Colonic involvement in patients with amebic liver abscess: endoscopic findings

Amebic liver abscess is the most common form of extraintestinal amebiasis. Although the parasite enters the liver via the portal vein after invading large bowel mucosa, only 15% to 30% of patients have diarrhea. This study was done to evaluate colonic involvement in patients with amebic liver abscesses.

In a prospective study, colonoscopy was performed in 50 patients with amebic liver abscesses and 15 control patients with acute amebic colitis. The findings were correlated with clinical features and ultrasonographic appearances.

Most patients with amebic liver abscesses presented with fever and abdominal pain. Complete examination of the colon was possible in 45 patients. Twenty six (58%) had evidence of lesions in the colon. Twenty-three of 45 (51%) patients had a few discrete, small ulcers restricted to the right side of colon. Three of 45 (7%) patients with liver abscesses, who also had diarrhea at presentation, had larger and more numerous ulcers with inflammation of the surrounding mucosa of the left colon. Control patients with amebic colitis presented with diarrhea. Endoscopically, they all had multiple large ulcers with diffuse inflammation of the intervening mucosa of the left colon, similar to that seen in patients with liver abscess having diarrhea.

Colonic involvement is common in patients with amebic liver abscess but most patients do not suffer from diarrhea, possibly because of very limited extent of the pathology that is confined mainly to the right side of colon.