Invasive amebiasis in the colon

Dr. Ulrike Schempf and Dr. Dörte Wichmann
Interdisciplinary Endoscopy Unit, Tübingen University Hospital

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Patient history, clinical findings?

A 73-year-old man presented in otherwise good general condition, reporting recurrent bouts of fever and right-sided abdominal pain over the few previous days. The patient’s history showed that he had been in India a few months before this event, where he had contracted a feverish diarrheal infection.

Laboratory

There was a pattern of acute inflammation with 17210 leukocytes/µL and a CRP of 6.7 mg/dL. AP was slightly raised at 162 U/L, ?GT was raised at 219, and the bilirubin level was normal. A complete blood count showed raised monocytes (11070/µL) and neutrophils (13180/µL).

Imaging

Fig. 1: Angio-CT of the epigastric region, with a large hepatic abscess

Microbiology

The serology findings were positive for Entamoeba histolytica IgG. The fecal samples initially taken to test for E. histolytica were negative.

Course

Three days after placement of the abscess drain, the patient developed Hb-relevant and circulation-relevant lower gastrointestinal bleeding. Images from the emergency colonoscopy are shown in Figs. 2–4. Several ulcerations without acute bleeding stigmata were detected in the ascending colon in the immediate vicinity of the ileocecal valve. The terminal ileum had no ulcerations and was free of blood. The repeat fecal samples then taken were positive for E. histolytica (with evidence of cysts in the feces).

Endoscopy

Summary

The patient had contracted invasive amebiasis.

Interesting facts about amebiasis:

Pathogen

The parasite Entamoeba histolytica, an intestinal protozoon, trophozoite (vegetative, not infectious) or cystiform (large or minute form, infectious, sometimes invasive).

Transmission/infection

contaminated food

Incidence

tropical and subtropical regions

Course:

1. Asymptomatic course (90% of cases); affected individuals are symptom-free carriers.
2. Invasive amebiasis; development of ulcerations and intestinal abscesses; typical finding: feces with raspberry jelly appearance.
3. Extraintestinal amebiasis; abscess formation in the liver (95%) or other organs.

Frequency

the WHO estimates the annual numbers of incident cases at 50,000, with up to 110,000 deaths per year.

Mortality

Approximately 1%

Treatment

Intravenous or oral metronidazole in cases of invasive amebiasis persisting for more than 10 days, and in case of intestinal infection one-stage or two-stage eradication with paromomycin 3 × 500 mg/d for 10 days.

Reference

Deutsche Gesellschaft für Tropenmedizin und Internationale Gesundheit. S1-Leitlinie Diagnostik und Therapie der Amöbiasis. Überarbeite Version Oktober 2018. Berlin: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF), 2018. Available at: https://www.awmf.org/leitlinien/detail/ll/042-002.html (accessed 29 May 2019).