Pediatric emergency medicine trisk 0519 0519
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translocation of fluid such as occurs with major burns or ascites ( Table 22.1 ).
Many presentations of dehydration are a combination of different causes of fluid
imbalance.
EVALUATION AND DECISION
The first step in evaluating a child with dehydration is to assess the severity or
degree of dehydration, regardless of the cause ( Table 22.2 ). Most children with
clinically significant dehydration will have two of the following four clinical
findings: (i) capillary refill greater than 2 seconds, (ii) dry mucous membranes,
(iii) no tears, and (iv) ill appearance. The more dehydrated a patient is, the more
hypovolemic they are and the more likely they are progressing toward shock.
Minimal, mild–moderate, and severe dehydration correspond to impending,
compensated, and uncompensated states of shock, respectively (see Chapter 10
Shock ). If there is severe dehydration or uncompensated shock, the child must be
treated immediately with isotonic fluids to restore intravascular volume, as
detailed later in this chapter.
History
A thorough history aids in assessing child’s degree and etiology of dehydration (
Fig. 22.1 ). Attention should be paid to the child’s output and intake of fluids and
electrolytes. Overt GI losses from diarrhea and vomiting are the most common
causes of dehydration in children (see Chapters 23 Diarrhea and 81 Vomiting ).
However, other diagnoses with these symptoms should be considered, especially
if the patient presents with only vomiting (i.e., diabetes ketoacidosis and urinary
tract infections) ( Table 22.3 , Chapter 81 Vomiting ). Decreased oral intake may
occur for various reasons, including painful oral lesions, limited resources, or
altered mental status. Insensible losses can occur due to fever, high ambient
temperatures, sweating, and hyperventilation. It is important to note whether there
is any underlying disease that would contribute to dehydration (e.g., cystic
fibrosis, diabetes insipidus, hyperthyroidism, renal disease).
Asking the parents about documented weight loss, amount of urine output, and
the presence or absence of tears is helpful in determining the severity of the
dehydration. Although decreased urine output is an early sign of dehydration,
only 20% of patients with the complaint of decreased urine output will be
dehydrated. With dehydration, one expects to find oliguria or anuria if normal
renal concentrating function remains intact. Severe oliguria or anuria may also,
however, be manifested if severe dehydration and shock has led to acute renal
failure (see Chapter 100 Renal and Electrolyte Emergencies ). The unexpected
discovery of polyuria points to diabetes mellitus or insipidus, adrenal
