Abstract:

Objective To analyze the clinical and endoscopic characteristics of 10 cases of amoebic colitis. Methods Data on 10 cases of amoebic colitis diagnosed in a tertiary hospital in Beijing from May 2021 to May 2024 was collected, including clinical manifestations, blood routine, stool routine, liver and kidney function, endoscopic mucosal features of colonic lesions, pathological features, treatment and prognosis, to summarize the clinical and endoscopic characteristics of amoebic colitis. Results All 10 patients were male, with an average age of (37.8 ± 13.1) years, ranging from 28 to 70 years among them, 4 cases had a history of sexually transmitted disease [3 cases of human immunodeficiency virus (HIV) infection, 1 case of syphilis], 1 case had a history of hepatitis C, and 1 elderly patient had a history of hypertension. Clinical symptoms include changes in defecation habits and stool shape, manifested as diarrhea and bloody stools, with 8 patients experiencing abdominal pain. All cases had mild tenderness in the abdomen. Blood routine and lymphocyte count were both normal, with only one patient having an increased proportion of eosinophils (13.4%). No amoebic cysts were found in the stool routine, and occult blood was positive in the stool. Eight patients had positive red blood cells and white blood cells in the stool, while two patients had negative results for both. Renal function was normal, and 9 patients had normal liver function and bilirubin levels. Only one patient with amoebic liver abscess had elevated bilirubin levels (total bilirubin 50 μmol/L, direct bilirubin 37.5 μmol/L). The endoscopic examination showed that the lesions in 10 patients mainly affected the ileocecal, ascending colon, and rectum segments, all presenting as scattered and irregular map-like ulcers, numbered in dozens and sized 5-30 mm in diameter. The surface of the ulcer was covered with a yellow or white coating, and the white coating overflows from the ulcer surface. The surrounding mucosa of the ulcer was congested, edematous and bloody, and the intestinal mucosa between the ulcers was normal. Among them, three cases with HIV-coinfection had larger ulcer areas. The hematoxylin-eosin staining showed that all 10 patients’ intestinal mucosal biopsy sections displayed inflammatory granulation tissue, a large amount of eosinophil and neutrophil infiltration in stroma, and amoeba trophozoites in inflammatory necrotic tissue and on mucosal surface. Among the ten patients, nine were given metronidazole (750 mg each time, 3 times a day) and diloxanide (500 mg each time, 3 times a day) orally for 10 days. One patient with amoebic colitis complicated with liver abscess was treated with intravenous injection of metronidazole (500 mg each time, once every 8 hours) for 14 days and then switched to oral metronidazole (750 mg each time, three times a day) for 10 days. After treatment, clinical symptoms such as abdominal pain, diarrhea, bloody stools, and purulent stools were significantly relieved in 10 patients. Among them, 6 patients had no abnormalities in routine stool examination and occult blood, and 2 patients had normal colon mucosa lesions on colonoscopy. Conclusion Amoebic colitis is more common in males, often seen in those with complicated sexually transmitted diseases. Clinical symptoms often include changes in bowel habits and hemafecia. Under endoscopy, the lessions mainly involve the ileocecal region, ascending colon, and rectum, presenting as ulcers of varying sizes. Diagnosis could be confirmed by finding of amoeba trophozoites in pathological biopsy.

Key words: Amoebic colitis, Clinical features, Endoscopic features, Pathological diagnosis