Idiopathic Tropical malabsorption syndrome | Medical Science Optional Notes for UPSC PDF Download

Introduction

• Also known as environmental enteropathy.
• Observed in various regions of sub-Saharan Africa, including Gambia, as well as among aboriginal populations in northern Australia, and specific communities in South America and Asia, such as impoverished areas in Brazil, Guatemala, India, and Pakistan.
• The causes and development mechanisms of tropical sprue remain unclear.
• While malnutrition is believed to play a role in the disorder, neither additional feeding nor the supplementation of vitamins and minerals can completely reverse the syndrome.

Role of Folic acid deficiency

• Folic acid absorption occurs primarily in the duodenum and proximal jejunum.
• Individuals with tropical sprue often exhibit signs of folate malabsorption and deficiency.
• Folate deficiency can lead to alterations in the small-intestinal mucosa, and these changes can be reversed through folate replacement.
• Some early studies suggested that tropical sprue could be treated with folic acid; however, these studies did not elucidate the initial cause or "insult" responsible for folate malabsorption in the first place.

Presentation

Recurrent episodes of diarrhea experienced during the initial 2 to 3 years of life create a cycle of mucosal damage, malnutrition, infection, and inflammation. This cycle adversely impacts both physical and cognitive growth and development.

Diagnosis

• Persistent diarrhea in tropical climates is frequently caused by infectious agents such as G. lamblia, Yersinia enterocolitica, C. difficile, Cryptosporidium parvum, and Cyclospora cayetanensis.
• Before considering tropical sprue as a potential diagnosis, it is essential to rule out the presence of cysts and trophozoites in three consecutive stool samples.
• Small-intestinal biopsies in tropical sprue lack distinctive features but often resemble those found in celiac disease, making them difficult to differentiate.
• In tropical sprue, biopsy samples show less alteration in villous architecture and more infiltration of mononuclear cells in the lamina propria compared to celiac disease.
• Unlike celiac disease, the histological characteristics of tropical sprue exhibit similar severity throughout the small intestine, and a gluten-free diet does not lead to clinical or histological improvement in tropical sprue.

Treatment

• Effective treatment for tropical sprue commonly involves broad-spectrum antibiotics and folic acid, particularly if the patient relocates from the tropical region and does not return.
• Tetracycline, administered for a duration of up to 6 months, may lead to noticeable improvement within 1-2 weeks.
• Folic acid alone can bring about hematologic remission, enhance appetite, promote weight gain, and induce certain morphologic changes in small-intestinal biopsy.
• Due to significant folate deficiency, folic acid is typically administered concurrently with antibiotics.