What is Tropical Sprue?
Tropical sprue is a rare digestive and malabsorption disease which, as the name itself suggests, is commonly found in the tropical and sub-tropical regions. Tropical sprue is characterized by inflammation in the lining of the small intestine and abnormal flattening of the villi of the small intestine. There is a significant difference between tropical sprue and celiac sprue, as tropical sprue is a more severe type of environmental enteropathy. Patients suffering from tropical sprue are not able to absorb nutrients properly, especially folic acid and vitamin B12. The ability of the small intestine to absorb these nutrients becomes impaired leading to symptoms such as diarrhea, steatorrhea and anemia in the patient.
Small intestine normally has villi present in them, which are fingerlike projections that help in increased absorption of the nutrients by providing increased surface area in the intestine. In patients suffering from tropical sprue, there is flattening of these villi, which makes absorption of the nutrients difficult (malabsorption).
Causes of Tropical Sprue
The exact cause of tropical sprue is not clear. It is thought to occur due to persistent bacterial, viral, parasitic, amoeba infections. Persistent bacterial overgrowth in the small intestine can also contribute to this disorder.
Signs & Symptoms of Tropical Sprue
The initial symptoms of Tropical Sprue comprise of acute diarrhea, malaise and fever and after sometime, patient will have a chronic stage of diarrhea, steatorrhea, anorexia, weight loss, malaise with nutritional deficiencies. The common symptoms of tropical sprue include:
- Fatty stool or steatorrhea where the stool can be frothy, whitish in color and foul-smelling.
- Weight loss.
If tropical sprue is not treated, then the patient can develop vitamin and nutrient deficiencies with the following symptoms:
- Skin scales or hyperkeratosis in vitamin A deficiency.
- Anemia in vitamin B12 and folic acid deficiency.
- Bone pain, spasm, numbness and tingling sensation in vitamin D and calcium deficiency.
- Bruises in vitamin K deficiency.
Epidemiology of Tropical Sprue
Tropical sprue is commonly found in the Central and South America, Caribbean, India and southeast Asia. In the Caribbean region, it more often is seen in Haiti and Puerto Rico. There also have been reports of epidemics in southern India also.
Diagnosis of Tropical Sprue
It is difficult to diagnose tropical sprue, as there are many diseases and medical conditions with similar symptoms. If the patient has the following results from tests, then it indicates tropical sprue:
- Biopsy of tissue from small intestine shows presence of inflammatory cells (mostly lymphocytes).
- During an endoscopic procedure, inflammation of the lining of the small intestine and abnormal flattening of the villi is seen.
- Blood tests are done, which shows that the patient has decreased levels of vitamins A, B12, E, D, and K and also decreased levels of serum calcium, albumin and folate.
- There is thickening of the bowel folds seen upon imaging tests.
- Steatorrhoea is seen, which is the presence of excess fat in the feces.
Tropical sprue is mostly found and is restricted to an area within 30 degrees north and south of the equator. If a patient has recently traveled to this region, then it becomes a key factor in diagnosing tropical sprue. There are other medical conditions, which are similar to tropical sprue, such as celiac sprue/celiac disease/gluten sensitive enteropathy which produce symptoms that are similar to tropical sprue and include small intestine inflammation and flattening of the villi. The cause of celiac sprue is an autoimmune disorder in patients who are genetically susceptible and is triggered after consumption of gluten. Other conditions, which can cause malabsorption include tuberculosis, protozoan infections, HIV/AIDS, chronic pancreatitis and inflammatory bowel disease. Environmental enteropathy is another condition, which is similar to tropical sprue although it is less severe and is subclinical in nature.
Treatment for Tropical Sprue
After the diagnosis of tropical sprue has been made, treatment for it comprises of a course of antibiotics, such as sulfamethoxazole/trimethoprim or tetracycline, for around 3 to 6 months. Patient is also given vitamins B12 and folic acid supplements to improve appetite and weight gain.
Prevention of Tropical Sprue
The most important step for preventing tropical sprue is avoiding traveling to tropical regions. However, preventive measures can also be taken if you are visiting those regions or tropical areas where tropical sprue is prevalent and these measures include: drinking only bottled water, washing food, brushing teeth, eating only peeled fruits, such as oranges and bananas and following basic sanitation to reduce fecal to oral contamination.
Prognosis for Tropical Sprue
The prognosis for tropical sprue is very good if treatment is done. People who have acquired tropical sprue after travelling to affected regions usually do not experience a recurrence of this condition. The recurrence rate, however, in natives of tropical regions is about 20%.