on 26.1.09 with 0 comments

A problem that occurs during or after a trip does not necessarily need to have a causal connection with that trip. Intestinal infections due to protozoa are cosmopolitan, though they are more prevalent in tropical countries, where the climate enables the outdoor survival of protozoa while low hygiene standards promote their transmission.

Patients are always assessed according to the degree of dehydration, the presence of fever, whether the stools contain blood or not, the presence of steatorrhoea and whether the condition is acute or chronic.

Diarrhoea is often found in association with parasitic infection, though the causal relationship should always be critically assessed. It is important to distinguish between infection and disease. Only a few species of the numerous protozoa found in the faeces are pathogenic. Plasmodium falciparum and Leishmania donovani can sporadically elicit aspecific digestive symptoms. The most frequent cause of diarrhoea is gastroenteritis (viral, bacterial, parasitic), though another aetiology (e.g. atypical malaria) should not be overlooked. Non-infectious causes such as laxative abuse, exocrine pancreas insufficiency, hyperthyroidism, coeliac disease (syn. celiac disease, gluten or gliadine hypersensitivity) and inflammatory intestinal diseases (Crohn’s, ulcerative colitis) are much less frequent. Lactose intolerance should be excluded in cases with persistent symptoms. Diarrhoea is sometimes the consequence of food containing previously formed bacterial toxins, even though the bacterium itself is no longer present or active. Examples are staphylococcal diarrhoea, ingestion of Clostridium toxins due to consumption of contaminated meat (pig-belly) and Bacillus cereus toxins (including bad rice). Rare causes such as Whipple disease (infection with the Gram-negative actinomycete Tropheryma whipplei) and endocrine tumours should only be suspected in unusual cases. The cause of some diseases (e.g. tropical sprue) is still not clear.

Category: Medicine Notes



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