Gastroenteritis in children: Part 1. Diagnosis.

Acute gastroenteritis in children is a major cause of morbidity in the United States. Viral infections, primarily from rotavirus, cause 75 to 90 percent of cases. The remaining infections are largely bacterial, with as many as 10 percent of cases secondary to diarrheagenic Escherichia coli. The history and physical examination of children with gastroenteritis should focus on assessing for the presence and degree of dehydration and determining the underlying etiology. The child's weight during the illness versus posttreatment is often used to evaluate degree of dehydration retrospectively. The three examination signs that best suggest dehydration in children are an abnormal respiratory pattern, abnormal skin turgor, and prolonged capillary refill time, although parental report of the child's history is also helpful in the assessment. In general, measuring serum electrolyte levels usually is unnecessary in children with mild to moderate dehydration. Laboratory tests are recommended only when severe dehydration is suspected; in such cases, intravenous fluids would be warranted. Although it is not necessary to routinely obtain stool cultures, they should be collected if diarrhea is persistent.