by Dr. Moshe Ipp December 1997
Acute gastroenteritis remains one of the most common illnesses affecting infants and children in Canada and the world. Although most children have mild symptoms with little or no dehydration, a substantial number are affected more seriously. Almost 10% of hospitalizations of children younger than 5 years of age are because of diarrhea and it is estimated that almost ¼ of a million children are hospitalized each year with gastroenteritis. The average child under age 5 experiences 2.2 diarrheal episodes per year; children attending Day Care Centers have an even higher incidence. There are surveys to show that many health care providers do not follow recommended procedures for the optimal management of children with diarrhea.
Replacement of fluid and electrolyte losses is the critical central element of effective treatment of acute diarrhea. Oral rehydration therapy (ORT) is the preferred treatment of fluid and electrolyte losses caused by diarrhea in children with mild (3-5%) and moderate (6-9%) dehydration. While intravenous therapy was the first successful routine method of correcting fluid and electrolyte losses following diarrhea, it became clear in the late 1960's that the use of oral glucose-electrolyte solutions were equally successful in treating patients with cholera in Bangladesh and India. Over the last decade, a series of studies from developed countries have proven the effectiveness of ORT compared with intravenous therapy in children with diarrhea from causes other than cholera.
Oral rehydration takes advantage of the glucose-coupled sodium transport system. This is a process for sodium absorption which remains intact in infective diarrheas due to viruses or enteropathogenic bacteria. It has been shown that glucose enhances sodium and secondarily water transport across the mucosa of the upper intestine. The amount of fluid absorbed depends on three factors which makes the composition of rehydration solutions critical. Maximal water uptake occurs with a sodium concentration from 40 to 90 mmol/L, a glucose concentration from 110 to 140 mmol/L and in a solution with an osmolality of about 290 mOsm/L.
Increasing the sodium beyond 90 mmol/L may result in hypernatremia (chicken broth may contain 250 mmol/L of sodium and is contraindicated as a rehydration fluid). Increasing the glucose concentration beyond 200 mOsm/L will increase the osmolality of the solution and may result in a net loss of water. For these reasons the following clear liquids are not appropriate for oral rehydration therapy:
Another reason why fruit juices and pop are not efficacious in the treatment of diarrhea is because their sodium content is too low (cola 2 mmol/L, apple juice 3 mmol/L, sports beverages 20 mmol/L) For optimal therapy the carbohydrates: sodium ratio should not exceed 2:1 in the rehydraton solution.
These children should continue to be fed age appropriate diets. Several studies have now demonstrated that unrestricted diets do not worsen the course or symptoms of mild diarrhea. In fact a recent meta-analysis was performed to evaluate the use of lactose-containing feedings in children with diarrhea and concluded that 80% or more of children with acute diarrhea can tolerate full strength milk safely. Although reduction in intestinal brush border lactase levels is often associated with diarrhea, most infants with decreased lactase levels will not have clinical signs or symptoms of malabsorption. Infants fed breast milk can be nursed safely during episodes of diarrhea. In the past, the American Academy of Pediatrics recommended gradual re-introduction of milk-based formulas or cow's milk in the management of acute diarrhea beginning with diluted mixtures; this recommendation has been re-evaluated in the light of these recent data.
The classic BRAT diet which consist of bananas, rice, apple sauce and toast is well tolerated in infants with diarrhea but it is now considered that this diet is limited in nutritional quality because of low energy density, protein and fat. Current recommendations include age appropriate foods including complex carbohydrates (rice, potatoes, bread and cereals), lean meats, yogurt, fruits and vegetables. Foods to be avoided include fatty foods or foods high in simple sugars (juices and soft drinks).
The only objective measure of dehydration is the degree of the child's weight loss. If a recent accurate weight is available this is the most useful measure to calculate the percentage of weight loss and dehydration. All children with diarrhea must be weighed at the time of their initial presentation to a physician since this weight can be used for comparison over the next few days if the diarrhea is not mild and self limiting. Delayed capillary refill-time (although affected by temperature and age) should be considered a sign of significant dehydration. Urinary output and specific gravity are also helpful measures to confirm the degree of dehydration.
Since most episodes of dehydration caused by diarrhea are isonatremic, serum electrolyte measurements are considered unnecessary. However electrolytes should be measured in all children with severe dehydration and in those with moderate dehydration where the physical findings are inconsistent with the history obtained. Children with hypernatremic dehydration are often inappropriately assessed because of it's unusual clinical presentation; these children do not appear to be as unwell and as dehydrated as the history suggests, irritability and fever may be present, a doughy feel to the skin is a distinctive feature and the typical skin tenting usually associated with the more common isotonic dehydration may not be present. Hypernatremic dehydration can result from the ingestion of hypertonic liquids such as boiled milk and home made solutions to which salt has been added.
Vomiting may be an early symptom of gastroenteritis and sometimes may be the only manifestation (gastritis). The combination of vomiting and diarrhea at the same time is potentially the most serious symptoms in a child with gastroenteritis because of the combined upper and lower intestinal fluid loss. Most children with vomiting and dehydration can in fact be treated with ORT. The mainstay of therapy in the vomiting child is to administer small amounts of fluid frequently. Therapy should be initiated with 5ml aliquots given every 1 to 2 minutes. Although this technique is labor intensive it can be done by a parent and will deliver 150 to 300 ml/hour. As the vomiting lessens, larger amounts of ORT can be given after longer intervals. Once rehydration is accomplished, other fluids including milk and age appropriate foods can be introduced. If the vomiting continues despite efforts to administer ORT intravenous hydration is indicated.
It appears that children who are dehydrated rarely refuse ORT; however those who are not dehydrated may refuse the solution because of its salty taste. Consequently, children with mild diarrhea and no dehydration should be fed a regular diet and do not require ORT solutions. There are some practical techniques that can be used to induce the reluctant child to drink glucose electrolyte solutions by offering small amounts at first; this may allow the child to get accustomed to the taste. Some commercial preparations are flavored, without altering the basic composition of the fluid, and this may be more palatable for some children. Frozen ORT solutions may be given to children in the form of a Popsicle.
In children who are not dehydrated an ORT solution may not be required. These children can be continued on age appropriate feeding with an increase in their normal fluid consumption. These children are the least likely to ingest ORT. It is estimated that they should receive approximately 10 ml/kg for each stool passed. In children with mild dehydration (3-5%) 50 ml/kg of ORT should be given over a period of 4 hours. The replacement of continuing losses from stool and vomiting requires an additional 10 ml/kg for each stool passed and an estimate for the amount of vomiting. For moderate dehydration (6-9%) 100 ml/kg of ORT replacement should be administered as well as continuing losses over a 4 hour period. Children with moderate dehydration should be monitored in a supervised setting such as an emergency room, or a physician's office which has the capability of observing the child. Severe dehydration (>10%) is a medical emergency and should be treated with immediate intravenous therapy.
There are four classes of anti-diarrheal pharmacological agents, and as a general rule none should be used to treat acute diarrhea in children. These medications include the following, and are effective by altering:
Antiemetic drugs are not indicated for the management of vomiting in children with gastroenteritis.
|
PEARLS |
|
Acute gastroenteritis in children is common and has a high morbidity |
|
The use of oral rehydration solutions (ORT) have advantages over conventional therapy |
|
ORT solutions should be encouraged for rehydration purposes over fruit juices and pop which are not efficacious because of their high carbohydrate concentration, high osmolality and inadequate sodium concentration. |
|
Early re-feeding of age-appropriate foods should be encouraged. |
|
Pharmacological agents should not be used to treat acute diarrhea in children |
References
1. Pediatrics 97: No 3, March 1996
2. The Can J of Pediatrics 1: No 5, 1994.
to return to home page