# Gastrointestinal Manifestations in a Patient With Endolimax nana Infection: A Case Report

**Authors:** Mariana Castro, Joana Brandão Silva, Raquel Freitas, Ricardo Barbosa, João Beleza Bernardes

PMC · DOI: 10.7759/cureus.94840 · Cureus · 2025-10-18

## TL;DR

A 54-year-old woman with chronic diarrhea was found to have an Endolimax nana infection, which resolved after metronidazole treatment and avoiding contaminated water.

## Contribution

This case report highlights Endolimax nana as a potential cause of gastrointestinal symptoms and emphasizes the importance of water safety and targeted treatment.

## Key findings

- Endolimax nana cysts were identified in the patient's stool, and symptoms resolved after metronidazole treatment.
- Discontinuation of untreated well water consumption contributed to symptom resolution.
- Chronic diarrhea in individuals with untreated water exposure should prompt consideration of parasitic infections.

## Abstract

A 54-year-old female patient with a history of depressive disorder, previously treated and not currently on regular medication, lives in a rural area and regularly consumes untreated well water. She presented with a one-month history of abdominal pain, diarrhea, and tenesmus. Laboratory tests only revealed numerous Endolimax nana cysts in her stool, and endoscopic evaluation did not show significant findings. The patient's complete resolution of symptoms was achieved through the combined effect of metronidazole treatment and discontinuation of untreated well water consumption.

Endolimax nana is a generally non-pathogenic intestinal ameba, often found in untreated or contaminated water sources. However, it can be linked to gastrointestinal issues. Avoiding contaminated water is crucial for managing and preventing such infections. In cases of chronic diarrhea in people exposed to untreated water, doctors should consider parasitic infections in their differential diagnosis and start appropriate antimicrobial treatment based on the identified pathogen.

The following case report delineates the diagnostic and therapeutic strategies employed in a patient diagnosed with Endolimax nana infection.

## Linked entities

- **Chemicals:** metronidazole (PubChem CID 4173)
- **Diseases:** depressive disorder (MONDO:0002050), diarrhea (MONDO:0001673)

## Full-text entities

- **Diseases:** abdominal pain (MESH:D015746), chronic diarrhea (MESH:D003967), parasitic infections (MESH:D010272), Endolimax nana Infection (MESH:C535525), infections (MESH:D007239), depressive disorder (MESH:D003866)
- **Chemicals:** water (MESH:D014867), metronidazole (MESH:D008795)
- **Species:** Endolimax nana (species) [taxon 110788], Homo sapiens (human, species) [taxon 9606]

## Full text

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## Figures

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## References

13 references — full list in the complete paper: https://tomesphere.com/paper/PMC12534844/full.md

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Source: https://tomesphere.com/paper/PMC12534844