Tropical Enteropathy

Tropical enteropathy (environmental enteric dysfunction, EED) is a subclinical, chronic small intestinal disorder of villous blunting, increased permeability and inflammation, found in people living in settings with poor sanitation.

• Affects up to 40 to 90% of children in low income regions of Africa, South Asia and Latin America.
• Causes: repeated enteric infection and faecal contamination of the environment, malnutrition, micronutrient deficiency (zinc), aflatoxin, altered microbiome.
• Pathophysiology: villous atrophy, crypt hyperplasia, intraepithelial lymphocytes, reduced absorptive surface, chronic systemic inflammation and microbial translocation.
• Consequences: stunting, wasting, impaired oral vaccine response (rotavirus, polio, cholera), cognitive impairment, anaemia, recurrent diarrhoea, and failure of nutritional therapy.
• Distinct from tropical sprue, which is a clinical malabsorption syndrome with megaloblastic anaemia.

• Often asymptomatic or minimal gastrointestinal symptoms.
• Faltering growth in the first 2 years, stunting (height for age Z score below minus 2), poor weight gain despite adequate feeding.
• Recurrent diarrhoea, abdominal distension, poor appetite, irritability.
• Micronutrient deficiency signs (anaemia, zinc deficiency dermatitis, vitamin A deficiency).
• Poor response to nutritional rehabilitation.

• Clinical context and anthropometry (WHO growth standards).
• Biomarkers (research): lactulose to mannitol urinary ratio (increased permeability), faecal neopterin, myeloperoxidase, alpha 1 antitrypsin, calprotectin; serum markers of microbial translocation (LPS, sCD14), anti-flagellin antibodies, CRP, alpha 1 acid glycoprotein.
• Small bowel biopsy (rarely done): villous blunting, lymphocytic infiltrates.
• Exclude other causes: celiac disease, giardiasis, cryptosporidiosis, HIV enteropathy, tropical sprue, cystic fibrosis, cow's milk allergy, tuberculosis.
• Stool microscopy and PCR for parasites and pathogens; full blood count, ferritin, zinc, vitamin A.

• Prevention is central: water, sanitation and hygiene (WASH) interventions, handwashing, safe water, separation from animal faeces, exclusive breastfeeding for 6 months.
• Treat enteric infections promptly: oral rehydration solution (low osmolarity), zinc 20 mg daily for 10 to 14 days in children with diarrhoea (10 mg under 6 months).
• Nutritional rehabilitation: ready to use therapeutic foods for severe acute malnutrition, supplementary foods, animal source protein, micronutrients (vitamin A 100,000 to 200,000 IU every 6 months, iron, folic acid, zinc).
• Antibiotics for severe acute malnutrition: amoxicillin 40 mg/kg twice daily for 5 days. Routine azithromycin has limited effect on growth.
• Deworming (albendazole 400 mg single dose every 6 months) in endemic areas.
• Experimental therapies: mesalazine, nitazoxanide, rifaximin, glutamine, probiotics, and lipid based nutrient supplements have limited or inconsistent benefit.
• Vaccination (rotavirus, measles, oral cholera) and booster strategies.
• Follow up growth and developmental milestones.