Amebiasis presenting as acute appendicitis: Report of a case and review of Japanese literature

•The overall mortality rate reported in the studies in Japan (25%) is considerably higher than that reported in a systematic review conducted of similar studies in other countries (3.3%).•Japan is a low-risk area for amebiasis, and many physicians fail to consider amebiasis in the differential diagnosis of acute appendicitis. In all of the cases, the diagnosis occurred only after surgery.•It is important to conduct further examinations, including those for amebiasis, when appendectomy does not resolve acute appendicitis.

INTRODUCTIONOutside of these high-risk regions, acute amebic appendicitis is considerably rarer and the mortality rate is much higher than with non-amebic appendicitis.PRESENTATION OF CASEA 31-year-old woman presented with fever and right lower abdominal pain with no history of traveling abroad or sexual infection. Computed tomography revealed a dilated appendix and thickened cecal and ascending colon walls. She underwent an appendectomy for appendicitis. Owing to a lack of symptom resolution, we performed a pathologic examination of the appendix again that revealed multiple Entamoeba histolytica trophozoites; the serum amebic antibody was positive. She was treated postoperatively with metronidazole for amebiasis and discharged on postoperative day 12.DISCUSSIONThe mortality rate and frequency of severe postoperative intraabdominal complications were higher in the Japanese literature (1995–2013) (25% and 33%, respectively) than in other developed countries (3.3% and 19.4%, respectively). Japan is a low-risk area for amebiasis; many physicians fail to consider amebiasis in the differential diagnosis of acute abdomen. It is important to conduct further examinations, including those for amebiasis, when appendectomy does not resolve acute appendicitis.CONCLUSIONWe report a case of acute amebic appendicitis in a 31-year-old woman and review the ages at presentation, causative factors, treatments, and outcomes of 11 cases reported in Japan between 1995 and 2013.