Diarrhea is one of the most serious and overlooked health issues. Globally, diarrhea is responsible for 1.1 million deaths annually in people ages 5 and over and 1.5 million deaths in children under the age of 5, according to the World Health Organization (2009).
In developing countries, children under the age of 5 have an average of three episodes per year, although some areas report as many as eight episodes per year per child. About 47% of the world’s childhood diarrhea cases occur in India, Nigeria, Democratic Republic of Congo, Pakistan, and China (CDC, 2011). In these settings, malnutrition is an important consequence, and recurrent episodes of diarrhea lead to growth faltering and failure to thrive.
Diarrheal diseases take a significant toll in the developed world as well. Every year, hundreds of thousands of Americans are hospitalized as a result of foodborne illness that may cause diarrhea. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK, 2011), the average adult in the United States has a short period of diarrhea about four times a year, which amounts to at least one case every eight seconds.
Diarrhea is a derangement in the normal net absorptive status of water and electrolyte absorption and secretion. Diarrheal diseases encompass a variety of infections caused by bacteria, viruses, protozoans, and other parasites. Routes of infection range from consuming contaminated food or water to having direct contact with someone who is sick. The swimming environment is another significant avenue of infection (CDC, 2011).
The mechanism of diarrhea is complex and depends upon the specific toxin or action of the pathogenic agent. There are some underlying pathophysiologic features. Normally, body fluids in the intestinal lumen are iso-osmotic and contain a high concentration of sodium. A significant amount of sodium per day is secreted and reabsorbed by the intestine at a rate that, in concert with kidney activity, maintains the exquisite balance of electrolytes in the blood. During gut dysfunction due to acute diarrheal illness, sodium resorption is markedly decreased, and low sodium plasma levels ensue. This can result in serious neurologic consequences and even death. An additional complication is that transport of sodium back into the intestinal epithelial cells requires co-transport of glucose or galactose; for this reason, glucose is an essential component of oral rehydration solutions (Fisher and Parsons, 1953).
Oral rehydration salts and zinc tablets are the treatment of choice for diarrhea. These interventions are estimated to have saved 50 million children in the past 25 years. With that said, developing countries, particularly regions of Africa and Southeast Asia, are disproportionately affected due to poor sanitation and lack of clean drinking water.
Generally, Westerners are protected against contact with the diseases by a complex array of regulations governing water supplies, farms, the trajectory of food from farm to fork, restaurants, and even public swimming pools. Even in developed countries where sanitation facilities and clean drinking water are a part of every community and home, there are still ways to improve. In our modern agricultural system where food grown on one side of the country may be shipped to a supermarket on the other, it has become increasingly clear that what may once have been a small, contained outbreak can turn into a wider problem.
The single most common cause of infectious diarrhea worldwide is rotavirus. Because two vaccines (RotaTeq® and Rotarix®) have been in use since 2006, a reduction in the overall frequency of diarrheal episodes is anticipated.
The established regulatory environment has not proven adequate to address this widespread health problem. Imaginative consumer education is critical; the early and aggressive use of probiotics in conjunction with conventional pharmacologic therapies may prove significant. Moreover, physicians and health-care providers must be encouraged to obtain a focused nutritional history when evaluating patients with diarrheal syndromes; irritable bowel is a label far too often applied in haste. Food intolerances, celiac sprue, and even manifestations of entities such as hereditary angioedema, the porphyrias, “abdominal migraines,” and familial Mediterranean fever can be at the root of diarrheal syndromes not otherwise accurately diagnosed.
In this era of justified concern about obesity and hypernutrition, let us not forget the life-and-death impact of diarrheal illnesses and malnutrition.
References cited in this article are available from the authors.
Peter Pressman, M.D.,
Contributing Editor LCDR, MedicalCorps, U.S. Navy,
Director Expeditionary Medicine,
Task Force for Business & Stability Operations
[email protected]
Olivia Novak,
Contributing Editor
Graduate Student in Epidemiology,
George Mason University, Fairfax. Va.
[email protected]