Tropical Sprue and Deficiency of Vitamins B9 and B12

Tropical Sprue is a condition in which the patient has difficulty absorbing nutrients from food.  It is called tropical sprue because it is endemic in the tropics and is also diagnosed in patients who have traveled to or lived in tropical regions.  Symptoms include a persistent watery, non-bloody diarrhea that is very smelly (steatorrhea), abdominal cramping, bloating, fatigue and weight loss.  These symptoms are similar to those of celiac disease (which is also called non-tropical sprue), and often patients are initially put on a gluten-free diet.  Unlike celiac disease, tropical sprue does not respond to gluten restriction.

Clinical examination reveals fat in the stool  (characteristic of malabsorption), macrocytic anemia, and blood tests often show deficiencies in both vitamins B9 and B12.  An intestinal biopsy shows pathological changes to the shape of the intestinal villi, characteristically a blunting of the ends.  Inflammation of the intestinal tissue is also observed.

A treatment course with tetracycline usually resolves the condition, with the diahrrea and cramping stopping after a few days to a few weeks, even in patients who had it for more than a year.  Weight gain follows soon thereafter.  Since serious vitamin B12 depletion may have developed by the time the condition is diagnosed, patients are often given vitamin B12 injections.    Fatigue is one of the symptoms of deficiency of either or both vitamins B9 or B12, and that also abates once these vitamins have been replenished.  A continued deficiency of vitamin B12 can cause neurological symptoms such as disorientation and depression, and ultimately paralysis, caused by a degeneration of the spinal cord.  Even though tropical sprue

The fact that tropical sprue responds to antibiotic treatment indicates that it is probably caused by a bacterial infection.  No specific agents have been identified as of yet.  Also in some cases tropical sprue did not respond to metronidazole, although it did to tetracycline, so it may be necessary to try more than one antibiotic.  Although in principle tropical sprue is relatively easily treated, it may masquerade as celiac disease and it causes secondary vitamin deficiencies, each of which cause more symptoms.  That can make it hard to diagnose and extremely frustrating for the patient.

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