Colorectal schistosomiasis: Is it still endemic in delta Egypt, early in the third millennium?

Abstract

Background:

Several governmental efforts have been exerted toward controlling schistosomiasis during the last decades in Egypt. This work was designed to study the prevalence of colorectal schistosomiasis in patients with different gastrointestinal symptoms.

Materials and Methods:

Patients presented to the gastroenterology unit with different gastrointestinal symptoms were endoscopically examined, where three to six tiny biopsies were taken from those with visible, suspected schistosomal lesions for histopathological examination and two additional rectal biopsies were taken from the apparently normal colonic mucosa. Form each patient, at least three stool samples were examined by the formal-ether concentration method for schistosoma ova.

Results:

Colonic abnormalities were detected in 510 out of 984 patients presented with different gut symptoms. Schistosoma mansoni was detected in 205 patients (180 males, 25 females) with an age range (18-65years). Six patients only had schistosomal polyps and excised successfully by snare polypectomy. The squash technique established the diagnosis of schistosomiasis in all endoscopically normal 118 (50.75%) cases by demonstrating the schistosomiasis ova and their associated histopathological findings showed no or minimal reaction in 96 (46.82%) cases and variable degrees of submucosal granulomata in the remaining cases. Stool examination detected the schistosomiasis ova in 25 (9.83%) patients only of the biopsy-positive cases.

Conclusions:

Our data revealed that despite governmental efforts, the prevalence of colorectal schistosomiasis (20.83%) is significant among patients with gut symptoms. Gaps in health care services should be detected and filled appropriately.

INTRODUCTION

Schistosomiasis has been a major public health problem in Egypt for thousands of years as it affects child development and adult productivity.[1] Schistosoma mansoni, prevalent in lower Egypt, causes intestinal schistosomiasis with frequent ova passage in stool which, later, becomes infrequent and scanty with subsequent disease progression due to submucosal fibrosis.[2,3] Controlling schistosomiasis morbidity has been achieved through improved health education, mass antischistosomal chemotherapy, and snail control within the activities of the primary health care system.[4] We aimed to study the prevalence of colorectal schistosomiasis in Egyptian patients with different gastrointestinal symptoms in the era of mass antischistosomal chemotherapy.

MATERIALS AND METHODS

Between January 2004 and March 2009, patients with different gastrointestinal symptoms, attending the gastroenterology unit of Mansoura Specialized Medical Hospital, were enrolled in this study. A total of three to six colonic biopsies (0.3-0.5 cm) were taken from each patient with a visible lesion during endoscopic examination, for histopathological examination by paraffin section. Two additional rectal biopsies were taken for crush biopsy (squash technique)[5] in patients even with apparently normal colonic mucosa. In suspected cases of schistosomiasis, at least three stool specimens were examined for ova by the formal-ether concentration method.[6] All patients received antischistosomal drugs, and followed up clinically 3-6 months later.

RESULTS

Endoscopic biopsies were taken for histopathological examination of 984 patients. Colonic mucosal abnormalities were reported in 510 patients only while the remaining 474 patients had normal colonic mucosa. S. mansoni was detected in 205 patients (180 males, 25 females) with an age range of18--65years (mean 39.2). Six (2.92%) patients only had sessile schistosomal polyps at the sigmoid colon. Detailed histopathological findings are shown in Table 1 and their endoscopic features are exhibited in Table 2.

Table 1.

Histopathological findings in patients with colorectal schistosomiasis

Table 2.

Endoscopic findings in patients with colorectal schistosomiasis

The squash technique established the diagnosis of schistosomiasis in all endoscopically normal 118(50.75%) cases by demonstrating the schistosomiasis ova with its characteristic lateral spine. Histopathological findings showed no or minimal reaction in 96 (46.82%) cases of them and variable degrees of submucosal granulomata in the remaining cases [Table 1].

Stool examination was positive for ova in 25 (9.83%) patients only out of 205 biopsy-positive schistosomiasis cases.

Table 3 showed that 31 (15.21%) patients had adenomatous polyps, and 5 (2.39%) patients had juvenile polyps and adenocarcinoma of the colon and rectum (in 19, 13 patients; respectively) from none of them schistosoma ova were retrieved.

Table 3.

Colonic biopsy findings

Patient symptoms with colorectal schistosomiasis are common and non specific as shown in Table 4 and their indications prior to endoscopic evaluation are exhibited in Table 5. After treatment with 40 mg/kg oral single dose of praziquantel, marked improvement of the intestinal symptoms was noted in most cases. Only 30 (14.34%) patients with advanced hepatosplenic schistosomiasis, reported slight improvement regarding gut symptoms. Only 15 (7.14%) patients performed follow up sigmoidoscopy after praziquantel therapy, in all of them normalization of the colonic mucosa was noted and biopsies were negative for schistosomiasis ova.

Table 4.

Symptoms in patients with schistosomiasis

Table 5.

Clinical impressions/indications for endoscopic evaluation

DISCUSSION

In the era of mass antischistosomal chemotherapy and improved health care facilities, the number of cases with schistosomiasis would be expected to decline. There are few recent studies on the schistosomal colonoscopic and histopathologic characteristics reflecting the progress in improvement in health care services.

In this work, symptoms of intestinal schistosomiasis were non-specific and resemble many gastrointestinal problems [Table 4]. Therefore, in endemic areas and village foci, schistosomiasis should be included in the differential diagnosis of all gastrointestinal complaints. Fortunately, early colorectal schistosomiasis is reversible and treatable by the specific schistosomicidal agents as praziquantel that proved to be effective in eradicating acute intestinal schistosomiasis and halting further disease progression.[1]

Finding the characteristic ova in stool samples establishes the diagnosis of acute intestinal schistosomiasis. But with chronicity, ova detection due to intermittent, infrequent ova passage and submucosal fibrosis[3] poses a difficulty in diagnosing chronic intestinal and hepatosplenic schistosomiasis.

Our study showed that stool examination was positive for schistosomal ova in only 9.83% of cases and a colonic or rectal biopsy may be positive while stool examination is negative for these ova; a data nullifying the role of stool examination alone in the diagnosis of intestinal schistosomiasis. The squash technique proved to be simple and effective in the demonstrating the characteristic ova of schistosomiasis in addition to the histological documentation of schistosomal granulomata even with endoscopically normal colorectal mucosa.

Endoscopy is not only a valuable tool in the diagnosis of colorectal schistosomiasis in its various stages but also in treatment of schistosomal polyps. In this study, all schistosomal polyps in six cases (2.92%) were excised effectively and completely without post endoscopy complications by snare polypectomy.

Colorectal malignancy was the clinical impression before referral for endoscopic evaluation in five (2.39%) patients; this adds an extra value for the diagnostic significance of endoscopy. If these cases were not endoscopically visualized and histopathologically examined, it would not be properly managed. Out of all studied cases, 32 (15.55%) patients had colonic or rectal cancers and they were all schistosomiasis free. This notion probably excluding the link between schistosomiasis and colorectal cancers. Otherwise, a significant association would be expected in areas endemic for schistosomiasis as in Nile delta, Egypt.

Schistosomal colonic disease is major health problem in endemic areas and if not diagnosed and treated early, might lead to complications such as chronic intestinal schistosomiasis and hepatosplenic schistosomiasis with high morbidity and mortality.[7]

CONCLUSIONS

Our data revealed that despite governmental efforts, the prevalence of colorectal schistosomiasis (20.83%) is significant among patients with gut symptoms. In endemic areas, schistosomiasis is still a considerable diagnostic possibility, put in mind of the gastroenterologists, even in the era of mass antischistosomal chemotherapy.