The physical examination of the patient with vomiting and/or diarrhea should focus on excluding life-threatening illnesses and determining if the diagnosis is indeed gastroenteritis. Assessment of the patient's mental status is a key aspect of the physical examination. Lethargy or irritability may indicate severe dehydration or a significant metabolic disturbance or anatomic lesion. Once the diagnosis of gastroenteritis is assured, assessment of the patient's hydration status should be performed (Table 70-3). Children with significant vomiting and diarrhea will have fluid and electrolyte deficits. Total body water loss is calculated as a percentage of body weight: 3% to 5% loss is considered mild, 5% to 10% moderate, and greater than 10% severe. The percent of dehydration is often an estimated measure, given that the patient's baseline weight may not be known. The extent of illness in the patient depends not only on the fluid deficit, but the rate at which it has occurred. Fluid losses occurring slowly are compensated by water shifting from intracellular and interstitial spaces into the intravascular space, protecting systemic perfusion. Fulminant losses from severe diarrhea are poorly compensated, especially in infants, and can result in hypovolemic shock and death. The degree of dehydration is often difficult to assess in younger infants. A variety of methods exist for estimating the extent of dehydration. Current emphasis is focused at simplifying the hydration assessment process; mild and moderate dehydration can be grouped together. Key findings indicating significant dehydration include delayed capillary refill, abnormal skin turgor, and an abnormal respiratory pattern. Other important findings include tachycardia, dry mucus membranes, and the absence of tears.9 The importance of assessing mental status cannot be overstated. Guidelines from the World Health Organization (WHO) and UNICEF for managing diarrhea in children are available on the Internet.3,4
TABLE 70-3Assessment of Dehydration ||Download (.pdf) TABLE 70-3 Assessment of Dehydration
Two of the following signs:
Two of the following signs:
Not enough signs to classify as some or severe dehydration
Most children with gastroenteritis do not require laboratory studies commonly ordered in the emergency department, as they rarely aid in the evaluation and management. When moderate or severe dehydration is present, it may be reasonable to obtain serum electrolytes; however, the patient's hydration status can usually be ascertained from the physical examination. Most patients with significant diarrhea will have low serum bicarbonate. Hypoglycemia can accompany significant dehydration or altered mental status and warrants a bedside glucose evaluation. Stool sample for culture and ova/parasites should be considered in patients with bloody diarrhea or protracted diarrhea. Fecal leukocytes found in the stool may suggest colitis and the presence of an enteroinvasive infection, but testing has poor sensitivity and cannot discern a definite etiology. Blood cultures should be obtained in those who are at risk for bacteremia: infants and children younger than 1 year, patients with sickle cell disease, and immunocompromised patients in whom salmonella is suspected. Rotavirus antigen can be detected in the stool via enzyme immunoassay and latex agglutination but has a high false-negative rate. CBC with platelet count, electrolytes, BUN, and creatinine should be evaluated if the patient has E.coli 0157 or is suspected of having hemolytic uremic syndrome.1,3,5–8
ORT is an effective treatment for the vast majority of patients with gastroenteritis-related dehydration. ORT is credited with saving millions of lives around the world. In environments where intravenous therapy is available, ORT use has been reportedly underutilized.10 The coupled transport of sodium and glucose molecules at the intestinal brush border accompanied by free water transport is the mechanism of efficacy for ORT. A variety of oral hydration solutions (ORS) are available. Recent guidelines from the WHO and UNICEF recommend reduced concentrations of sodium (65–75 mEq/L) and glucose (75 mmol/L) in ORS. The osmolarity reduction hastens the effect of hypertonicity on net fluid absorption and shortens the duration of diarrhea and need for intravenous fluids. In most cases, rehydration can be accomplished without the risk of causing hypo- or hypernatremia.11–16
Treatment for infants and children with minimal dehydration is directed at maintaining nutrition and preventing dehydration. Rehydration can be achieved by increasing fluid intake or by administering ORS at a volume of 10 mL/kg for each stool and/or 2 mL/kg for each emesis. Continued feeding or increased breastfeeding during, and increased feeding after the diarrheal episode is recommended.4 Diet should generally not be restricted. If vomiting is present, consider limiting intake to clear liquids (Pedialyte, Ricelyte, Rehydralyte, Gatorade) and bland items (toast, crackers, rice, clear soup) until the vomiting has ceased for several hours, and then gradually advancing to a normal diet.
Patients with mild-to-moderate dehydration should receive 50 to 100 mL/kg of ORS over 2 to 4 hours with ongoing losses also replaced. Nasogastric administration of ORS is safe, effective, and beneficial in patients in whom intravenous access is difficult, or in infants who have difficulty swallowing.17 Moderately dehydrated patients who require intravenous rehydration can be rehydrated over several hours in the emergency department.18
Patients in shock or with severe dehydration require intravenous therapy. An initial bolus of 20 mL/kg of 0.9 NS or lactated Ringer's is rapidly administered and can be repeated until adequate perfusion is restored. Once perfusion is restored, hydration can be continued intravenously or by instituting ORT. Intravenous therapy involves replacing the estimated volume deficit along with maintenance fluid requirements.18 Intravenous rehydration is discussed further in Section XIV, “Fluid, Electrolyte and, Acid Base Abnormalities.”
Persistent vomiting can limit or delay oral rehydration. Studies have shown that ondansetron facilitates ORT in children with persistent vomiting and decreases the need for intravenous salvage therapy. The dose for ondansetron is 0.15 mg/kg but a general guideline for infants and children is: 2 mg for 8 to 15 kg, 4 mg for 15 to 30 kg, and 6 to 8 mg for more than 30 kg.19–25 Zinc deficiency is widespread in the developing world. Numerous studies have shown that zinc supplementation reduces the severity and duration of diarrhea in children younger than 5 years and reduces the incidence of diarrhea in the proceeding 2 months. The WHO recommends zinc supplementation (10–20 mg/d for 10–14 days) in children with diarrhea.4,26 Maintaining the nutritional status of children with diarrhea is vitally important, especially in those who are malnourished. Breastfeeding and/or an age-appropriate diet should resume as soon as the patient can tolerate feeding without vomiting. Insufficient evidence exists to support withholding lactose-containing formulas in patients with acute diarrhea. Liquids containing high sugar loads, such as colas and apple juice are best avoided because they can increase the intestinal osmotic load and worsen diarrhea.3,4 Probiotics have been used in the treatment of diarrheal illness for several years, yet studies have shown only limited benefit for mild, self-resolving causes of diarrhea. Some evidence support the use of Lactobacillus GG in addition to traditional therapy for antibiotic associated C difficile diarrhea.27 Antibiotic therapy or stool culture is not indicated in the majority of cases of diarrheal illness. Patients can have bloody diarrhea derived from underlying viral illness, such as rotavirus, or a self-limiting bacterial illness such as nontyphoidal salmonella. Stool for culture should be considered in children younger than 1 year who are febrile and toxic-appearing or those with persistent bloody diarrhea. Culture and sensitivity testing will direct antibiotic therapy. (Tables 70-3 and 70-4)
TABLE 70-4Treatment of Common Gastrointestinal Infections ||Download (.pdf) TABLE 70-4 Treatment of Common Gastrointestinal Infections
Antidiarrheal agents, including pectin and kaolin, have no therapeutic benefit. Abdominal cramping can be exacerbated in children taking Diphenoxylate (Lomotil), especially in those infected with Shigella.