Tropical Enteropathies

Abstract

Purpose of ReviewThe term ‘tropical enteropathy’ originated in observations in the 1960s that small intestinal morphology and function differed in the tropics from the norms found in temperate climates. It was subsequently shown that this enteropathy is more closely related to environmental conditions than latitude, and it was re-labelled ‘environmental enteropathy’. It is now recognised that environmental enteropathy (also now called environmental enteric dysfunction) has implications for the health and linear growth of children in low- and middle-income countries, and it may underlie poor responses to oral vaccination in these countries. The purpose of this review is to define and clarify this enteropathy despite the confusing terminology it has attracted and to contrast it with other enteropathic states.Recent FindingsRecent work has begun to demonstrate the nature of the mucosal lesion and the relationship with microbial translocation which is currently thought to link a failure of mucosal barrier function and the cascade of systemic inflammation which inhibits growth. The evidence is still correlative rather than definitive, but derives some additional support from animal models. There are some common features between environmental enteropathy and other enteropathies, but there are important differences also. The mechanism of the link between enteropathy and vaccine failure is not understood, and neither is it clear how the more severe form of enteropathy, which we refer to as malnutrition enteropathy, is driven by nutrient depletion and intestinal infection.SummaryTropical enteropathies form a group of disorders which include environmental and nutritional enteropathies. The long-term health implications of these disorders for health in low-income countries are just being explored, but the scale of their effects is very large, with millions of people affected.

A novel histological index for evaluation of environmental enteric dysfunction identifies geographic-specific features of enteropathy among children with suboptimal growth

“…This includes histologic features that have been identified among individuals from indigenous populations and from travelers spending time in "tropical" areas that have experienced chronic malabsorption syndromes, so-called "tropical sprue" [53]. Similar histologic changes have been noted in asymptomatic individuals in the same geographic areas, so-called" "tropical enteropathy", now referred to as environmental enteropathy or as EED [10,54]. Among the issues that have hampered identification and subclassification of EED and the discovery of its underlying etiologies has been the lack of a robust and systematic method of categorizing and quantifying the intestinal histologic changes from cohorts of affected individuals.…”

Post-infection irritable bowel syndrome or tropical sprue: A paradigm shift

“…Recently, an entity quite similar to tropical enteropathy has been reported among children from multiple countries with a different name, environmental enteric dysfunction 21 . This is characterized by stunted growth, mucosal abnormalities in the small bowel including abnormal permeability and gut dysbiosis 21 .…”

“…Recently, an entity quite similar to tropical enteropathy has been reported among children from multiple countries with a different name, environmental enteric dysfunction 21 . This is characterized by stunted growth, mucosal abnormalities in the small bowel including abnormal permeability and gut dysbiosis 21 . 22 , abnormal luminal metabolome, increased small intestinal permeability, abnormal small intestinal mucosal histology, mucosal immune activation in response to pathogenic infection by bacterial, protozoa and virus, and neurohormonal dysregulation 1,6 .…”

Thiamine content of F‐75 therapeutic milk for complicated severe acute malnutrition: time for a change?

“…Reduced intestinal absorptive capacity during environmental enteropathy and malnutrition may also lead to thiamine insufficiency (subclinical low vitamin B 1 levels) . Gut microbiota is also affected in malnourished children, which might affect thiamine‐uptake capacity …”

“…21 Gut microbiota is also affected in malnourished children, which might affect thiamine-uptake capacity. [22][23][24] A relative inadequacy of thiamine content to caloric ratio, such as is found in individuals on highcarbohydrate diets, is also a common precipitating factor of thiamine insufficiency (e.g., pure cassava or milled rice). 25 This very same imbalance can contribute to the onset of thiamine deficiency when dextrose-based fluids are administered without thiamine supplementation in critically ill patients.…”