Massive gastrointestinal bleeding in fulminant amebic colitis: a case report

BACKGROUND: Amebiasis, caused by Entamoeba histolytica, remains a major global health concern, particularly in developing regions. While most infections are asymptomatic, a small subset may progress to fulminant amebic colitis (FAC), a rare but life-threatening condition. Massive lower gastrointestinal (GI) bleeding is an exceptionally uncommon manifestation of FAC. CASE PRESENTATION: We report a rare case of a 27-year-old Iranian male with no prior medical history who presented with fever, right upper quadrant abdominal pain, and diarrhea, later complicated by hematochezia exceeding one liter. Imaging revealed liver abscesses and cecal wall thickening. Emergency laparotomy confirmed active cecal bleeding and liver abscesses. A right hemicolectomy with ileocolic anastomosis and abscess drainage was performed. Histopathology revealed flask-shaped ulcers and reactive lymphadenopathy, confirming amebic colitis. Postoperative recovery was uneventful with resolution of symptoms following metronidazole and paromomycin therapy. CONCLUSIONS: This case underscores the diagnostic challenges of FAC, especially in patients lacking typical risk factors. Conventional stool and serologic tests may be inconclusive in acute settings. Advanced imaging and histopathology remain pivotal for diagnosis. The pathophysiology involves mucosal invasion and vascular erosion by E. histolytica trophozoites, leading to hemorrhage. Integrated surgical and antimicrobial management is essential for favorable outcomes. Massive GI bleeding in amebic colitis is rare but potentially fatal. Early recognition, prompt imaging, and combined surgical-medical intervention can significantly improve prognosis, even in young patients without predisposing conditions.