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Sir William MacGregor, MD, at the end of his term as Papua New Guinea's colonial governor, wrote: "Dysentery causes more deaths than any other disease in tropical countries. No other malady is so universally distributed and of such constant occurrence … [Dysentery has become] the chief agent in the rapid depopulation of the Pacific."1

Rehydration does not have the drama of other medical interventions—but it saves more lives than all other disease treatments combined.


Diarrhea causes most cases of lethal dehydration, especially among infants and children. Acute diarrhea is ≥3 loose or watery stools/day or a definite decrease in stool consistency and an increase in stool frequency for the individual. The volume of fluid lost through stools can vary from 5 mL/kg body weight/day (approximately normal) to ≥200 mL/kg body weight/day.2 Because of the use of oral rehydration therapy (ORT), the annual worldwide deaths from diarrhea have decreased from >5 million in 1978 to 2.6 million in 2009 (1.1 people >5 years old and 1.5 children <5 years old).3

Pediatric Dehydration

Assessing a child's level of dehydration is a clinical diagnosis. This assessment should be no harder in austere situations than in standard practice—except that the confounder of malnutrition may play a big role in a child's appearance. Laboratory studies, including serum electrolytes, are usually unnecessary.4 Stool cultures are indicated in dysentery, but are not usually indicated in acute, watery diarrhea for an immunocompetent patient.

Table 11-1 is a pediatric dehydration assessment tool that is easy to use and has good inter-rater reliability.5 It relies on: (a) a change in mental status, (b) dry mucous membranes, (c) poor skin turgor or tenting, and (d) tachycardia or hypotension.6

Table 11-1 Clinical Pediatric Dehydration Scoring System

Dehydration versus Septic Shock in Malnourished Children

In children with severe malnutrition, dehydration and septic shock are difficult to differentiate. Both present with signs of hypovolemia and worsen without treatment. Rather than using the normal signs to assess dehydration, use the signs and symptoms presented in Table 11-2. Otherwise, dehydration will be overdiagnosed and its severity overestimated, and it will be difficult to recognize and treat children with both dehydration and septic shock.7

Table 11-2 Differentiation of Dehydration and Shock in the Malnourished Child

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