Nondysenteric intestinal amebiasis colonic morphology and search forEntamoeba histolytica adherence and invasion

Abstract

There is controversy regarding the presence of colonic mucosal abnormalities or mucosal invasion by Entamoeba histolytica in patients with "nondysenteric intestinal amebiasis." To determine the role of E. histolytica in causing symptoms and mucosal changes and to detect if mucosal invasion by E. histolytica is present in nondynsenteric intestinal amebiasis, we evaluated 24 E. histolytica-infected patients (stool microscopy positive for E. histolytica) and 12 noninfected controls who presented with chronic gastrointestinal symptoms, but without dysentery, to a clinic in Calcutta. The colonic mucosa was evaluated at colonoscopy, and mucosal biopsies obtained from the cecum, sigmoid colon, and rectum were evaluated by light microscopy, indirect immunofluorescence microscopy, and scanning electron microscopy. At colonoscopy mucosal ulcerations were absent in all the controls and all except one of the E. histolytica-infected patients. E. histolytica trophozoites or cysts were not seen in the lamina propria or on the luminal surface in any infected patient by light and immunofluorescence microscopy. On scanning electron microscopy, structures that resembled rounded E. histolytica trophozoites were seen on the luminal surface in two of 19 cecal specimens from the infected patients. Moderate or severe mucosal inflammation was frequent on light microscopy in both the E. histolytica-infected patients and the noninfected controls with the cecum involved in two thirds of both groups. Antibodies to E. histolytica were detected in serum of 25% of study patients and 58% of controls. Mucosal inflammation did not correlate with stool positivity for E. histolytica or seropositivity for ameba antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

Differentiation of entamoeba histolytica/entamoeba dispar by PCR and their correlation with humoral and cellular immunity in individuals with clinical variants of amoebiasis.

“…The etiology of CIA has not been settled and clear-cut differences between this disease and the syndrome of irritable bowel have not been defined. 69,70 Infection in all the cases where it could be determined in the cohort of CIA, (characterized by abdominal distension, colicky pain, tenesmus, alternating diarrhea and constipation, and positive serology) was due to E. dispar. Studies carried out in India, 71 Panama, 72 Puerto Rico, 73 and Honduras 74 have shown that the typical abdominal symptoms of CIA were observed more frequently in individuals negative for amoeba in feces.…”

Clinical evaluation and management of acute severe colitis

“…Other treatment modalities include "rolling," in which frequent shifting of the patient's position in bed is used to mobilize colonic gas and thus decrease dilatation (163,164), and decompression using a flexible tube passed into the colon during X-ray transillumination. In severe cases colectomy should be considered, as this may be life saving (165,167,168). Decompressive measures have been reported to be of value also in toxic megacolon due to other pathogens or idiopathic disease (131).…”

“…Amoebic colitis may be either mild and nonhemorrhagic (168) or more of a dysenteric illness with abdominal pain, tenesmus, and frequent mucopurulent bloody stools. It may run a protracted course clinically indistinguishable from chronic UC, and may also be relapsing.…”

Prevalence and Importance of Amebic Infestation in Patients with Ulcerative Colitis in Two Regions in Turkey

“…While the two conditions might be difficult to differentiate, physicians practising in endemic regions are familiar with this problem [16,34,36]. Endoscopic findings in amebic colitis may vary, and acute-phase findings are particularly difficult to differentiate from UC [10,11]. We were unable to establish a correlation between amebic infections and the colonic localization of UC; however, it is of interest that no UC cases with rectal localization had amebiasis.…”

“…Entamoeba histolytica is a common cause of infectious colitis and amebic abscess [9]. The clinical, symptomatic, and endoscopic differentiation of amebic colitis and inflammatory bowel disease is difficult [10][11][12][13]. The same difficulty exists in histopathological examination, increasing the likelihood of misdiagnosis.…”