Background Amoebic colitis, caused by Entamoeba histolytica is an emerging diagnostic challenge for gastroenterologists in developed countries. Due to the similarity of symptoms and endoscopic findings, it can be easily misdiagnosed as inflammatory bowel disease (IBD) with a potentially devastating outcome especially if patient receives immunosuppression. The aim of this study is to look into the misdiagnosed cases to identify the challenges in differentiating amoebic colitis from IBD and to outline strategies to avoid this Methods Clinical and electronic case notes for the 4 patients, who were misdiagnosed as IBD between September 2015 to February 2019 at University Hospitals of Leicester U.K. were reviewed. The histology of resected colon specimens and endoscopic colonic biopsies were re-reviewed specifically for amoebic trophozoites. Results Three were male and 1 female. 1 patient was Caucasian while 3 patients were British Asian. Their mean age was 47.75 years (range 28–71). 3 cases were new IBD presentations while 1 patient was misdiagnosed as IBD since 2015. Two patients had a travel history to India and travelled to South East Asia 12 months prior to presentation. The travel history for 1 patient was not available. All 4 cases presented with bloody diarrhoea and had an endoscopic examination around the time of diagnosis which suggested acute inflammation likely IBD. Three were treated as ulcerative colitis while 1 patient was treated as Crohn’s disease. One patient required rescue therapy with cyclosporin while on intravenous steroids. As clinical symptoms worsened with rescue therapy, the patient required a subtotal colectomy. Similarly the patient who was treated for Crohn’s disease with Azathioprine and intravenous steroids, required subtotal colectomy due to recurrent flare ups. The other two cases were successfully treated with antimicrobial after the diagnosis of amoebic colitis although one of them received adalimumab prior to the correct diagnosis. The diagnosis of amoebic colitis was made through histological examination of the resected colon in 2 patients, colonic biopsy in 1 patient and stool E. histolytica DNA polymerase chain reaction (PCR) in 1 patient. Conclusion All 4 cases who were misdiagnosed as IBD had the diagnostic challenge of differentiating IBD from amoebic colitis due to similarity of symptoms and the endoscopic findings. Travel history is an important clue and should be considered for any patient presenting with colitis. New local guidelines were introduced to screen all patient with colitis for E. histolytica with serology and stool PCR. Patients requiring immunosuppression for suspected IBD are commenced on antimicrobial cover until E. histolytica results are available.

No abstract

Background Amoebic colitis can mimic inflammatory bowel disease (IBD) in clinical presentation, endoscopic and (to some extent) histological findings. Four patients with amoebic colitis were misdiagnosed with IBD or an IBD flare at University Hospitals of Leicester (UHL), UK in 2018. This prompted a change in practise in our department and we began screening for Entamoeba histolytica in patients with newly-diagnosed IBD, a flare or those being considered for biologics. We analysed cases of possible amoebic colitis after this change by reviewing IBD patients with a positive E. histolytica immunofluorescence antibody test (IFAT). Methods We conducted a retrospective electronic and case note review of patients with IBD and positive amoeba IFAT serology >1:80 from April 2019 through September 2019. We collected information including Crohn’s disease (CD), ulcerative colitis (UC), IBD treatment, histological findings, travel history, stool E. histolytica DNA polymerase chain reaction (PCR) and amoebic serology including IFAT and Cellulose Acetate Precipitin test (CAP). The histology of endoscopic biopsies for 16 of the IFAT positive patients was reviewed specifically for amoebic trophozoites. Results During the study period we identified 26 IFAT positive patients, excluded 3 patients that were felt to be non-IBD; 23 were included in the study. The median age was 37.8 (range 16–86); 43.5% were male. Four had a diagnosis of UC; 19 had CD. 12 were new IBD presentations. Seven patients had a relevant travel history (Jamaica, Thailand, Turkey, Italy, Greece, and Spain). Four did not have a travel history. Travel history was unknown for 12. Three patients were on biologics, one on biologics and thiopurines. Five were on thiopurines, three on thiopurines and steroids. Four were on steroids only, four on 5-ASAs. Three were on no treatment. Two out of 16 patients reviewed had amoebic trophozoites on endoscopic biopsy, unfortunately stool PCR was not sent on these two patients. Stool E. histolytica DNA PCR, was sent for 19 patients and was negative in those cases. All 24 patients were negative for CAP. Conclusion While IFAT is helpful in detecting past exposure it is only 75% sensitive for amoebic colitis. Even if IFAT and CAP are combined it is difficult to differentiate amoebic colitis from IBD. It is not clear if these cases represent past infections, early infections that precipitated an IBD flare, early infections that arose in the setting of immunosuppression, or false positive IFATs. The risk of infection in the immunosuppressed patient is high and the consequences of misdiagnosis are significant therefore a comprehensive screening method is merited; this may encompass IFAT ± CAP, stool E. histolytica DNA PCR, and possibly histological review.