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Acute gastroenteritis is a common and costly clinical problem in children. It is a largely self-limited disease with many etiologies. The evaluation of the child with acute gastroenteritis requires a careful history and a complete physical examination to uncover other illnesses with similar presentations. Minimal laboratory testing is generally required. Treatment is primarily supportive and is directed at preventing or treating dehydration. When possible, an age-appropriate diet and fluids should be continued. Oral rehydration therapy using a commercial pediatric oral rehydration solution is the preferred approach to mild or moderate dehydration. The traditional approach using “clear liquids” is inadequate. Severe dehydration requires the prompt restoration of intravascular volume through the intravenous administration of fluids followed by oral rehydration therapy. When rehydration is achieved, an age-appropriate diet should be promptly resumed. Antiemetic and antidiarrheal medications are generally not indicated and may contribute to complications. The use of antibiotics remains controversial.

Pediatric acute gastroenteritis remains an important clinical illness commonly encountered by family physicians. Its attendant problems of vomiting, diarrhea and dehydration continue to present significant risks to children and are responsible for considerable health care expenditures.

Estimates of the overall incidence of acute gastroenteritis range from 1.3 to 2.3 episodes of diarrhea per year in children under five years of age. Each year, more than 300 U.S. children die from this illness.1 In the United States alone, gastroenteritis accounts for more than 220,000 hospital admissions per year in children less than five years of age, or approximately 10 percent of hospitalizations in this age group.1 Direct costs for hospital and outpatient care are estimated to exceed $2 billion per year.1,2

Over the past two decades, pediatric acute gastroenteritis has been the subject of considerable worldwide attention and effort. Particular emphasis has been given to the development and promotion of inexpensive, easy-to-use oral rehydration solutions for the treatment of dehydration, the problem that is most responsible for morbidity and mortality in children with this illness. Despite the growing body of evidence supporting the safety and efficacy of oral rehydration solutions, they remain underutilized, and the management of gastroenteritis continues to vary considerably in the developed world.

Study results suggest that some physicians do not know the current standards for oral rehydration therapy.35 Even physicians who are familiar with these standards do not necessarily use oral rehydration therapy in their dehydrated pediatric patients.35 Common management errors include using oral rehydration solutions in children with little or no dehydration, administering intravenous rehydration therapy to children with only moderate dehydration and inappropriately withholding oral rehydration solutions or other feeding in children with vomiting.6

In an attempt to improve physicians' understanding of the management of acute gastroenteritis in children and to bring more uniformity to treatment approaches and costs in the United States, the American Academy of Pediatrics (AAP) formulated and published a practice parameter on the subject in 1996.2 The AAP's recommendations, adopted after extensive review and evaluation of the relevant literature, address three specific issues: methods of rehydration, refeeding during and after rehydration and the use of antidiarrheal agents for symptom control.

Definition and Causes

A uniform definition of acute gastroenteritis does not exist. The AAP defines acute gastroenteritis as “diarrheal disease of rapid onset, with or without accompanying symptoms or signs such as nausea, vomiting, fever or abdominal pain.”2 The hallmark of the disease is increased stool frequency with alteration of stool consistency.

Worldwide, infectious agents (viruses, bacteria and parasites) are by far the most common causes of acute gastroenteritis (Table 1).6,7 Viruses, primarily rotavirus species, are responsible for 70 to 80 percent of infectious diarrhea cases in the developed world, various bacterial pathogens account for another 10 to 20 percent of cases and parasitic organisms such as Giardia species cause fewer than 10 percent of cases.8 This distribution is affected by climate and season, as evidenced by the dramatic increase in rotavirus cases in the United States during the winter months. These winter rotavirus infections account for more than 50 percent of hospitalizations for pediatric gastroenteritis.9 Other factors that increase the risk of acute gastroenteritis in children include attendance at day care centers and impoverished living conditions with poor sanitation.8

PathogensInflammatory agentsNoninflammatory agents
VirusesRotavirus (most common)
Enteric adenovirus
Norwalk virus
BacteriaSalmonella (most common)Toxigenic Escherichia coli
Shigella (second most common)
Campylobacter jejuni
Yersinia enterocolitica (more common in Europe and Canada)
Hemorrhagic E. coli O157:H7
Clostridium difficile (iatrogenic)
ParasitesGiardia lamblia (most common)



The evaluation of the child with symptoms of acute gastroenteritis begins with a careful history to elicit information that might point to other illnesses with similar presentations. Respiratory symptoms such as cough, dyspnea or tachypnea may indicate the presence of an underlying pneumonia. Urinary frequency, urgency or pain may be symptoms of pyelonephritis, an earache may be a symptom of acute otitis media, and high fever and altered mental status may be signs of meningitis or sepsis. Factors such as travel to underdeveloped countries, exposure to untreated drinking or washing water sources, contact with animals or birds, day care center attendance, recent antibiotic treatment or even a recent change in diet may suggest other specifically treatable causes of vomiting and diarrhea.

A second goal of the history is to assess the severity of the symptoms and the risk of complications such as dehydration. The presence or absence of fever, the amount and type of oral intake, and the frequency and estimated volume of emesis or stool are important factors to consider. Fever increases insensible water loss. Emesis, stool and urine volume in excess of intake invariably leads to significant dehydration. Stool characteristics such as the presence of blood should prompt consideration of inflammatory bacterial disease and a much more aggressive work-up and intervention.10

The physical examination has two main functions: a search for signs of comorbid conditions and an estimate of the level of dehydration. The first objective can be accomplished with a careful general examination. The second objective is more difficult to achieve. The primary tasks are to assess the adequacy of perfusion and to determine whether dehydration is severe enough to cause hemodynamic instability. It may be most helpful to compare the patient's present weight with the last recorded weight in the chart, to assess the patient's orthostatic vital signs and to carefully review the patient's recent oral fluid intake.

Clinical signs may also be used to classify the patient's dehydration as mild, moderate or severe (Table 2).2,11 Evidence exists, however, that traditional clinical signs are not always reliable in determining the degree of dehydration. For example, capillary refill time can be affected by ambient temperature.12 One study13 found that only decreased peripheral perfusion, deep breathing and decreased skin turgor correlated with mild to moderate dehydration. Another study14 reported that prolonged skinfold time correlated best with the degree of dehydration, followed by altered mental status, sunken eyes and dry oral mucosa. Yet another study3 found that as many as 87 percent of children admitted to the hospital for dehydration on the basis of clinical signs had mild or no dehydration based on a comparison of their weights on admission and discharge (when they were judged to be fully rehydrated); 82 percent of these patients received intravenous rehydration therapy.

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Because of doubts about the accuracy of clinical signs of dehydration, family physicians need to remember that the dehydration categories are only an estimate. In assigning patients to a category, physicians should use all of the available clinical and historical information, not just the physical findings.


In the past, a number of laboratory studies were used to evaluate children with acute vomiting and/or diarrhea. Because oral rehydration therapy has become the preferred method of treating dehydration, routine laboratory testing is no longer necessary, although it may be helpful in individual patients or when oral replacement therapy fails.

High urinary specific gravity may indicate significant dehydration when combined with a history of decreased urine output. Serum chemistry measurements such as electrolyte, blood urea nitrogen and creatinine levels do not change the initial management approach in most patients.15 Hemodynamically stable children can be safely treated with oral rehydration therapy with only minimal risk of developing significant electrolyte abnormalities.16

Laboratory studies should be performed in children who are severely dehydrated and children who are receiving intravenous rehydration therapy. Serum electrolyte levels should also be obtained in children who show signs of hypernatremia or hypokalemia (Table 3), although evidence exists that these conditions, as well as hyponatremia, may resolve without complications when oral rehydration therapy is used.17

Cutaneous signs
Warm, “doughy” texture
Possibly decreased skinfold tenting in severe dehydration, thereby giving appearance of lower level of dehydration
Neurologic signs
Lethargy common, but marked irritability when touched
Ileus with abdominal distention
Cardiac arrhythmias

Studies aimed at pinpointing causative agents are usually only marginally helpful in children with domestically acquired gastroenteritis. Yet the presence of gross or occult blood in the stool should raise suspicion of such pathogens as Shigella species, Campylobacter species and hemorrhagic Escherichia coli strains. Large numbers of leukocytes on a fecal smear may also indicate an inflammatory bacterial process. In the absence of gross blood or leukocytes, costly stool cultures usually have a very low yield and rarely change clinical management because most noninflammatory diarrheas are self-limited.6,18

Similarly, viral studies, such as rotavirus antigen tests, may confirm the causative agent but do not usually change management. Giardia antigen studies and smears for ova and parasites are generally not indicated unless the diarrheal illness lasts more than 10 days or a likely exposure history exists.6,11,19

Management of Dehydration

The management of acute gastroenteritis is directed at preventing or treating the dehydration that so often accompanies this disease. Unless otherwise noted, the recommendations given in this section are from the AAP's practice parameter and are summarized in Table 4.2 These recommendations are based on two major conclusions:

  1. Oral rehydration therapy should be the initial treatment because it is as effective as intravenous therapy in rehydrating and replacing electrolytes in children with mild to moderate dehydration.

  2. An age-appropriate diet should be continued in children with diarrhea who are not dehydrated, and an age-appropriate diet should be resumed as soon as rehydration is accomplished in children with mild to moderate dehydration.

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Children who have diarrhea without vomiting and who have been determined not to be dehydrated based on the physical examination may be safely continued on an age-appropriate diet. As long as signs or symptoms of malabsorption do not develop during the treatment period, it is not necessary to withhold specific foods, including full-strength milk and other dairy products.20 Some evidence exists showing that complex carbohydrates, lean meats, yogurt, fruits and vegetables are better tolerated than fatty foods or foods with a high simple sugar content (e.g., juices and soft drinks).11 Adding an oral rehydration solution to the regular feeding routine provides no extra benefit, although the solution may be accepted by a child who refuses other foods and fluids.


Children with diarrhea and mild to moderate dehydration on clinical evaluation should be treated with one of the commercially available oral rehydration preparations. The numerous formulations available in the United States differ primarily in their sodium content and osmolality (Table 5).2,21 All contain glucose or glucose polymers as their carbohydrate. The World Health Organization oral rehydration formulation, not readily available in the United States, has the highest sodium content as well as the highest osmolality. No evidence exists to show that one formula is superior to another in effecting rehydration.16,22,23 All of the preparations are equally safe, even in children with known electrolyte abnormalities, once they are hemodynamically stable.15

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The cost of commercial oral rehydration preparations is often cited as a barrier to their use. This expense is usually not covered by insurance plans. However, cost varies widely among brands and preparations and should not preclude the use of these products (Table 6).

Premixed brand name oral rehydration solutions$4 to $6 for about 1,000 mL
House brand (generic) oral rehydration solutions (usually comparable to Pedialyte in electrolyte content)Unavailable
World Health Organization oral rehydration solution salts packets (one packet makes 1 L of solution)$0.50 per packet (sold in a carton containing 125 packets)

The time-honored “clear liquids” most often used by parents or recommended by physicians in the past are not appropriate for use in oral rehydration therapy. Drinks such as colas, ginger ale, apple juice and even commercial sports drinks (e.g., Gatorade) are inappropriately high in carbohydrates and osmolality (Table 7).11 They can cause osmotic worsening of diarrhea, and their low sodium content may contribute to the development of hyponatremia. Tea should not be used because of its low sodium content, and chicken broth is contraindicated because of its high sodium content.5,11 Furthermore, food should not be arbitrarily withheld because continued feeding or the early resumption of feeding improves outcome.24

LiquidElectrolyte content (mEq per L)
Na+ K+ HCO3Carbohydrate (g per L)Osmolality (mOsm per kg)
Cola20.11350 to 150, glucose and fructose550
Ginger ale31450 to 150, glucose and fructose540
Apple juice3200100 to 150, glucose and fructose700
Chicken broth250500450
Gatorade203345, glucose and other sugars330

Even children who are vomiting can usually be treated with oral rehydration therapy. When an oral solution is administered by the caregiver in controlled amounts (one or two teaspoons every one to two minutes, with gradual increases in amount as tolerated), the familiar regimen of “frequent small sips” can deliver a volume significant enough to achieve rehydration and maintain hydration in more than 90 percent of children with acute gastroenteritis.11,16 As long as ileus has been ruled out, an oral rehydration solution may be given through a nasogastric feeding tube in a child who is hemodynamically stable but unwilling or unable to drink adequately because of continued vomiting.25 Specific recommendations for the amount of oral rehydration solution that should be given and the schedule for its administration are summarized in Table 4.2

Occasionally, no caregiver is available to administer the labor-intensive oral rehydration therapy to a child who is moderately to severely dehydrated but hemodynamically stable. In this situation, outpatient rapid intravenous hydration followed by oral rehydration maintenance therapy may be used and may prevent the need for hospitalization.26


Intravenous therapy is usually reserved for use in children with severe dehydration, which is marked by the presence of shock or near-shock. Signs of hemodynamic instability, including profound lethargy, markedly delayed capillary refill and tachycardia with severe orthostatic blood pressure changes, represent a medical emergency and require immediate and aggressive intravenous therapy to restore intravascular volume.

Normal saline solution or Ringer's lactate should be given in a rapid intravenous bolus of 20 mL per kg. The patient is then reevaluated and, if needed, the treatment is repeated (Table 4).2 When necessary, an intraosseous line may be used in a child of suitable age (i.e., up to six years old27). If intravenous access cannot be obtained in a timely manner, administration of an oral rehydration solution through a nasogastric tube may also be considered if the child is conscious and ileus has been ruled out.

Management of Symptoms

Parents and older patients often request specific medications for the most prominent symptoms of acute gastroenteritis (vomiting and diarrhea). Although such agents are commonly prescribed, their use remains controversial. An AAP subcommittee reported a consensus opinion that because of the self-limited nature of the vomiting and its tendency to improve with the correction of dehydration, antiemetic agents are not needed in children with acute gastroenteritis.2 Physicians were therefore advised to use discretion in prescribing antiemetic agents because of the potential for adverse effects, including allergic reactions, sedation, acute dystonic reactions and other extrapyramidal symptoms.

Antidiarrheal medications include drugs that alter intestinal secretion (bismuth subsalicylate [e.g., Pepto-Bismol]) or intestinal motility (loperamide [Imodium]), adsorbents (kaolin/pectin [e.g., Kaopectate]) and preparations containing “beneficial bacteria” (Lactobacillus [e.g., yogurt]). These agents are generally not indicated in children with acute gastroenteritis because of lack of convincing evidence that they are effective and because of concerns that adverse effects may outweigh any benefits.

Diarrhea in children should not be treated with opiate-anticholinergic combinations or opiates other than loperamide because of the high potential for toxic side effects.2 Antidiarrheal medications also have the potential to worsen the course of inflammatory bacterial enteritis, leading to toxic megacolon and colonic hemorrhage.

The use of antibiotic therapy in children with acute gastroenteritis remains controversial. Although treatment may shorten the course of some diarrheal illnesses (e.g., Shigella or traveler's diarrhea), most bacterial diarrheas are self-limited and will be resolving before the causative organism is identified. Empiric therapy should be directed at the organism thought most likely to be involved.

For some bacteria, such as noninvasive Salmonella species, treatment may prolong the carrier period after the symptoms have resolved. For others, such as Campylobacter jejuni and Yersinia enterocolitica, the efficacy of antibiotics in hastening recovery is doubtful. Empiric antibiotic therapy may even lead to the development of Clostridium difficile–associated enterocolitis and a worsening of symptoms.6

Final Comment

The development of safe, effective oral rehydration solutions as an alternative to home remedies of doubtful benefit or the use of intravenous regimens has dramatically changed the management of acute gastroenteritis in young children. Nonetheless, oral rehydration therapy is still underutilized in the developed world. Family physicians have the opportunity to change this situation by becoming familiar with the guidelines for oral rehydration therapy and instructing their patients in its appropriate use. With patient education, the reduction of medication use and the application of oral rehydration therapy in their clinical practices, family physicians can reduce outpatient morbidity and lessen the inconvenience and costs associated with emergency department and inpatient treatment of acute gastroenteritis.

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