Morbidity and Mortality Due to Schistosoma mansoni Related Periportal Fibrosis: Could Early Diagnosis of Varices Improve the Outcome Following Available Treatment Modalities in Sub Saharan Africa? A Scoping Review.

Daniel W Gunda,Humphrey D Mazigo,Paulina M Manyiri,Semvua B Kilonzo,Robert N Peck

doi:10.3390/tropicalmed5010020

Daniel W Gunda, Humphrey D Mazigo + Show 3 more

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https://doi.org/10.3390/tropicalmed5010020

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Abstract

Schistosomiasis affects about 240 million people worldwide and Schistosoma mansoni alone affects over 54 million people leaving 400 million at-risk especially in Sub Saharan Africa (SSA). About 20 million people are currently suffering from complications of chronic S. mansoni infection and up to 42% of those infected have been found with periportal fibrosis (PPF). About 0.2 million deaths are attributed to chronic S. mansoni every year, which is mainly due to varices. Death occurs in up to 29% of those who present late with bleeding varices even with the best available in-hospital care. The diagnosis of varices before incident bleeding could potentially improve the outcome of this subgroup of patients is SSA. However, there is no prior review which has ever evaluated this issue detailing the magnitude and outcome of varices following available treatment modalities among patients with Schistosoma PPF in SSA. This review summarizes the available literature on this matter and exposes potential practical gaps that could be bridged to maximize the long-term outcome of patients with S. mansoni related PPF in SSA. A total of 22 studies were included in this review. The average prevalence of varices was 82.1% (SD: 29.6; range: 11.1%–100%) among patients with PPF. Late diagnosis of varices was frequent with average bleeding and mortality of 71.2% (SD: 36.5; range: 4.3%–100.0%) and 13.6% (SD: 9.9; range: 3.5%–29%), respectively. Predictors were reported in seven (31.8%) studies including platelet count to splenic diameter ratio (PSDR) for prediction large varices in one study. Active S. mansoni infection was very prevalent, (mean: 69.9%; SD: 24.4; range: 29.2–100.0%). Praziquantel could reverse PPF and use of non-selective B-blockers reduced both rebleeding and mortality. Use of sclerotherapy for secondary prevention of variceal bleeding was associated with high rebleeding and mortality rates. Conclusions: This review shows that varices due to schistosomal PPF are a big problem in SSA. However, patients are often diagnosed late with fatal bleeding varices. No study had reported a clinical tool that could be useful in early diagnosis of patients with varices and no study reported on primary and effective secondary prevention of bleeding and its outcome. Regular screening for S. mansoni and the provision of Praziquantel (PZQ) is suggested in this review. More studies are required to bridge these practical gaps in Sub Saharan Africa.

Highlights

Schistosomiasis is a neglected tropical disease (NTD) that causes high morbidity and mortality mostly in African countries
This review is based on a systematic search of Pub Med, Google Scholar, and Web of science and citation lists of relevant publications according to the PRISMA checklist [16].To obtain the relevant kinds of literature from these electronic databases the following keywords were used: esophageal varices or esophagogastric varices and Schistosoma or Schistosoma mansoni or schistosomal periportal fibrosis and Sub Saharan Africa or Africa or “specific country names”
Six (27.3%), of the studies, included participants with periportal fibrosis who subsequently underwent endoscopic screening for esophageal varices and eight(36.4%) studies included participants with esophageal varices who subsequently underwent abdominal ultrasound scanning for the cause of portal hypertension

Summary

Introduction

Schistosomiasis is a neglected tropical disease (NTD) that causes high morbidity and mortality mostly in African countries. Sub Saharan Africa is the most affected part of the world where over 90% of the global burden of schistosomiasis is concentrated leading to an estimated 0.2 million loss of lives annually mainly due to chronic S. mansoni infection [1,3]. In Tanzania, for instance, high transmission of more 50% still occurs among communities that are engaged in fresh water-related activities [1,2] with school-aged children, women, and fishermen being at the highest risk of infection. Use of Praziquantel (PZQ) in mass drug administration (MDA) is common in most SSA countries mainly targeting the school-aged children there is a rapid and high re-infection rates post PZQ preventive treatment [5,6,7]. Occupational activities, poor sanitation, and lack of access to safe water significantly compromise the mitigation of S. mansoni transmission and most people are recurrently infected

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