What Hides Behind Bloody Diarrhea?

Abstract

Question: A 65-year-old Caucasian man had an unremarkable medical history with no sexual risk behavior or current medication. The patient came to our Emergency Department with a 2-month history of bloody diarrhea with mucus (5 bowel movements per day) and rectal tenesmus. He denied fever, anorexia, abdominal pain or weight loss. Physical examination showed a mild abdominal discomfort in the left lower quadrant without tenderness. Laboratory analysis revealed a mild leukocytosis (11.7;N:4-10*109/L) and C-reactive protein of 0.65 (N<0.5mg/dL). Plain abdominal X-ray showed no dilation or air-free levels of bowel loops. We decided to perform a colonoscopy after a retrograde bowel preparation and it was possible to reach cecum with a reasonable bowel preparation (Boston bowel preparation scale 2/2/3), that showed multiple pseudopolyps with oval to linear apical ulcers with 3-12mm in diameter and congestive and erythematous surrounding mucosa along the sigmoid colon and rectum (Figures A-C). What is the diagnosis?A.Ulcerative proctosigmoiditisB.Ischemic proctosigmoiditisC.Amebic proctosigmoiditisD.Cytomegalovirus proctosigmoiditis Look on page 2044 for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image(s) to Practical Teaching Cases. The correct answer is C. The multiple ulcers found in the sigmoid colon and rectum were deep and flask-shaped (Figures A-C). When specifically questioned, the patient mentioned that he lived for few years in Cape Verde and has been living in Portugal for 3 months. Stool studies were positive for Entamoeba histolytica trophozoites and antigen. Amebic serology was also positive. Histopathology of the biopsy specimens revealed focal proctosigmoiditis with neutrophilic cryptitis, lymphoplasmocytic infiltrate, and numerous hemophagocytic amebic trophozoites (Figure D; H&E, 100×). The patient was successfully treated with 2-week course of metronidazole 500mg orally tid followed by 7 days of paromomycin 250mg orally tid with no recurrence during 6-month follow-up. Invasive amebiasis caused by Entamoeba histolytica trophozoites is an uncommon cause of bloody diarrhea. In developed countries, amebiasis is most often seen in recent immigrants from endemic areas (Central and South America, Africa and India). Most patients are asymptomatically colonized by parasites and rarely develop disease in the absence of immunocompromised conditions.1Hechenbleikner E.M. McQuade J.A. Parasitic colitis.Clin Colon Rectal Surg. 2015; 28: 79-86Crossref Scopus (21) Google Scholar, 2Lee K.C. Lu C.C. Hu W.H. et al.Colonoscopic diagnosis of amebiasis: a case series and systematic review.Int J Colorectal Dis. 2015; 30: 31-41Crossref PubMed Scopus (20) Google Scholar Gastrointestinal symptoms are nonspecific and can mimic other colonic diseases. Complicated forms such as bleeding, peritonitis or obstruction can occur.1Hechenbleikner E.M. McQuade J.A. Parasitic colitis.Clin Colon Rectal Surg. 2015; 28: 79-86Crossref Scopus (21) Google Scholar, 3Singh R. Balekuduru A. Simon E.G. et al.The differentiation of amebic colitis from inflammatory bowel disease on endoscopic mucosal biopsies.Indian J Pathol Microbiol. 2015; 58: 427-432Crossref PubMed Scopus (17) Google Scholar Endoscopic appearance can also mimic inflammatory, ischemic or infectious conditions, being histology crucial for the differential diagnosis.3Singh R. Balekuduru A. Simon E.G. et al.The differentiation of amebic colitis from inflammatory bowel disease on endoscopic mucosal biopsies.Indian J Pathol Microbiol. 2015; 58: 427-432Crossref PubMed Scopus (17) Google Scholar In amebic colitis, biopsies should be directed to the necrotic base of the ulcers to increase the diagnostic accuracy.2Lee K.C. Lu C.C. Hu W.H. et al.Colonoscopic diagnosis of amebiasis: a case series and systematic review.Int J Colorectal Dis. 2015; 30: 31-41Crossref PubMed Scopus (20) Google Scholar Inflammatory bowel disease is one of the important differential diagnosis with a similar endoscopic appearance, but a completely distinct management.2Lee K.C. Lu C.C. Hu W.H. et al.Colonoscopic diagnosis of amebiasis: a case series and systematic review.Int J Colorectal Dis. 2015; 30: 31-41Crossref PubMed Scopus (20) Google Scholar In addition, mistreatment with steroids can lead to complicated and potentially life-threatening forms of amebiases.1Hechenbleikner E.M. McQuade J.A. Parasitic colitis.Clin Colon Rectal Surg. 2015; 28: 79-86Crossref Scopus (21) Google Scholar, 2Lee K.C. Lu C.C. Hu W.H. et al.Colonoscopic diagnosis of amebiasis: a case series and systematic review.Int J Colorectal Dis. 2015; 30: 31-41Crossref PubMed Scopus (20) Google Scholar Treatment includes metronidazole or tinidazole followed by a luminal agent to eradicate intraluminal encysted E histolytica.1Hechenbleikner E.M. McQuade J.A. Parasitic colitis.Clin Colon Rectal Surg. 2015; 28: 79-86Crossref Scopus (21) Google Scholar This case highlights the need for a high level of suspicion and investigate an appropriate epidemiological context for the establishment of a prompt and effective antibiotic therapy, including a supplementary luminal amebicide. *Authors share co-first authorship. CME Exam 1: What Hides Behind Bloody Diarrhea?GastroenterologyVol. 154Issue 8Preview Full-Text PDF