Diarrhea

Causes

Diarrhea, defined as excessively liquid or frequent evacuation of feces, can be caused by numerous conditions. Infectious diseases make up the vast majority of causative factors, although diarrhea can also be caused by contaminated food, as a medication side effect (particularly antibiotics), as a symptom of colorectal cancer, and as a sign of hormonal abnormalities.

Infectious organisms causing diarrhea include viruses (rotavirus being the most common), bacteria (e.g., E. coli), and parasites (e.g., Giardia). The gastrointestinal system, particularly the small and large intestines, are naturally populated by hundreds of different strains of nonharmful bacteria, many of which help with digestion. Infectious diarrhea can be caused either when a harmful, nonnative, biological agent colonizes the intestines or when one particular strain of native bacteria is favored over the others and takes over. This second pathway is exemplified by cases of bacterial overgrowth following the administration of antibiotics. The ingested antibiotics kill off most of the natural bacterial “flora” of the gut allowing a single disease causing variety to take over and proliferate.

The principle pathway of infectious diarrhea however, occurs through the spread of dangerous organisms through the environment. Infected individuals without access to latrines or a safe sanitation system inadvertently contaminate their own supply of water, spreading the disease to other members of their communities and creating a cycle of illness. Even with access to a clean water supply, organisms in improperly disposed of human waste can be spread to food by “vectors” like mosquitoes and other insects.

Symptoms

Diarrhea by itself is often ignored by patients and considered by many to be a temporary nuisance. However, it is important to distinguish associated symptoms that indicate a more serious condition. Fever, abdominal pain, blood or mucous in the stool, nausea, and vomiting are all reasons to seek urgent medical attention. If the nausea and vomiting are severe, the patient's ability to maintain wellhydrated is at risk.

Dehydration is the biggest danger to deal with during severe episodes of diarrhea. Signs and symptoms of dehydration include lethargy, weakness, sunken eyes, an increased heart rate (greater than 110 beats per minute for a 5-year-old), and decreased urine output.

Chronic low-level diarrhea may also lead to malnutrition in children, who are unable to absorb the nutrients they need for normal growth and development.

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