Diarrhea

The normal water content value in stools is approximately 10 mL/kg/day in infants and young children or 200 g/day in teenagers and adults. Diarrhea is the augmentation of water content in stools because of an imbalance in the normal functioning of physiologic processes of the small and large intestine responsible for the absorption of various ions, other substrates, and, consequently, water.

Acute diarrhea is the onset of 3 or more loose or watery stools a day lasting 14 days or less. However, chronic or persistent diarrhea is labeled when an episode lasts beyond 14 days. Infection commonly causes acute diarrhea. Noninfectious etiologies become more common as the duration of diarrhea becomes chronic. This distinction is important because treatment and management are based on the duration and specific etiology. Rehydration therapy is an important aspect of managing any patient with diarrhea. Prevention of infectious diarrhea includes proper handwashing to prevent the spread of infection.

The term "acute gastroenteritis" is synonymously used with "acute diarrhea"; however, the former is a misnomer. The term gastroenteritis signifies both gastric and small intestinal involvement, whereas, practically, it is rarely seen in acute diarrhea, even if it is the infective form of diarrhea. Additionally, enteritis is also not always present. Examples of infectious diarrhea without enteritis include cholera and shigellosis. Hence, using the term acute diarrhea instead of acute gastroenteritis is more clinically appropriate.