Fig. 1.40 Complications of amebiasis. (From Ash and Spitz: Pathology of Tropical Diseases. Philadelphia, Saunders).

Complications (Fig. 1.40)

There are several major complications of colonic amebiasis, some of which are specific circumstances that demand a laparotomy, eg, intussusception or other suspected obstruction, or perforation or appendicitis leading to peritonitis.

Intussusception. Children with amebic colitis may present to the radiologist as intussusception, and the diagnosis may not be realized until the barium enema is under way (Figs. 1.41 and 1.42). Although the bowel wall in such cases is ulcerated, perforation is uncommon and reduction of the intussusception by enema should be preferable to surgical treatment, because the bowel will be extensively inflamed far beyond the intussusception. Amebomas are uncommon in children, but they can form a mass which may become the origin of an intussusception.

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Fig. 1.41 Amebiasis with intussusception of an ameboma in a child from San Salvador. (A and B) Note the typical "coiled spring" appearance of the colon from an intussusception in the distal descending colon. There are globules of barium outside the colon secondary to an associated perforation causing a transmural peritonitis. (C) A plain film of the abdomen taken 2 days later, shortly before the child died, shows the mass in the left lower quadrant representing the unreduced intussusception, as well as scattered flecks of barium throughout the peritoneal cavity from the perforation. The proximal colon and multiple loops of small bowel are markedly distended as a result of the obstructing intussusception and transmural peritonitis. (Courtesy of Dr. Julio Astacio, San Salvador).

Fig. 1.42 (A-C) lntussusception in amebic colitis in a 4-year-old African girl. She had acute abdominal pain, vomiting, pyrexia, and blood in the stools. There was a palpable mass in the left lower quadrant, and a clinical diagnosis of intussusception was made. Barium enema (A) revealed ulceration and narrowing of the rectosigmoid colon. Further progress of the barium column revealed a prominent, long filling defect with the coiled spring appearance typical of intussusception (B and C). This colocolic intussusception was reduced to the cecum. Radiological reduction of an amebic intussusception is somewhat dangerous because of the risk of perforation of the bowel, but surgery can be even more hazardous because of the risk of spread of the amebic infection in the presence of the existing untreated amebic colitis. (D) lntussusception at the level of the hepatic flexure caused by an ameboma in an adult man from Zimbabwe.