eMedicine Specialties > Gastroenterology > Intestine
Author: Rohan C Clarke, MD, Consulting Staff, Department of Gastroenterology, JPS Health Systems Hospital
Coauthor(s): Rachael M Ferraro, DO, Consulting Staff, Department of Internal Medicine, Regency Hospital and Kindred Hospital; Lisa Ozick, MD, Former Chief, Divisionof Gastroenterology, Harlem Hospital Center; Sabo B Tanimu, MD, Fellow, Department of Medicine, Division of Gastroenterology, Harlem Hospital Center; Oluyinka S Adediji, MD, Consulting Staff, Department of Adult and General Medicine, Health Services Incorporated, Montgomery, Alabama
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Updated: Jan 3, 2010
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Tropical sprue (TS) is a syndrome characterized by acute orchronic diarrhea, weight loss, and malabsorption of nutrients. It occurs in residents of or visitors to the tropics and subtropics. The first description of tropical sprue is attributed to William Hillary's 1759 account of his observations of chronic diarrhea while in Barbados. Subsequently, tropical sprue was described in tropical climates throughout the world. The definition has been expanded toinclude malabsorption of at least 2 different substances when other causes are excluded.
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Endoscopic views of unsuspected celiac disease. A: Absent duodenal folds. B: Mucosal fissures and scalloped folds. C: Scalloped fold.
The exact causative factor of tropical sprue is unknown, but an intestinal microbial infection is believed to be the initiating insult. The infectionresults in enterocyte injury, intestinal stasis, and possible bacteria overgrowth. Villous destruction and demonstrable nutrient malabsorption occur in varying degrees. Folate, vitamin B-12, and iron deficiencies are the most common nutrient deficiencies.
The exact role of microbial agents in the initiation and propagation of the disease is poorly understood. One theory is that anacute intestinal infection leads to jejunal and ileal mucosa injury; then intestinal bacterial overgrowth and increased plasma enteroglucagon results in retardation of small-intestinal transit. Central to this process is folate deficiency, which probably contributes to further mucosal injury.
Hormone enteroglucagon and motilin levels are elevated in patients with tropical sprue. Enterocyte injurycan cause these elevations. Enteroglucagon causes intestinal stasis, but the role of motilin is not clear.
The upper small intestine is predominantly affected; however, because it is a progressive and contiguous disease, the distal small intestine up to the terminal ileum may be involved. Pathological changes are rarely demonstrated in the stomach and colon. Coliform bacteria, such asKlebsiella, E coli and Enterobacter species are isolated and are the usual organisms associated with tropical sprue.1,2,3,4
Tropical sprue occurs in geographically limited areas. The syndrome is not reported in US patients unless they have lived in or traveled to any of the areas described below.
Tropical sprue occurs in both epidemic and endemic forms, primarilyin Southeast Asia and the Caribbean. The actual prevalence of the endemic form is difficult to estimate, but rates as high as 8% are reported in Puerto Rico. One unusual feature is that tropical sprue appears to be limited to certain geographic areas, even within the tropics. For example, although tropical sprue is commonly reported in Puerto Rico and the Dominican Republic, it is not reported...