) There is severe distention and elongation of the rectum, sigmoid and descending colon with normal caliber of the proximal colon. The hive-like mucosal pattern in the rectum is probably secondary to chronic obstipation with fecal impactions and stasis ulcerations but the pattern is similar to that seen with mucosal hives caused by a hypersensitivity or autoimmune phenomenon. The grossly dilated sigmoid colon extends to the level of the left hemidiaphragm, and plain film examination of the chest showed marked distention of the colon, elevating the left hemidiaphragm and simulating the splenic flexure syndrome. (B) A similar hive-like pattern is seen in a grossly dilated and redundant sigmoid colon of another Brazilian, a 61 year-old black man, who had had constipation for 10 years. During that time, he had bowel movements every 2-3 days and, more recently, every 5-7 days with the use of laxatives. (Courtesy of Dr. Clovis Simao, Sao Paulo).

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Fig. 4.22 Chagas' megacolon in a Brazilian adult showing numerous superficial ulcerations throughout a somewhat narrowed proximal sigmoid colon. There is a tubular appearance to this portion of the sigmoid and loss of all haustral markings. The distal sigmoid and rectum are grossly distended. (A) AP view of barium enema taken after filling of the colon with barium and air. (B) Postevacuation film from the air contrast barium enema shows a hive-like mucosal pattern in the rectosigmoid colon and diffuse superficial ulcerations. Some cases of megacolon show diffuse inflammatory changes and ulcerations within the involved segment of bowel, primarily as a result of prolonged fecal stasis and impactions.