Clinical Case Summary

Introduction: Amebiasis is not a diagnosis of endemic regions anymore. It should be included in the list of differential diagnoses of erosive and ulcerative changes of the intestine.
Case presentation: A 38-year-old woman came to a gastroenterologist because of flatulence and abdominal cramping during the past two years. In 2019 the patient was urgently hospitalized in a surgical department with suspicion of appendicitis. Ultrasound found a thickening wall of the caecum and appendix without laboratory abnormalities. After symptomatic treatment, the patient underwent ileocolonoscopy: aphthous changes of mucosa were in the transverse colon. Undifferentiated colitis was diagnosed. A pharmacological therapy with 5-aminosalicylic acid was initiated. In 2021 the ileocolonoscopy underwent again because there was no effect of treatment: mucosal ulcerations of the caecum and ascending colon. The biopsy and stool examination (a method of formalin-ether sedimentation) showed Entamoeba hystolytica. Metronidazole was the drug of choice with a good clinical effect in this case. But three months later, the symptoms returned. It was the first relapse with positive results in feces analysis. The second line of therapy was tinidazole. Again, three months after, she had a relapse in laboratory tests. Ultrasound showed a wall thickening in the caecum and ascending colon. We achieved long-term clinical and endoscopic remission only after treatment with paromomycin (not registered in Russian Federation).
Discussion: Due to a large amount of travel to endemic regions, protozoal infections are not a problem in developing countries. Infectious lesions of intestine mucosa often mimic inflammatory bowel disease. It leads to late diagnosis, incorrect treatment, and complications.
Conclusion: This case outlines the difficulty of diagnosing and treating chronic protozoal infection because of the absence of characteristic symptoms.
Disclosure: Nothing to disclose.

References

1. Gomes Tdos S, Garcia MC, de Souza Cunha F, et al. Differential diagnosis of Entamoeba spp. in clinical stool samples using SYBR green real-time polymerase chain reaction. Thescientificworldjournal. 2014 ;2014:645084. DOI: 10.1155/2014/645084. PMID: 24693242; PMCID: PMC3944400.
2. Yue, B., Meng, Y., Zhou, Y. et al. Characteristics of endoscopic and pathological findings of amebic colitis. BMC Gastroenterol 21, 367 (2021). https://doi.org/10.1186/s12876-021-01941-z
3. Herrera, G. C., Herrera, A. C., Pontón, P. et al. (2019). Amebiasis, a rare cause of acute appendicitis. Journal of surgical case reports, 2019(3), rjz076. https://doi.org/10.1093/jscr/rjz076
4. Kafadar, M.T., Bakan V., Çaviş T. (2017). Chronic amebiasis presenting as appendicitis and preliminary diagnosed as a mucocele: A diagnostic dilemma and unexpected histopathological finding after surgery. https://doi.org/10.5505/VTD.2017.71463 Corpus ID: 54639273
5. Richard D. Pearson MD, University of Virginia School of Medicine Overview of intestinal Protozoan and Microsporidia infection, 2020 https://www.msdmanuals.com/professional/infectious-diseases/intestinal-protozoa-and-microsporidia/overview-of-intestinal-protozoan-and-microsporidia-infections