Tropical sprue is a malabsorption disease commonly found in tropical regions, marked with abnormal flattening of the villi and inflammation of the lining of the small intestine.
Signs and symptoms
The illness usually starts with an attack of acute
diarrhoea,
fever and
malaise following which, after a variable period, the patient settles into the chronic phase of diarrhoea,
steatorrhoea,
weight loss, anorexia, malaise, and nutritional deficiencies.
The symptoms of tropical sprue are:
Left untreated, nutrient and vitamin deficiencies may develop in patients with tropical sprue.
Cause
The cause of tropical sprue is not known.
It may be caused by persistent bacterial, viral, amoebal, or parasitic infections.
Folic acid deficiency, effects of malabsorbed fat on intestinal motility, and persistent small intestinal bacterial overgrowth may combine to cause the disorder.
A link between small intestinal bacterial overgrowth and tropical sprue has been proposed to be involved in the etiology of post-infectious irritable bowel syndrome (IBS).
Intestinal immunologic dysfunction, including deficiencies in secretory immunoglobulin A (IgA), may predispose people to malabsorption and bacterial colonization, so tropical sprue may be triggered in susceptible individuals following an acute enteric infection.
Diagnosis
Diagnosis of tropical sprue can be complicated because many diseases have similar symptoms. The following investigation results are suggestive:
Tropical sprue is largely limited to within about 30 degrees north and south of the equator. Recent travel to this region is a key factor in diagnosing this disease in residents of countries outside of that geographical region.
Other conditions which can resemble tropical sprue need to be differentiated.
Prevention
Preventive measures for visitors to tropical areas where the condition exists include steps to reduce the likelihood of
gastroenteritis. These may comprise using only
bottled water for drinking, brushing teeth, and washing food, and avoiding fruits washed with tap water (or consuming only peeled fruits, such as
bananas and oranges). Basic sanitation is necessary to reduce fecal-oral contamination and the impact of environmental enteropathy in the developing world.
Treatment
Once diagnosed, tropical sprue can be treated by a course of the antibiotic
tetracycline or
co-trimoxazole for 3 to 6 months.
Supplementation of vitamins B
12 and folic acid improves appetite and leads to a gain in weight.
Prognosis
The prognosis for tropical sprue may be excellent after treatment. It usually does not recur in people who get it during travel to affected regions. The recurrence rate for natives is about 20%,
but another study showed changes can persist for several years.
Epidemiology
Tropical sprue is common in the
Caribbean, Central and
South America, and
India and southeast
Asia. In the Caribbean, it appeared to be more common in Puerto Rico and Haiti. Epidemics in southern India have occurred.
History
The disease was first described by William Hillary
in 1759 in
Barbados.
Tropical sprue was responsible for one-sixth of all casualties sustained by the Allied forces in India and Southeast Asia during World War II.
The use of folic acid and vitamin B
12 in the treatment of tropical sprue was promoted in the late 1940s by Dr.
Tom Spies of the University of Alabama, while conducting his research in Cuba and Puerto Rico.
