Definition & Facts
People who live in or frequent regions of the world that lie 30 degrees south or north of the equator are most at risk for developing tropical sprue. Countries that are affected include those in the Caribbean, Africa, and Southeast Asia.
Symptoms & Complaints
- Diarrhea, especially when they eat foods high in fat
- Fatty, bad-smelling, clay-colored stool
- Cramps in the muscles and cramps in the abdomen
- Unexplained weight loss
- Night blindness, dry eyes and dry skin, loss of appetite, and loss of the sense of smell due to vitamin A deficiency.
- Anemia, soreness and weakness in the arms and legs due to vitamin B12 deficiency. Symptoms of B12 deficiency are rare, because the body has its own stores of the vitamin that can take several months to deplete.
- Tongue inflammation (glossitis), prematurely graying hair, gastrointestinal tract disturbances due to folic acid deficiency.
- Soft or painful bones due to deficiencies of calcium and vitamin D deficiency.
- Easy bruising due to vitamin K deficiency. People with this deficiency are more likely to suffer nosebleeds or miscarriages.
Tropical sprue is caused when the intestines become inflamed and swollen to the point where it is difficult for them to absorb vitamins, minerals and other nutrients.
When the inside of the small intestines are examined, pathologists notice that the villi are flattened. These are tiny projections that resemble fingers, and increase the surface area of the intestines. This makes them able to absorb many more nutrients than they would if the lining of the intestines were smooth. When villi are flattened, their ability to absorb nutrients is impaired.
There is no consensus among doctors as to what causes the intestinal inflammation of tropical sprue. Some believe that it is caused by too many of a certain bacteria in the gut, but they are not sure which types of bacteria those are. Others believe tropical sprue is caused by infections by viruses or microbes or that poorly absorbed fat or a deficiency in folic acid itself leads to tropical sprue.
Diagnosis & Tests
Because tropical sprue resembles many other disorders of the gastrointestinal tract, the doctor orders tests to rule other diseases out. They include giardiasis, ulcerative colitis, and other inflammatory bowel diseases. Celiac disease is another disease that has signs and symptoms very much like tropical sprue.
However, celiac disease is an autoimmune disorder, which means that the body attacks its own cells. If these other diseases are ruled out, and the person lives in or travels to tropical areas fairly often, the doctor gives a diagnosis of tropical sprue.
An enteroscopy is another diagnostic tool for tropical sprue. The doctor inserts a flexible tube with a tiny camera known as an endoscope inside the patient’s mouth and down to the small intestine. The endoscope not only allows the doctor to see inside the patient’s GI tract, but can remove a small bit of the intestinal tissue for analysis. The enteroscopy takes between 45 minutes to two hours and is an outpatient procedure. The patient may be sedated but needs to stay awake enough to follow the doctor’s instructions.
If the patient has tropical sprue, an examination of the biopsied tissue under the microscope shows the abnormal villi as well as characteristic swelling and inflammation. Lymphocytes, which are white blood cells sent to an injured area by the body and cause what’s usually healing inflammation, are also found.
Doctors have the patient’s stool examined. The stool of a tropical sprue patient has a large amount of fat (steatorrhea). Imaging tests show small intestines that are abnormally thickened. Since the disease causes nutritional deficiencies, the doctor may also test for them. These tests check the patient’s bone density, blood cell count, levels of folate, vitamin B12, and vitamin D.
Treatment & Therapy
The symptoms of tropical sprue can be readily eased by antibiotics like tetracycline, which has been used for decades. However, this drug is not given to children until their permanent teeth have grown in, since it can cause discoloration. The doctor may also prescribe other antibiotics such as trimethoprim or ampicillin.
A patient may need to take a course of antibiotics for as long as a year before their tropical sprue is defeated, though many patients experience relief after only a few weeks. The earlier the disease is treated, the faster the patient’s recovery.
The doctor must also treat a patient with tropical sprue for malabsorption. This means prescribing nutrients to compensate for the ones that are lacking due to the disease. They include vitamins, fluids, minerals such as iron and electrolytes, which are ions that help regulate various bodily functions. The patient will probably need to take folic acid for about three months or longer, and this vitamin may be enough to dramatically improve their symptoms. Patients may also be given vitamin B12 and medicines to control their diarrhea.
A patient who is not treated for tropical sprue in a timely manner may have recurrences, or have permanent damage in their small intestine that makes absorption of most nutrients difficult.
Prevention & Prophylaxis
Though some professionals believe there’s little a person who lives or regularly travels to a tropical area can do to avoid tropical sprue, others believe that proper hygiene lowers the risk. The person should only drink and cook with bottled water that they know is clean, and only eat fruits that have a thick peel or a husk. Other fruits should be washed with bottled, not tap water, and the visitor should avoid foods sold on the street.
However, tropical sprue is fairly easy to treat, and the prognosis is very good. People who only travel to the tropics usually don't suffer a recurrence of the disease, and recurrence is fairly low even among people who live in the tropics.