Always remember that acute gastroenteritis in children is a diagnosis of exclusion. Be especially careful about making the diagnosis in a child who only has vomiting. Be sure to consider other serious badness like diabetic ketoacidosis, increased intracranial pressure, or surgical abdomen.
For an outstanding and clear article on this subject please see MMWR, Managing Acute Gastroenteritis Among Children. Nov. 21, 2003, Vol. 52.
Another useful article is Acute gastroenteritis: from guidelines to real life, Clin Exp Gastroenterol. 2010; 3: 97–112. This article, the European Guidelines * cited below, and the 2013 article, Treatment of acute gastroenteritis in children: an overview of systematic reviews of interventions commonly used in developed countries, all recommend consideration of po ondansetron in certain children with vomitting to increase the success rate of oral hydration therapy.
Note: In every patient with vomiting but without diarrhea, it is very important to consider other diagnoses besides acute gastroenteritis.
The Centers for Disease Control (CDC) along with the American Academy of Pediatrics (AAP) adopted Oral Rehydration Therapy (ORT) as the therapy of choice for patients who have:
The key to success with ORT is frequent small amounts of an approved Oral Rehydration Solution (ORS), given over a 4-6 hour time period. ORT will be initiated within the hospitals and clinics. However, the patient may be discharged prior to the completion of total rehydration. The entire guideline follows:
* If vomiting persists, three or more times during first two hours of ORS attempt, consider insertion of small naso-gastric feeding tube or IV hydration. Prior to feeding tube placement, consider obtaining abdominal x-ray to evaluate for bowel obstruction or ileus as the possible cause of persistent vomiting.
**In the emergency department or outpatient clinic, consider discharging patient after completion of two to three hours of oral rehydration therapy. Instruct parent to complete ORS at home and advance to normal diet as soon as tolerated. Instruct parent to return to clinic or ED if patient not tolerating ORS at home or if condition deteriorates.
Calculate total volume deficit:
500 mL over four-hour time period + volume for stools
1000 mL over four-hour time period + volume for stools
First hour of therapy:
After first hour of therapy:
Second hour of therapy:
Continue to add 10mL/kg for each diarrhea stool to the total four-hour volume.
If patient tolerates total volume instruct parent to introduce normal diet for age when patient is considered rehydrated.
If patient does not tolerate normal diet, continue ORS for another four to eight hours, and advance to normal diet as soon as possible
IV Rehydration Example:
Practice Parameter: The Management of Acute Gastroenteritis in Young Children. Pediatrics, Vol. 97 (3), March 1996 [Please note that this guideline has been retired and the most current AAP Guideline is Managing Acute Gastroenteritis Among Children: Oral Rehydration, Maintenance, and Nutritional Therapy. Centers for Disease Control and Prevention, Pediatrics 2004;114;507.
These guidelines do not establish a standard of care to be followed in every case. It is recognized that each case is different and those individuals involved in providing health care are expected to use their judgment in determining what is in the best interests of the patient based on the circumstances existing at the time.
It is impossible to anticipate all possible situations that may exist and to prepare guidelines for each. Accordingly these guidelines should guide care with the understanding that departures from them may be required at times.
*There two recent European pediatric guidelines on acute gastroenteritis:
(1) European Society for Paediatric Gastroenterology, Hepatology, and Nutrition/European Society for Paediatric Infectious Diseases Evidence-based Guidelines for the Management of Acute Gastroenteritis in Children in Europe, Journal of Pediatric Gastroenterology and Nutrition46:S81–S184 # 2008 by European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition
(2) 2009 Diarrhoea and Vomitting Caused by Gastroenteritis: Diagnosis, Assessment and Management in Children Under 5 Years by the (British) National Institute for Health and Clinical Excellence (NICE). 2009.