WORKUP	Section 5 of 10
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Lab Studies:

• Serum laboratory studies may help assess the severity of volume depletion, guide volume replenishment, and address electrolyte abnormalities.

• Mildly-to-moderately depleted patients generally do not require serum studies. Patients who require IV replenishment should have laboratory studies drawn including serum electrolytes, bicarbonate, BUN, creatinine, and glucose.

• Electrolytes

• Abnormal sodium values require slow correction towards normonatremia.

• However, severe hyponatremia should be corrected quickly in patients who are actively seizing but only to the extent required to abate the seizure.

• Following this, slow correction over 48 hours is warranted to achieve normal values.

• Normonatremic volume depletion can be vigorously corrected with IV fluids.

• Very low bicarbonate values are indicative of hypoperfusion, stool losses, or both.

• The higher the BUN/creatinine ratio, the worse the volume depletion.

• Glucose

• Poor intake may result in a relative hypoglycemia.

• Stress-related glucocorticoid release may result in a relative hyperglycemia.

• New onset diabetes may present as vomiting and volume depletion.

• Hypernatremic dehydration may present with hyperglycemia, which may confuse the diagnosis.

• Consider blood gases (eg, arterial blood gasses [ABG], venous blood gasses [VBG], and capillary blood gasses [CBG]) in the workup of severe volume depletion, shock, or diabetic ketoacidosis.

• Consider liver function tests (LFTs) in the workup of hepatitis.

• Consider amylase/lipase levels in the workup of pancreatitis.

• Urine studies are useful to grade severity of volume depletion. Urine tests also should be considered in the workup of gastroenteritis, urinary infection, diabetic ketoacidosis, or renal tubular acidosis.

• Specific gravity of 1.001-1.015 indicates normal-to-mild volume depletion; 1.020-1.025, moderate depletion; and 1.030 or more, severe depletion.

• Newborn infants may have a falsely low specific gravity, as their kidneys may not yet be able to concentrate urine.

• Ketonuria is typical of anorexia. Large ketones may suggest diabetes.

• Testing the stool for blood (guaiac test) may be useful in selected patients.

• Throat cultures should be considered in the setting of abdominal pain and fever. (Group A streptococcal pharyngitis often presents in this fashion.)

• Stool studies
  • Rotavirus antigen is routinely available in many laboratories.

  • Stool red cells or leukocytes in the workup of Salmonella, Shigella, Yersinia, and Campylobacter gastroenteritis

Imaging Studies:

• Abdominal films are not routinely needed.

• Consider obtaining flat plate and upright views of the abdomen when the clinical differential includes appendicitis, small bowel obstruction, peritonitis, or renal calculi.

	TREATMENT	Section 6 of 10
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Prehospital Care: Prehospital care should emphasize rapid transport to a facility with pediatric expertise.

• Children with gastroenteritis rarely require IV fluids in the prehospital setting.

• Severe shock, uncommon in the setting of gastroenteritis, warrants prehospital IV access.

Emergency Department Care: The initial assessment should evaluate the degree of volume depletion.

• Oral replenishment has an important role in resuscitation�particularly in the developing world where resources for IV volume replenishment are scarce.

• Oral rehydration therapy

• Several solutions are available commercially.

• Glucose should be given in addition to electrolytes due to the physiologic transport mechanisms for transmembrane fluid absorption mediated by glucose.

• Volume replenishment generally occurs over 8 hours.

• Oral rehydration therapy (ORT) is recommended only for selected patients. Children must be cooperative and have caregivers available to instruct and administer the oral fluids.

• ORT is not used routinely in Western EDs due to time constraints, but it is a major treatment modality in the developing world.

• It is effective for patients with severe volume depletion. ORT was originally (and still is) used to treat volume depletion associated with cholera epidemics.

• For readers in the developing world or in areas without access to IV therapy, one simple recipe for oral rehydration is as follows:

• In 1 L of water, add 2 level tablespoons of sugar or honey, 1/4 teaspoon of table salt (NaCl) and 1/4 teaspoon of baking soda (bicarbonate of soda). If baking soda is not available, use another quarter teaspoon of table salt instead. If available, add 1/2 cup of orange juice, coconut water, or a mashed ripe banana to the drink. The water is safer if boiled, but do not delay therapy to do this if the child is very ill.

• Before giving the drink, taste it to be sure it is not saltier than tears.

• Give this drink in sips (1 sip every 5 min) around the clock until normal urination returns.

• A small child needs at least 1 glass of replacement for every watery stool.

• In severe volume depletion or failed oral rehydration, obtain vascular access, send serum electrolytes, and give 20 mL/kg bolus of isotonic sodium chloride solution or lactated Ringer solution. Then give dextrose 5% in 0.5 isotonic sodium chloride solution at a rate to correct the volume deficit over 8 hours if the sodium is within normal limits.
  • To replace losses, moderate volume depletion requires 50-90 mL/kg and severe depletion requires 100-130 mL/kg.

  • Ongoing losses must be monitored and replaced.

• Volume status should be reevaluated frequently.
  • Urine specific gravity can be used with the clinical signs to guide further volume replacement.

  • After the initial IV fluid bolus, oral rehydration should again be attempted.

  • Children who demonstrate that they can tolerate oral hydration can eventually be discharged from the ED.

  • Children who are severely depleted or who cannot tolerate oral rehydration should be admitted and observed until oral rehydration is tolerated and volume losses have been replaced.

• Patients with severe volume depletion who fail oral hydration require IV fluid therapy.

• Consider nasogastric tubes in patients who meet the following criteria:
  • Moderate-to-severe volume depletion

  • Failed oral hydration

  • Failed multiple attempts at IV access

• Oral rehydration fluids can be administered (via pump or in small increments) in lieu of IV fluids.

• Intraosseous access is used in patients with shock when IV access is impossible. Such access rarely is necessary in dehydration secondary to gastroenteritis.

Consultations:

• A pediatric surgeon should be consulted when considering appendicitis, intussusception, volvulus, or malrotation.

• Gastroenterology could be consulted in the setting of ongoing gastrointestinal bleeding, diagnostic dilemmas, or gastroesophageal reflux.

	MEDICATION	Section 7 of 10
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Antidiarrheal medications are not recommended in the treatment of gastroenteritis. In the setting of gastritis, symptomatic therapy may be considered and is occasionally useful in clarifying the diagnosis of gastritis.

H2-blocker therapy can be considered in the setting of gastroesophageal reflux after consultation with the primary care provider or gastroenterologist.

• IV hydration should be guided by calculations of fluid replacement based upon the clinical estimate of volume depletion.

• In some patients, special solutions need to be ordered to correct electrolyte and acid-base abnormalities.

Further Outpatient Care:

• Parents should be taught to recognize signs of volume depletion (eg, decreased urine output, lethargy, dry mouth, poor intake). Parents often focus on the frequency of vomiting and diarrhea instead of on patient volume status.

• Parents should be given clear instructions on amounts and types of fluids to be given during the course of the illness.

Patient Education:

	MISCELLANEOUS	Section 9 of 10
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Bibliography

Medical/Legal Pitfalls:

• Failure to diagnose appendicitis, intussusception, or small bowel obstruction places patients at risk of serious complications (including death).

• Clinical presentations that include these diagnoses as considerations should be thoroughly investigated and the clinician's evaluation clearly documented.

• Antidiarrheal medications have adverse effects and generally are not necessary.