Causes of isolated diarrhea
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Common Infectious Causes of Isolated Diarrhea
Isolated diarrhea, meaning diarrhea without other major symptoms, is most often caused by infections from bacteria, viruses, or parasites. Among bacterial causes, diarrheagenic Escherichia coli (DEC) is frequently identified as a leading cause, especially in children under five years old. The most common DEC pathotypes include enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), and, less frequently, enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and enterohemorrhagic E. coli (EHEC) 67810. Other important bacterial pathogens include Salmonella spp., Shigella spp., Campylobacter spp., Aeromonas spp., and Enterobacter spp. 2345+1 MORE.
Parasitic infections are also significant, with Entamoeba histolytica, Cryptosporidium spp., and Giardia lamblia being common causes, particularly in children and in regions with poor sanitation 48. Viral causes, such as rotavirus A, are especially important in young children .
Less Common and Rare Causes: Isolated Colonic Amyloidosis
While infections are the most frequent causes, rare non-infectious conditions can also present as isolated diarrhea. One such example is localized gastrointestinal amyloidosis, where abnormal protein deposits in the colon can cause chronic watery diarrhea without other systemic symptoms. This condition is rare and usually considered only after more common causes have been excluded .
Patterns of Antimicrobial Resistance in Diarrheal Pathogens
A notable concern in the management of infectious diarrhea is the high rate of antimicrobial resistance among bacterial isolates. Many studies report that DEC and other bacterial pathogens show resistance to commonly used antibiotics such as ampicillin, tetracycline, and trimethoprim-sulfamethoxazole, with a significant proportion being multidrug-resistant 67810. This highlights the importance of appropriate antibiotic stewardship and the need for targeted therapy based on susceptibility testing.
Conclusion
In summary, the most common causes of isolated diarrhea are infectious agents, particularly diarrheagenic E. coli, Salmonella, Shigella, Campylobacter, Aeromonas, and various intestinal parasites. Rarely, non-infectious conditions like localized amyloidosis can be responsible. High rates of antimicrobial resistance among bacterial pathogens further complicate treatment, emphasizing the need for careful diagnosis and management.
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