Category Archives: Diarrhea : Part 2

How can we battle the scourge of diarrhea: BASIC MECHANISMS OF DIARRHEA (Part 2)

The segregation of secretory and absorptive functions allows their simultaneous expression, and thus the minute-to-minute control of luminal fluidity based on physiological demands related, for example, to the ingestion of a meal. When considered as a whole, however, the balance of fluid and electrolyte transport in the gut is normally absorptive. Very little (less than 200 mL) of the approximately 9 L of fluid presented to the intestine on a daily basis (from either oral intake or various secretions) is lost in the stool . In the setting of diarrhea, on the other hand, this normal balance is lost. The absorptive reserve capacity of the intestine is overwhelmed and the amount of water lost to the feces increases, in some cases dramatically (eg, losses of up to 20 L/day in cases of cholera). Continue reading

How can we battle the scourge of diarrhea: BASIC MECHANISMS OF DIARRHEA (Part 1)

foodborne infectionsIn addition to foodborne infections, many other intestinal disorders are associated with diarrheal symptoms. Chief among these in terms of numbers are likely the functional bowel disorders, where the etiology of diarrhea is unknown but may relate to fundamental changes in intestinal motility. Other diarrheal diseases, on the other hand, may be associated with a significant degree of mucosal, and specifically, epithelial dysfunction. Examples include the diarrhea associated with inflammatory bowel diseases and food allergies, and iatrogenic diarrhea associated with the use of broad-spectrum antibiotics and/or acquired in the hospital setting that is most commonly ascribed to overgrowth of Clostridium difficile . But no matter what the cause, an understanding of most diarrheal illnesses rests on knowledge of basic intestinal transport mechanisms. Continue reading

How can we battle the scourge of diarrhea: THE SCOPE OF THE PROBLEM

The burden of diarrheal diseases, and particularly those caused by enteric infections, is immense. Infections are estimated to account for 3 to 4 billion cases of diarrhea each year, and up to 4.3 million deaths in children under the age of five years . Even in developed countries, the very young, the very old, institutionalized individuals, and those persons with compromized immune systems are at risk for severe or even fatal outcomes of diarrheal illness . In fact, foodborne diseases alone have been estimated to cause approximately 5000 deaths annually in the United States, along with more than 300,000 hospitalizations and more than 76 million episodes of diarrheal illness . Only a fraction of these cases involve known pathogens, but, of these, more than 90% are attributable to three main causes – Norwalk-like viruses, Campylobacters and nontyphoidal Salmonella species . Nontyphoidal Salmonellae also account for almost a third of food-related deaths from diarrheal illness. Continue reading

How can we battle the scourge of diarrhea?

Diarrheal diseasesDiarrheal diseases have been a scourge to humanity throughout recorded history. In the Western world, diarrhea may be only an inconvenience, although one that makes the sufferer miserable and which has considerable economic impact . In developing countries, on the other hand, diarrheal diseases are second only to pneumonia as a cause of infant mortality beyond the neonatal period . Moreover, even in the absence of mortality, diarrheal diseases in infancy have demonstrable long term consequences, including malnutrition, reduced physical fitness and impaired cognitive function and school performance . The toll such diseases take on human capital is therefore immense and, even in developed countries, several groups are at increased risk for severe outcomes of diarrheal illnesses, and there is evidence that disease incidence is increasing. Many diarrheal diseases are infectious in origin, and the rapid emergence of antibiotic resistance among causative pathogens is lending increased urgency to the search for a greater understanding of disease pathogenesis in the hope of developing new treatments. Continue reading

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