sprue (TS) is a clinical entity of unknown etiology characterized by an
acquired chronic diarrheal illness and malabsorption that affects
indigenous inhabitants and expatriates, either long-term residents or
short-term visitors, in the tropical countries.
mainly in Asia, including Sri Lanks, Southern India, Malaysia, Indonesia,
Hong Kong and China, some Caribbean Islands, Puerto Rico and parts of
Pathogenesis: The exact pathogenetic
sequence of Tropical
sprue remains incompletely characterized.
disturbed gut motility, and hormonal and histopathologic abnormalities
contribute to the development of TS in a susceptible host.
malabsorption (TM; tropical sprue) starts with an acute intestinal
infection (bacterial, viral, or parasitic) which can affect predominantly
the small or the large intestine.
Miscellaneous invasive pathogens cause
subsequent enterocyte damage affecting the entire small intestine and, to
a lesser extent, the colon.
Enteroglucagon, a tropic hormone, is then
liberated and reaches a high plasma concentration.
Further bacterial colonisation (in the lumen and also at the
enterocyte surface) is encouraged.
Continuing enterocyte damage is
worsened by coexistent folate depletion, which is initiated at the onset
of disease; body stores of folate reach a low concentration by 3 or 4
The cycle continues until the bacterial overgrowth is eliminated
with an antibiotic (eg, tetracycline), or mucosal integrity recovers
(hastened by oral folic-acid supplements), or both.
presentation: Tropical sprue presents with
diarrhea, anorexia, weight loss, and megaloblastic anemia.
Remissions and relapses
are a characteristic feature. In severe cases 10 stools or more may be
Tropical sprue should be
considered in the differential diagnosis of chronic diarrhoea in patients
with a history of travel in tropical regions.
The most frequent medical
problem that travellers to the tropics experience is diarrhoea with an
incidence of 30%.
A small proportion of these patients eventually present
with chronic diarrhoea.
At that moment, the relation to their previous travelling may not be immediately clear.
One of the causes of this chronic diarrhoea to be considered is tropical sprue.
the intestinal changes range from near normal to severe diffuse enteritis.
closely resemble those of coeliac disease, although they tend to be less
villous atrophy has been a constant finding.
The jejunal villi
are blunted or, rarely, absent and there is a subepithelial infiltration
with plasma cells and lymphocytes.
In some cases
there is enlargement of the nuclei of epithelial cells.
In severe cases the ileum
is also affected.
These changes are
associated with malabsorption of fat, protein, carbohydrate and vitamins
and the presence of diarrhoea which may lead to depletion of water,
electrolytes, iron and calcium.
anemia is common with megaloblastic change in the bone marrow due to
Vitamin B12 deficiency
takes longer to develop.
Mild changes in
the jejunal mucosa are common in asymptomatic indigenous peoples, without
gross malabsorption, throughout the tropics.
features and the history of residence in an area noted for tropical sprue
will suggest the correct diagnosis if care is taken to recognise the early
and the mild case as well as the late presentation.
malabsorption should be sought.
erythrocyte levels of folate are low.
Anaemia may also
be hypochromic from defective absorption of iron.
shows shows partial villous atrophy which is not specific for tropical
Jejunal mucus and
fluid is examined to exclude parasites.
Barium meal and
follow through examinations are necessary only to exclude other disease.
diagnosis is from other forms of steatorrhoea.
causes in the tropics are infections of the intestine with
Giardia intestinalis, Stongyloides stercoralis or Capillaria philippinensis.
Early symptoms or sprue may errorneously be attributed to
The response to treatment to
tetracycline and folic acid has been uniformly successful.