Section 3 Dehydration

**37**

**Chapter 3**

**Abstract**

**1. Introduction**

and correction of dehydration.

**2. Body water distribution**

Dehydration

*Fatihi Hassan Soliman Toaimah and Fysel Manthattil*

of fluids and electrolytes with slow correction approach.

Dehydration is one of the common presentations to the general practice or emergency departments (EDs) in children having acute gastroenteritis (AGE). Assessing the severity of dehydration remains a challenge among physicians, and the dehydration scales currently available are inaccurate. The correct assessment of dehydration is the basis for proper management of acute diarrhea in children. Rapid oral rehydration therapy (ORT) over 3–4 hours remains the cornerstone treatment of AGE with dehydration. It is advisable to reserve intravenous (IV) rehydration therapy for patients with severe dehydration and for those who fail ORT. Rapid standardvolume (20 ml/kg/hour) IV bolus of isotonic solution for 1–4 hours followed by oral fluid intake or maintenance IV fluids seems to be adequate for most cases requiring IV rehydration. A minority of patients may be presented with complications due to diarrheal dehydration, such as dyselectrolytemia, which requires careful calculation

**Keywords:** gastroenteritis, dehydration, children, rehydration, pediatric, diarrhea

Dehydration is the main clinical manifestation and the most frequent complication in pediatric patients with AGE. It remains to be a common reason for ED visits, and it can lead to significant morbidity and mortality rates [1]. Management of gastroenteritis is based mainly on the proper assessment of dehydration severity

In newborn babies, 75–80% of the total body weight constitutes the total body water (TBW) (varies with the gestational age), which decreases to 67% of body weight (2/3) after the neonatal period. There is a further decrease that reaches 60% by the end of the first year, and this percentage remains the same during the rest of life. After puberty and in adulthood, TBW is 60% in males and 55% in females. The TBW is divided into two components throughout the body: intracellular fluid compartment (ICF), which constitutes 40% of TBW, and extracellular fluid (ECF), which forms the remaining 20%. The ECF comprises interstitial fluid (IF) (15% of the TBW), and the remaining 5% of the TBW comprises intravascular plasma (**Figures 1** and **2**) [2–4]. This distribution of body fluids can have an impact on the management of pediatric gastroenteritis, as most of the fluid loss in AGE comes from the ECF. This matters because ECF contains a lot of sodium (135–145 mEq), and ICF contains a lot of potassium (150 mEq). In a brief duration of illness
