Environmental enteropathy

Clinic

• EE = Tropical enteropathy = Environmental enteric dysfunction
• It is a disorder of chronic intestinal inflammation.
• EE is most common amongst children living in low-resource settings. Acute symptoms are typically minimal or absent.
• EE can lead to malnutrition, anemia (iron-deficiency anemia and anemia of chronic inflammation), growth stunting, impaired brain development, and impaired response to oral vaccinations.

Signs and symptoms

Environmental enteropathy is believed to result in chronic malnutrition and subsequent growth stunting (low height-for-age measurement) as well as other child development deficits.

Long-term symptoms

• Malnutrition
  • EE causes malnutrition by way of both malabsorption and nutritional deficiencies.
• Growth and physical development
  • The first two years (and the prior 9 months of fetal life) are critical for linear growth. Stunting is an easy to measure symptom of these child development deficits.
• Neurocognitive (brain development)
• Effect on oral vaccination
  • Many oral vaccines, both live and non-living, have proven to be less immunogenic or less protective when administered to infants, children or adults living in low socioeconomic conditions in developing countries than they are when used in industrialized countries. Widespread EE is hypothesized to be a contributing cause for this observation.

Child receiving oral polio vaccine. There is some evidence that the enteric dysfunction characteristic of EE may impair the efficacy of oral vaccinations.

Causes

The development of EE is multifactorial, but predominantly associated with chronic exposure to contaminated food and water. This is especially true in environments where widespread open defecation and lack of sanitation are common.

Mechanism

Long-term exposure to environmental pathogens leads to a generalized state of intestinal inflammation. Chronic inflammation leads to both functional and structural changes which alter gut permeability and ability of the intestine to absorb nutrients. Evidence of villous atrophy in endoscopic images of the small intestine. Specifically, structural changes within the intestine include smaller villi, larger crypts (called crypt hyperplasia), increased permeability, and inflammatory cell build-up within the intestines. These changes result in poor absorption of food, vitamins and minerals – or "modest malabsorption".

Note

Neurocognition would be the effect of malabsorbtion but recently Recently, the idea has been raised that maybe the developmental deficits is not necessarily caused by nutrient mal absorption, but maybe both are caused by a common etiology.