Tropical sprue: what is it, causes, symptoms, treatment, prognosis

What is Tropical Sprue?

Tropical sprue (tropical diarrhea) Is a rare disease of the digestive system in which the ability of the small intestine to absorb nutrients is impaired (malabsorption). Hence, nutritional deficiencies and abnormalities of the mucous membrane of the small intestine may be present. The exact cause of sprue is unknown, but the disorder may be related to environmental and dietary conditions in tropical regions where it is most common.

Signs and symptoms

Tropical sprue symptoms may include fatigue and diarrhea with copious, pale and unpleasant stool odor. People with this disorder may also experience:

• deep loss of appetite (anorexia);
• pain in the tongue;
• night blindness;
• weight loss;
• loss of strength and energy (asthenia) and general weakness.

The onset of tropical sprue can be sudden. Patients may have:

• abnormally high temperature;
• inflammation of the mouth and tongue;
• dry skin;
• the appearance of scales on the lips and corners of the mouth.

Sometimes psychological depression.

In some people with tropical sprue, symptoms disappear as suddenly as they may have started (spontaneous remission). Early treatment of the disease can lead to a quick and complete recovery. The return to normal bowel structure and function may be slower if sprue treatment is started later in the course of the disease. In some cases, the disease can become chronic with frequent relapses.

Patients with this disorder may develop anemiacharacterized by the presence of abnormally enlarged blood cells (megaloblasts) in the bone marrow (megaloblastic anemia).

Causes and risk factors

The exact cause of the tropical sprue is unknown. It is an acquired disorder that may be related to environmental and nutritional factors, or sprue may be caused by an infectious an organism (viral or bacterial), food poisoning, parasitic infection, or nutritional deficiencies such as folic acid (vitamin B9). Tropical sprue causes damage to the intestinal mucosa, which leads to impaired absorption of food, minerals and water.

Affected populations

Tropical sprue occurs in both epidemic and endemic forms, mainly in Southeast Asia and the Caribbean. The actual prevalence of this endemic form is difficult to estimate, but in Puerto Rico it is as high as 8%. One unusual feature is that tropical sprue appears to be limited to certain geographic areas, even within the tropics. For example, although tropical sprue are commonly found in Puerto Rico and the Dominican Republic, they are not reported in Jamaica. Only a few cases have been reported in emigrants from southern Africa.

Symptomatic disorders

Symptoms of the following conditions may be similar to those of tropical sprue. Comparisons can be useful for differential diagnosis:

• Malabsorption syndromes belong to the group of digestive disorders, which are characterized by impaired absorption of nutrients and excessive loss of unabsorbed substances in the feces. Many major diseases are associated with these syndromes. Symptoms are directly related to the severity of the disorder. Diarrhea and a large volume of fatty stools are persistent symptoms in patients with malabsorption syndrome.
• Giardiasis (giardiasis) - a rare infection of the small intestine caused by a single-celled organism Giardia lamblia (intestinal lamblia). Like tropical sprue, this disease is characterized by impaired absorption of various nutrients by the small intestine. Symptoms may include abdominal cramps, abdominal pain, watery diarrhea, excessive gas, and foul stool odor. Later in the course of the illness, you may experience other symptoms such as weight loss and profound loss of appetite (anorexia).
• Crohn's disease represents inflammatory bowel diseasecharacterized by severe chronic inflammation of the intestinal wall or other part of the gastrointestinal tract. Symptoms that can develop over time include nausea, vomiting, fever, night sweats, a general feeling of weakness, and waves of abdominal pain and discomfort. Diarrhea is common and rectal bleeding. Crohn's disease can be difficult to recognize and treat. Diagnosis is often delayed.
• Ulcerative colitis - acute inflammatory bowel diseasecharacterized by diarrhea and blood in stool due to multiple irregular ulcerations of the intestines. Initial symptoms may include a general feeling of weakness (malaise) and fatigue. Abdominal discomfort may occur with changes in stool frequency and density. There are also weight loss and decreased appetite. Abdominal pain, cramping, and urging (tenesmus) are also common.
• Primary sclerosing cholangitis- a rare collagen disease, accompanied by inflammation and blockage of the bile duct, liver ducts and gallbladder. Later, yellow skin color may appear (jaundice), fever, chills and / or itching of the skin. Bacterial infections resulting from ulcerative colitis, Crohn's disease and / or vasculitis, may be associated with the cause of the blockage of the bile ducts in this disease.
• Chronic erosive gastritis - an inflammatory disease characterized by multiple lesions of the gastric mucosa. Symptoms of the disorder may include a burning or heavy feeling in the stomach, mild nausea, vomiting, loss of appetite, and / or weight loss. In severe cases, bleeding from the stomach can be so extensive that it leads to anemia.
• Irritable bowel syndromealso known as spastic colon, is a common digestive disorder that affects both the small and large intestines. Patients with irritable bowel syndrome who have "painless diarrhea" may have an urgent need for a bowel movement when it occurs.

Diagnostics

The physician suggests a diagnosis of tropical sprue in a person with anemia and symptoms of malabsorption, living in one of the regions in which the disease usually occurs or who recently visited such a region.

The doctor confirms the diagnosis by taking a tissue sample (biopsy) from the small intestine with an endoscope (a flexible probe used to visualize examination, which is equipped with a light source and a camera, and through which miniature forceps can be inserted), and examining the tissue under microscope. The doctor can identify some characteristic changes in the patient's small intestine. Usually do stool analysisto rule out parasitic or bacterial contamination as a cause.

Blood tests are done to check for malnutrition.

Standard treatments

Treatment for tropical sprue includes the use of folate, cobalamin, and antibiotics such as tetracycline, oxytetracycline, or ampicillin. The dosage of these drugs depends on the severity of the disease, as well as on the patient's response to therapy. Combination therapy with folic acid and tetracycline appears to rapidly reduce the severity of symptoms as well as heal unhealthy tissue in the small intestine. Other nutrients (eg iron, vitamin B12) can be given as needed. The diarrhea associated with this disorder can be controlled with antidiarrheal drugs.

Prognosis and complications

The prognosis for the sprue is generally good.

The acute form of the disease, complicated by fluid and electrolyte deficiency, is rarely fatal. The incidence of this complication is unknown but appears to be declining. Chronic illness with severe malabsorption and anemia can also lead to death, but this usually occurs in patients with underlying medical conditions.

Lilia Khabibulina/ article author