Tropical sprue is a syndrome of diarrhea, weight loss, malabsorption, and abnormal duodenal histopathology.

Most cases of tropical sprue occur in Asia (especially India), the Caribbean islands including Puerto Rico, and parts of Central and South America. The disease is seen in some but not all equatorial regions between the north and south 30° latitude.

Individuals indigenous to these regions can contract the illness, as can visitors to these regions, although the illness is not seen in visitors / tourists unless they remain in endemic regions for at least 2 weeks.

The pathogenesis of this condition is not well known. It is most common in adults. It is suspected that an infectious agent causes tropical sprue, although no specific pathogenic organism has been identified as the sole cause of this condition. Patients often have small bowel bacterial overgrowth, and the condition often resolves with antibiotic therapy.

Patients typically describe prolonged diarrhea that often started as an acute episode of diarrhea. They frequently have crampy abdominal pain and nausea. Malabsorption of nutrients may cause additional symptoms (including night blindness in patients with vitamin A deficiency).

Physical examination is rarely helpful in making the diagnosis unless physical signs of a nutritional deficiency can be identified. Laboratory studies may reveal a macrocytic anemia. Deficiencies of vitamin B12 or folate may be identified. Small bowel biopsy will reveal partial villus atrophy and will establish the diagnosis.