A rare and potentially fatal complication of amoebiasis: acute fulminant necrotizing amoebic colitis

Abstract

A 65-year old male was admitted to surgical casualty with symptoms and signs of acute intestinal obstruction. He has been a toddy drinker for more than twenty years. Distended small and large bowel shadows were noted on the supine abdominal x-ray and inflammatory markers were elevated in blood. He underwent emergency laparotomy; descending colon and proximal part of sigmoid colon were found to be necrotic, with multiple perforations and a loculated abscess in the left paracolic gutter. The necrotic bowel loops were resected and the viable distal sigmoid colon was closed and an end colostomy was created. Macroscopically, specimen consisted of pieces of large bowel, measuring up to 15 cm in length and 6 cm in diameter, with patchy areas of full-thickness soft, white necrosis of the wall, ulcers with necrotic material adherent to their bases and large perforations (Figure 1). The ulcers were typically flask shaped, with a narrow neck and broad, undermined base. Microscopically, the affected bowel wall showed ischaemic necrosis with a mixed inflammatory cell infiltrate and small clusters of dispersed amoebic trophozoites (Figure 2 and 3). Periodic Acid Schiff staining was positive. The necrosis was transmural in the areas of perforation, and amoebic trophozoites were also seen within the lumen of blood vessels. Figure 2. H & E (4x10) Part of a flask shaped ulcer with undermined edges. Figure 1. A segment of colon showing mucosal ulcers with slough on the surface. Figure 3. H & E (40x10) amoebic trophozoites with ingested red blood cells (arrow) in a necrotic background.