A complete history is necessary to determine the severity of

illness and to identify the type of dehydration present.

Obtain as much information from the child, and elicit

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CHAPTER 51

further details and clarifications from the parent or care ­

giver. Obtain a detailed description of intake (types of

liquids and solids, volume, frequency) and output of urine

(frequency, amount, color, odor, hematuria), stool

(number, consistency, presence of blood or mucous), and

emesis (frequency, volume, bilious or nonbilious,

hematemesis). Estimate urine output by the number and

saturation of wet diapers in infants and young children.

Note the presence of abdominal pain (duration, location,

intensity, quality, and radiation). Inquire about weight loss

and activity level. Note the time interval of symptoms. The

last episode of vomiting is important in determining when

the initiation of an oral trial is advisable.

Ask about associated symptoms (fever, headache, neck

pain, throat pain, dysuria, urinary frequency, rash). Travel

and recent antibiotic use are also pertinent.

Note underlying diseases that could contribute to dehydration (kidney disease, diabetes mellitus, cystic fibrosis, hyperthyroidism). Contact with ill people and daycare attendance

should be considered. Important elements of the past medical

history include immunocompromise and malignancy.

� Physical Examination

The examination begins with assessment of the general

appearance of the child. Lethargy or listlessness can warn

of impending circulatory collapse. Examine the throat for

erythema, ulcerations, or tonsillar exudates. Assess the

abdomen for tenderness, rebound, or guarding.

Neurologic exam should include mental status, cranial

nerves, strength, and reflexes. Altered mental status or

focal neurologic findings can indicate increased intracra ­

nial pressure. Capillary refill and skin turgor should be

noted. The gold standard for the diagnosis of dehydration

is measurement of acute weight loss. True pre-illness

weight is rarely known in the acute care setting. An

estimate of the fluid deficit is thus made based on clinical

assessment ( Table 5 1 -1). Any of the two following findings

are predictive of clinically significant dehydration in children: ill appearance, absence of t ears, dry mucous mem ­

branes, and delayed capillary refill ( > 2 seconds). Other

important considerations are abnormal respiratory

pattern and skin tenting.

Vital signs are an important objective measure and can

be normal in a child with dehydration. The first sign of

mild dehydration in children is tachycardia. Hypotension

is a late sign of severe dehydration.

DIAGNOSTIC STUDIES

� Laboratory

Laboratory studies are not required if the etiology is apparent and mild-to-moderate dehydration is present. A bedside glucose is indicated for all infants and children with

altered mental status. Blood sugar may be low (poor

intake) or high (diabetic ketoacidosis [DKA) ). With moderate-to-severe dehydration, electrolyte abnormalities may

point to a specific diagnosis: high K (congenital adrenal

hyperplasia, renal failure), low K (pyloric stenosis), low

bicarbonate (acidosis, HC03 loss in diarrhea), high blood

urea nitrogen/creatinine (renal hypoperfusion). Urinalysis

may show glucose, ketones, or signs of infection. Urine ­

specific gravity may be elevated in patients with dehydra ­

tion, but it is not a reliable measure. Serum sodium should

be determined because hypo/hypernatrernia requires spe ­

cific treatment regimens.

� Imaging

No imaging is required for most patients presenting to the

ED with dehydration. Consider flat/upright abdominal

x-rays if there is suspicion for obstruction. Ultrasound or

computed tomography ( CT) scan of the pelvis is indicated

if appendicitis suspected. Noncontrast head CT scan is

indicated when evaluating severe headache or if exam

reveals signs of intracranial pressure.

Table 51-1. Cli nical assessment of severity of dehydration in the pediatric patient.

Signs and Symptoms Mild (3-5% body weight) Moderate (5-1 0% body weight) Severe (>l OOfo body weight)

Mental status Alert/restless Irritable and drowsy Lethargic

Respirations Normal Deep ± rapid Deep and rapid

Pulse Normal Rapid and weak Weak to absent

Blood pressure Normal Normal with orthostasis Low

Mucous membranes Moist Dry Very dry

Tears Present Decreased Absent

Skin turgor Pinch and retract Tenting Tenting to doughy

Urine output Normal Decreased Absent

Capillary refill <2 sec 2-3 sec >3 sec

MEDICAL DECISION MAKING

History and physical examination are generally sufficient

to identify signs or symptoms of dehydration. Shock needs

immediate recognition and treatment with fluid resuscitation. Determine severity of dehydration using clinical

assessment (Figure 51-1).

The underlying cause of dehydration should be identified,

and electrolyte abnormalities require correction. Further testing is guided by clinical suspicion of more serious problems.

TREATMENT

Identify patients with signs of shock and resuscitate with

fluid immediately (20 mL/kg normal saline [NS] or

Lactated Ringer's over a 20 - to 30-minute period). Reassess

and repeat fluid bolus until perfusion is adequate and vital

DEHYDRATION

signs normalize (fluid bolus x 3 if necessary). Urine output

is the most important indicator of restored intravascular

volume (minimum = 1 mL/kg!hr). If 60-80 mL/kg of isotonic fluid is given with no improvement, consider other

causes of shock (sepsis, hemorrhage, cardiac disease). Treat

hypoglycemia promptly (2.5 mL/kg of 10o/o dextrose or

1 mL/kg of 25o/o dextrose). Once vital sign abnormalities

are corrected, the rate of fluid administration for treatment

is determined by the estimated fluid losses plus ongoing

maintenance fluid requirements (Table 51-2).

The literature supports the use of a single dose of oral