AUTHOR AND EDITOR INFORMATION

Section 1 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

INTRODUCTION

Section 2 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Background

Acute diarrhea is defined as the abrupt onset of abnormally high fluid content in the stool (more than the normal value of approximately 10 mL/kg/d). This situation usually implies an increased frequency of bowel movements, which can range from 4-5 to more than 20 times per day. The augmented water content in the stools is due to an imbalance in the physiology of the small and large intestinal processes involved in the absorption of ions, organic substrates, and water. A common disorder in its acute form, diarrhea has many causes and may be mild to severe. Childhood acute diarrhea is usually caused by infection; however, a number of disorders may cause this condition, including a malabsorption syndrome and various enteropathies. Acute-onset diarrhea is usually self-limited; however, an acute infection can have a protracted course. By far, the most common complication of acute diarrhea is dehydration.

Pathophysiology

Viruses directly damage the small intestinal villi, thereby decreasing intestinal surface area and unmasking ongoing fluid secretion by enteric crypts. Furthermore, rotavirus produces an enterotoxin that possibly induces secretion and contributes to the watery diarrhea. Bacteria may cause diarrhea by several different mechanisms. Invasive bacteria cause mucosal ulceration and abscess formation with a concomitant inflammatory response. Bacterial toxins may influence enteral and extraenteric cellular processes. For example, the heat-labile and heat-stable enterotoxins of Escherichia coli activate enteral adenylate cyclase and guanylate cyclase, respectively. Verotoxin, which is produced by enterohemorrhagic E coli and Shigella species, may cause systemic disorders, such as seizures and hemolytic uremic syndrome (HUS), if absorbed. Other noninvasive bacteria and protozoa adhere to the gut wall, causing inflammation.

Noninfectious causes of diarrhea include disorders of intestinal digestive and/or absorptive processes, congenital disorders and enteropathies, endocrine abnormalities, hormone-secreting tumors, pancreatic and liver dysfunction, anatomic abnormalities, inflammatory bowel disease, and irritable bowel syndrome (also called toddler's diarrhea in individuals aged 6 mo to 3 y). These noninfectious abnormalities may have other systemic signs and symptoms and should be considered if an acute-onset diarrhea fails to resolve within 14 days or if the condition recurs.

Frequency

United States

In the United States, 1 episode per child per year is estimated to occur in children younger than 5 years, with 220,000 hospital admissions (about 10% of all admissions for children in this age range) and about 400 deaths per year. Furthermore, acute diarrhea apparently causes 20% of referrals to physicians for children younger than 2 years and 10% for children younger than 3 years.

International

In developing countries, an average of 3 episodes per child per year in children younger than 5 years has been reported, but some areas have been reported to have 6-8 episodes per child per year. In these settings, malnutrition plays an additional and important negative role by exposing children to a higher risk of acute and prolonged diarrhea.

Mortality/Morbidity

Despite important progress made in the past decade, worldwide mortality remains high, with approximately 2 million deaths per year, according to a World Health Organization (WHO) estimate.

• Diarrhea is so common that individuals outside of clinical practice may disregard potential mortality and morbidity.
• As mentioned, about 2 million children worldwide (almost entirely from developing countries) are estimated to die each year because of diarrheal illness, making the condition the second most common cause of death in children, after respiratory infections.

Sex

• Most cases of infectious diarrhea are not sex specific.
• Females have a higher incidence of Campylobacter species infections and HUS.
• Among conditions associated with chronic diarrhea, celiac disease is slightly more common in females.

Age

• Viral diarrhea is most common in young children. Rotavirus and adenovirus are particularly prevalent in children younger than 2 years. Astrovirus and calicivirus usually infect children younger than 5 years.
• Yersinia enterocolitis typically infects children younger than 1 year, and the Aeromonas organism is a significant cause of diarrhea in young children.
• Very young children are particularly susceptible to secondary dehydration and secondary nutrient malabsorption.

CLINICAL

Section 3 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

History

• Diarrhea generally implies an increase in stool volume and diminished stool consistency.
• • In children younger than 2 years, diarrhea is defined as daily stools with a mass greater than 10 mL/kg.
  • In children older than 2 years, diarrhea is defined as daily stools with a mass greater than 200 g. In practice, this typically means loose-to-watery stools passed 4 or more times per day.
  • Individual stool patterns vary widely; for example, breastfed children normally may have 5-6 stools per day.
• Abnormally watery stools may be the only symptom in some individuals with diarrhea.
• Flatulence associated with foul-smelling stools that float suggests fat malabsorption, which can be observed with infection with Giardia lamblia.
• Knowledge of the characteristics of consistency, color, volume, and frequency can be helpful in determining whether the source is from the small or large bowel. Table 1 outlines these characteristics and demonstrates that an index of suspicion can be easily generated for a specific set of organisms. 

Table 1. Stool Characteristics and Determining Their Source

Stool Characteristics	Small Bowel	Large Bowel
Appearance	Watery	Mucoid and/or bloody
Volume	Large	Small
Frequency	Increased	Highly increased
Blood	Possibly positive but never gross blood	Commonly grossly bloody
pH	Possibly <5.5	>5.5
Reducing substances	Possibly positive	Negative
WBCs	<5/high power field	Commonly >10/high power field
Serum WBCs	Normal	Possible leukocytosis, bandemia
Organisms	Viral Rotavirus Adenovirus Calicivirus Astrovirus Norwalk virus	Invasive bacteria E Coli (enteroinvasive, enterohemorrhagic) Shigella species Salmonella species Campylobacter species Yersinia species Aeromonas species Plesiomonas species
	Enterotoxigenic bacteria E coli Clostridium perfringens Cholera species Vibrio species	Toxic bacteria Clostridium difficile
	Parasites Giardia species Cryptosporidium species	Parasites Entamoeba organisms

• Associated systemic symptoms include the following:
• • Some enteric infections commonly have systemic symptoms, whereas others less commonly are associated with systemic features.
  • Table 2 outlines the frequency of some of these symptoms with particular organisms.
• Onset and duration is as follows:
• • A history of contact with unhealthy individuals, particular food exposures, or travel history may suggest a causative organism.
  • Table 2 outlines incubation periods and usual duration of symptoms of common organisms. Certain organisms (eg, C difficile, Giardia, Entamoeba species) may be associated with a protracted course.

Table 2. Organisms and Frequency of Symptoms

Organism	Incubation	Duration	Vomiting	Fever	Abdominal Pain
Rotavirus	1-7 days	4-8 days	Yes	Low	No
Adenovirus	8-10 days	5-12 days	Delayed	Low	No
Norwalk virus	1-2 days	2 days	Yes	No	No
Astrovirus	1-2 days	4-8 days	+/-	+/-	No
Calicivirus	1-4 days	4-8 days	Yes	+/-	No
Aeromonas species	None	0-2 weeks	+/-	+/-	No
Campylobacter species	2-4 days	5-7 days	No	Yes	Yes
C difficile	Variable	Variable	No	Few	Few
C perfringens	Minimal	1 day	Mild	No	Yes
Enterohemorrhagic E coli	1-8 days	3-6 days	No	+/-	Yes
Enterotoxigenic E coli	1-3 days	3-5 days	Yes	Low	Yes
Plesiomonas species	None	0-2 weeks	+/-	+/-	+/-
Salmonella species	0-3 days	2-7 days	Yes	Yes	Yes
Shigella species	0-2 days	2-5 days	No	High	Yes
Vibrio species	0-1 day	5-7 days	Yes	No	Yes
Yersinia enterocolitica	None	1-46 days	Yes	Yes	Yes
Giardia species	2 weeks	1+ weeks	No	No	Yes
Cryptosporidium species	5-21 days	Months	No	Low	Yes
Entamoeba species	5-7 days	1-2+ weeks	No	Yes	No

• Daycare considerations are as follows:
• • Certain organisms are spread quickly in daycare.
  • These organisms include rotavirus, Astrovirus, Calicivirus, and Campylobacter, Shigella, Giardia, and Cryptosporidium species.
  • Increase in daycare usage has raised the incidence of rotavirus and Cryptosporidium species.
• Food history can be helpful.
• • Ingestion of raw or contaminated food is a common cause.
  • Table 3 outlines organisms that cause food poisoning.

  Table 3. Organisms That Cause Food Poisoning

  Food History	Organism
  Dairy	Campylobacter and Salmonella species
  Eggs	Salmonella species
  Meats	C perfringens, Aeromonas, Campylobacter, and Salmonella species
  Ground beef	Enterohemorrhagic E coli
  Poultry	Campylobacter species
  Pork	C perfringens, Y enterocolitica
  Seafood	Astrovirus, Aeromonas, Plesiomonas, and Vibrio species
  Oysters	Calicivirus, Plesiomonas and Vibrio species
  Vegetables	Aeromonas species, C perfringens

• Water exposure can contribute to diarrhea.
• • Water is a major reservoir for many organisms that cause diarrhea.
  • Swimming pools have been associated with outbreaks of infection with Shigella species; Aeromonas organisms are associated with exposure to the marine environment.
  • Giardia, Cryptosporidium, and Entamoeba organisms are resistant to water chlorination; therefore, exposure to contaminated water should raise index of suspicion for these parasites.
• A history of camping suggests exposure to water sources contaminated with Giardia organisms.
• Travel history may indicate a cause for diarrhea.
• • Enterotoxigenic E coli is the leading cause of traveler's diarrhea.
  • Rotavirus and Shigella, Salmonella, and Campylobacter organisms are prevalent worldwide and need to be considered regardless of specific travel history.
  • Other organisms that are prevalent in particular parts of the world are listed in Table 4.
  • Risk of contracting diarrhea while traveling is, by far, highest for persons traveling to Africa.
  • Travel to Central and South America and Eastern European countries is also associated with a relatively high risk of contracting diarrhea.

Table 4. Organisms Associated With Travel

Foreign Travel History	Organism
Nonspecific	Enterotoxigenic E coli, Aeromonas, Giardia, Plesiomonas, Salmonella, and Shigella species
Underdeveloped tropics	C perfringens
Africa	Entamoeba species, Vibrio cholerae
South and Central America	Entamoeba species, V cholerae, enterotoxigenic E coli
Asia	V cholerae
Australia	Yersinia species
Canada	Yersinia species
Europe	Yersinia species
India	Entamoeba species, V cholerae
Japan	Vibrio parahaemolyticus
Mexico	Aeromonas, Entamoeba, Plesiomonas, and Yersinia species
New Guinea	Clostridium species

Table 5. Medical Conditions That Predispose Individuals to Diarrhea

Organism	Comorbid Risk Factors
C difficile	Hospitalization, antibiotic administration
Plesiomonas species	Liver diseases or malignancy
Salmonella species	Intestinal dysmotility, malnutrition, achlorhydria, hemolytic anemia (especially sickle cell disease), immunosuppression, malaria
Rotavirus	Hospitalization
Giardia species	Agammaglobulinemia, chronic pancreatitis, achlorhydria, cystic fibrosis
Cryptosporidia species	Immunocompromised or immunosuppressed state

Physical

• Dehydration
• • Dehydration is the principal cause of morbidity and mortality.
  • Assess every patient with diarrhea for signs, symptoms, and severity.
  • Lethargy, depressed consciousness, sunken anterior fontanel, dry mucous membranes, sunken eyes, lack of tears, poor skin turgor, and delayed capillary refill are obvious and important signs of dehydration.
• Failure to thrive and malnutrition
• • Reduced muscle and fat mass or peripheral edema may be clues to the presence of carbohydrate, fat, and/or protein malabsorption.
  • Giardia organisms can cause intermittent diarrhea and fat malabsorption.
• Abdominal pain
• • Nonspecific nonfocal abdominal pain and cramping are common with some organisms.
  • Pain usually does not increase with palpation.
  • With focal abdominal pain worsened by palpation, rebound tenderness, or guarding, be alert for possible complications or for another noninfectious diagnosis.
• Borborygmi: Significant increases in peristaltic activity can cause an audible and/or palpable increase in bowel activity.
• Perianal erythema
• • Frequent stools can cause perianal skin breakdown, particularly in young children.
  • Secondary carbohydrate malabsorption often results in acidic stools.
  • Secondary bile acid malabsorption can result in a severe diaper dermatitis that is often characterized as a "burn."

Causes

• Viruses
• • Rotavirus is by far the single most common cause of infectious diarrhea worldwide.
    • Rotavirus infection accounts for 33% of hospitalizations and 20% of deaths associated with infectious gastroenteritis.
    • Rotavirus is prevalent throughout the year; however, peak incidence occurs in the winter months.
  • Adenovirus is the second most common cause of viral gastroenteritis in hospitalized children.
• Bacteria
• • Salmonella, Shigella, and Campylobacter organisms are the 3 most common causes of bacterial diarrhea in children worldwide, with Aeromonas organisms a close fourth.
  • Infections with Aeromonas and Shigella organisms are most common during the summer and fall seasons.
  • Infections with Campylobacter organisms typically occur during the summer months.
  • Infections with Yersinia organisms occur most often during the winter months, particularly in colder climates.

DIFFERENTIALS

Section 4 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

WORKUP

Section 5 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Lab Studies

• A stool pH level of 5.5 or less or presence of reducing substances indicates carbohydrate intolerance, which is usually secondary to viral illness and transient in nature.
• Enteroinvasive infections of the large bowel cause leukocytes, predominantly neutrophils, to be shed into stool. Absence of fecal leukocytes does not eliminate the possibility of enteroinvasive organisms. However, presence of fecal leukocytes eliminates consideration of enterotoxigenic E coli, Vibrio species and viruses.
• Examine any exudates found in stool for leukocytes. Such exudates highly suggest colitis (80% positive predictive value). Colitis can be infectious, allergic, or part of inflammatory bowel disease (Crohn disease, ulcerative colitis).
• Many different culture mediums are used to isolate bacteria (see Table 7). Table 6 lists common bacteria and optimum culture mediums for their growth. A high index of suspicion is needed to choose the appropriate medium.
• With stool not cultured within 2 hours of collection, refrigerate at 4°C or place in a transport medium. Although stool cultures are useful when positive, yield is low.
• Always culture stool for Salmonella, Shigella, and Campylobacter organisms and Y enterocolitica in the presence of clinical signs of colitis or if fecal leucocytes are found.
• Look for C difficile in persons with episodes of diarrhea characterized by colitis and/or blood in the stools. Remember that acute-onset diarrheal episodes associated with C difficile may also occur without a history of antibiotic use.
• Bloody diarrhea with a history of ground beef ingestion must raise suspicion for enterohemorrhagic E coli. If E coli is found in the stool, determine if the type of E coli is O157:H7. This type of E coli is the most common, but not only, cause of HUS.
• History of raw seafood ingestion or foreign travel should prompt additional screening for Vibrio and Plesiomonas species. 

Table 6. Common Bacteria and Optimum Culture Mediums

Organism	Detection Method	Microbiologic Characteristics
Aeromonas species	Blood agar	Oxidase-positive flagellated gram-negative bacillus (GNB)
Campylobacter species	Skirrow agar	Rapidly motile curved gram-negative rod (GNR); Campylobacter jejuni 90% and Campylobacter coli 5% of infections
C difficile	Cycloserine-cefoxitin-fructose-egg (CCFE) agar; enzyme immunoassay (EIA) for toxin; latex agglutination (LA) for protein	Anaerobic spore-forming gram-positive rod (GPR); toxin-mediated diarrhea; produces pseudomembranous colitis
C perfringens	None available	Anaerobic spore-forming GPR; toxin-mediated diarrhea
E coli	MacConkey eosin-methylene blue (EMB) or Sorbitol-MacConkey (SM) agar	Lactose-producing GNR
Plesiomonas species	Blood agar	Oxidase-positive GNR
Salmonella species	Blood, MacConkey EMB, xylose-lysine-deoxycholate (XLD), or Hektoen enteric (HE) agar	Nonlactose non–H2S-producing GNR
Shigella species	Blood, MacConkey EMB, XLD, or HE agar	Nonlactose and H2S-producing GNR; verotoxin (neurotoxin)
Vibrio species	Blood or thiosulfate-citrate-bile-salts-sucrose (TCBS) agar	Oxidase-positive motile curved GNB
Y enterocolitica	Cefsulodin-ingrasan-novobiocin (CIN) agar	Nonlactose-producing oval GNR

Table 7. Culture Mediums Used to Isolate Bacteria

Blood agar	All aerobic bacteria and yeast; detects cytochrome oxidase production
MacConkey eosin-methylene blue (EMB) agar	Inhibits gram-positive organisms; permits lactose fermentation
Xylose-lysine-deoxycholate (XLD) agar; Hektoen enteric (HE) agar	Inhibits gram-positive organisms and nonpathogenic GNB; permits lactose fermentation and H2S production
Skirrow agar	Selective for Campylobacter species
Sorbitol-MacConkey (SM) agar	Selective for enterohemorrhagic E coli
Cefsulodin-ingrasan-novobiocin (CIN) agar	Selective for Y enterocolitica
Thiosulfate-citrate-bile-sucrose (TCBS) agar	Selective for Vibrio species
Cycloserine-cefoxitin-fructose-egg (CCFE) agar	Selective for C difficile

• Rotavirus antigen can be identified by enzyme immunoassay and latex agglutination assay of the stool. The false-negative rate is approximately 50%, and false-positive results occur, particularly in the presence of blood in the stools.
• Adenovirus antigens can be detected by enzyme immunoassay. Only serotypes 40 and 41 are able to induce diarrhea.
• Examination of stools for ova and parasites is best for finding parasites. Perform stool examination every 3 days or every other day.
• The leukocyte count is usually not elevated in viral-mediated and toxin-mediated diarrhea. Leukocytosis is often but not constantly observed with enteroinvasive bacteria. Shigella organisms cause a marked bandemia with a variable total white blood cell count.
• At times, a protein-losing enteropathy can be found in patients with extensive inflammation in the course of enteroinvasive intestinal infections (eg, Salmonella species, enteroinvasive E coli). In these circumstances, low serum albumin levels and high fecal alpha1-antitrypsin levels can be found.

Procedures

• Intestinal biopsy: This procedure may be indicated in the presence of chronic or protracted diarrhea, as well as in cases in which a search for a cause is believed to be mandatory (eg, in patients with acquired immunodeficiency syndrome [AIDS] or patients who are otherwise severely immunocompromised).

TREATMENT

Section 6 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Medical Care

Because most infectious diarrhea is self-limiting, medical care is primarily supportive and aimed at maintaining hydration, treating dehydration, or both. Oral rehydration therapy (ORT) is the mainstay of treatment in all children with diarrhea; never neglect ORT, even in the absence of overt dehydration because maintaining hydration is necessary. Neonates and young infants are at high risk of secondary complications and require close monitoring. Consider intravenous rehydration only in the unlikely event that ORT is unsuccessful.

• ORT is the cornerstone of treatment, especially for small-bowel infections that produce a large volume of watery stool output.
• • Not all commercial ORT formulas promote optimal absorption of electrolytes, water, and nutrients.
  • The ideal solution has a low osmolarity (210-250) and a sodium content of 50-60 mmol/L.
  • Administer maintenance fluids plus replacement of losses. Educate caregivers in methods necessary to replace this amount of fluid.
  • Administer small amounts of fluid at frequent intervals to minimize discomfort and vomiting.
  • A 5-cc or 10-cc syringe without a needle is a very useful tool. The syringe can be used to quickly place small amounts of fluid in the mouth of a child who is uncooperative.
  • Once the child becomes better hydrated, cooperation improves enough to take small sips from a cup. This method is time intensive and requires a dedicated caregiver.
  • Encouragement from the physician is necessary to promote compliance.
  • OR is now universally recommended to be completed in an expedite way, within 4 hours.
• At completion of hydration, resumption of feeding is recommended strongly. In fact, many studies convincingly demonstrate that early refeeding hastens recovery. Also, robust evidence suggests that, in the vast majority of episodes of acute diarrhea, refeeding can be accomplished without the use of any special (eg, lactose-free or soy-based) formulas.
• Antimotility agents are not indicated for infectious diarrhea, except for refractory cases of Cryptosporidium infection.
• Antimicrobial therapy is indicated for some nonviral diarrhea, since most is self-limiting and does not require therapy. Table 8 lists standard therapies. 

Table 8. Therapies for Nonviral Diarrhea

Aeromonas species	Use cefixime and most third- and fourth-generation cephalosporins.
Campylobacter species	Erythromycin shortens illness duration and shedding.
C difficile	Discontinue potential causative antibiotics. If antibiotics cannot be stopped or this does not result in resolution, use oral metronidazole or vancomycin. Vancomycin is reserved for the child who is seriously ill.
C perfringens	Do not treat with antibiotics.
Cryptosporidium parvum	Paromomycin; however, effectiveness is not proven. Nitazoxanide, a newer anthelmintic, is effective against C parvum.
Entamoeba histolytica	Metronidazole followed by iodoquinol or paromomycin Asymptomatic carriers in nonendemic areas: Iodoquinol or paromomycin
E coli	Trimethoprim-sulfamethoxazole (TMP-SMX) if moderate or severe; antibiotic treatment may increase likelihood of HUS. Parenteral second-generation or third-generation cephalosporin for systemic complications
G lamblia	Metronidazole or nitazoxanide can be used.
Plesiomonas species	Use TMP-SMX or any cephalosporin.
Salmonella species	Treatment prolongs carrier state, is associated with relapse, and is not indicated for nontyphoid-uncomplicated diarrhea. Treat infants younger than 3 months and high-risk patients (eg, immunocompromised, sickle cell disease). TMP-SMX is first-line medication; however, resistance occurs. Use ceftriaxone and cefotaxime for invasive disease.
Shigella species	Treatment shortens illness duration and shedding but does not prevent complications. TMP-SMX is first-line medication; however, resistance occurs. Cefixime, ceftriaxone, and cefotaxime are recommended for invasive disease.
V cholerae	Treat infected individuals and contacts. Doxycycline is the first-line antibiotic, and erythromycin is second-line antibiotic.
Yersinia species	TMP-SMX, cefixime, ceftriaxone, and cefotaxime are used. Treatment does not shorten disease duration; reserve for complicated cases.

Consultations

• Surgeon
• • Certain organisms cause abdominal pain and bloody stools.
  • Symptoms resembling appendicitis, hemorrhagic colitis, intussusception, or toxic megacolon may be appreciated.
  • If the infectious etiology in individuals with such symptoms is not certain, seek consultation with a surgeon.
• Infectious-disease specialist: Consider consultation with an infectious-disease specialist for any patient who is immunocompromised because of HIV infection, chemotherapy, or immunosuppressive drugs, since atypical organisms are more likely, and complications can be more serious and fulminate.

Diet

• Bananas, rice, applesauce, and toast diet
• • A banana, rice, applesauce, and toast (BRAT) diet has been recommended for years.
  • However, no evidence shows that this diet is useful, and its poor protein content may be a contraindication; therefore, do not recommend a BRAT diet.
  • A strong body of evidence now suggests that resuming the prediarrhea diet is perfectly safe and must be encouraged, obviously respecting any (usually temporary) lack of appetite.
• Lactose ingestion
• • Although rotavirus can cause secondary transient lactose intolerance, this finding is believed to be generally not clinically relevant; use lactose-containing formulas in all individuals with diarrhea.
  • In an incident of worsening of diarrhea proven to be secondary to a clinically important lactose malabsorption in infants positive for rotavirus, a very transient use of lactose-free formulas (5-6 d) can be considered.
• Breastfeeding
  • Breast milk contains many substances that promote bowel growth and antagonize bacteria.
  • Strong evidence in the literature demonstrates that the continued use of breast milk is actually beneficial in children with acute diarrhea.
  • Thus, encourage that breastfeeding continue throughout illness, providing additional OR solution while diarrheal output persists.

MEDICATION

Section 7 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Diarrheal diseases have been the object of numerous forms of treatment, both dietetic and pharmacologic, for centuries. However, the evidence is now clear that, in most cases, the best option for treatment of acute-onset diarrhea is the early use of ORT. Pharmacological treatment is rarely of any use, and drugs are often harmful.

Drug Category: Antibiotic and antiparasitics agents

Antimicrobial agents, in addition to the immune system, help destroy offending organisms. Their use is confined to specific etiologies and/or clinical circumstances.

Drug Category: Vaccines

These agents elicit active immunization to increase resistance to infection. Vaccines consist of microorganisms or cellular components, which act as antigens. Administration of the vaccine stimulates the production of antibodies with specific protective properties.

FOLLOW-UP

Section 8 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Further Inpatient Care

• Admit neonates or young infants with moderate dehydration, suspected infection with enterohemorrhagic E coli, or bloody diarrhea.
• ORT is the universally recommended form of treatment, proven to be successful even in children who vomit or have mild-to-moderate dehydration. Admit a child with severe dehydration. Also, ORT requires vigilance. If the caregiver cannot comply with protocol, consider admission.

Further Outpatient Care

• Follow-up care depends on the severity of diarrhea and the child's age.
• Uncomplicated diarrhea in a school-aged child may not require follow-up care if the caregiver is reliable and has quick access to a physician.
• Closely monitor young children to ensure that complications do not occur.
• Closely monitor children who require labor-intensive ORT.
• Neonates require strict follow-up care within a few days of illness to ensure that malabsorption and dehydration do not occur.

Deterrence/Prevention

• Vaccination
• • Vaccines are indicated for persons with high risk of exposure to some pathogens.
  • In February 2006, the United States Food and Drug Administration (FDA) approved an oral vaccine for rotavirus (RotaTeq). It is currently the only vaccine approved in the United States for prevention of rotavirus gastroenteritis as of the date of this publication. On February 21, 2006, the American Academy of Pediatrics (AAP) and the Advisory Committee on Immunization Practices (ACIP) recommended RotaTeq to be part of regularly scheduled childhood immunizations. RotaTeq is administered in a 3-dose series starting between age 6-12 weeks and completing before 32 weeks. An older rotavirus vaccine (RotaShield) was associated with an increased incidence of intussusception and is no longer on the market, but RotaTeq did not show an increased risk compared with placebo in clinical trials.
  • In April 2008, the FDA approved Rotarix, another oral vaccine, for prevention of rotavirus gastroenteritis. The current recommendation is to administer 2 separate doses of Rotarix to patients aged 6-24 weeks. Rotarix was efficacious in a large study, which reported that Rotarix protected patients with severe rotavirus gastroenteritis and decreased the rate of severe diarrhea or gastroenteritis of any cause.¹⁰
  • A study that involved over 63,000 patients who received Rotarix or placebo at age 2 months and at age 4 months reported a decreased risk of intussusception in patients who received Rotarix.¹⁰ The intussusception data was determined over a 31-day observation period (inpatient or outpatient) after each dose of the Rotarix vaccine; this also included a 100-day surveillance period for all serious adverse events.  Although more patients who received Rotarix were observed to have seizures or pneumonia-related deaths, this link has not been directly established to Rotarix. In addition, the FDA is requiring the Rotarix manufacturer to report data on postmarketing safety in a study that involves over 40,000 patients.
  • The Salmonella typhi vaccine is recommended for travelers to countries with a high risk of this infection, persons with intimate exposure to a documented typhoid fever carrier, and workers with frequent exposure to this bacteria. Live-attenuated, killed whole-cell, and capsular polysaccharide vaccines are available.
  • The Vibrio species vaccine is available but only protects 50% of immunized persons for 3-6 months. It is not indicated for use.

Complications

• Table 9 outlines common complications that can occur with various organisms.

  Table 9. Common Complications

  Organism	Complications
  Aeromonas caviae	Intussusception, gram-negative sepsis, HUS
  Campylobacter species	Bacteremia, meningitis, cholecystitis, urinary tract infection, pancreatitis, Reiter syndrome (RS)
  C difficile	Chronic diarrhea
  C perfringens serotype C	Enteritis necroticans
  Enterohemorrhagic E coli	Hemorrhagic colitis
  Enterohemorrhagic E coli O157:H7	HUS
  Plesiomonas species	Septicemia
  Salmonella species	Enteric fever, bacteremia, meningitis, osteomyelitis, myocarditis, RS
  Shigella species	Seizures, HUS, perforation, RS
  Vibrio species	Rapid dehydration
  Yersinia enterocolitica	Appendicitis, perforation, intussusception, peritonitis, toxic megacolon, cholangitis, bacteremia, RS
  Rotavirus	Isotonic dehydration, carbohydrate intolerance
  Giardia species	Chronic fat malabsorption
  Cryptosporidium species	Chronic diarrhea
  Entamoeba species	Colonic perforation, liver abscess

• Enteric fever is caused by S typhi. This syndrome has an insidious onset of malaise, fever, abdominal pain, and bradycardia. Diarrhea and rash (rose spots) appear after 1 week of symptoms. Bacteria may have disseminated at that time, and treatment is required to prevent systemic complications such as hepatitis, myocarditis, cholecystitis, or GI bleeding.

• HUS is caused by damage to vascular endothelial cells by verotoxin (released by enterohemorrhagic E coli and by Shigella organisms). Thrombocytopenia, microangiopathic hemolytic anemia, and acute renal failure characterize HUS. Symptoms usually develop 1 week after onset of diarrhea, when the organism may be absent.

• RS can complicate acute infections and is characterized by arthritis, urethritis, conjunctivitis, and mucocutaneous lesions. Individuals with RS usually do not demonstrate all features.

• Carrier states are observed after some bacterial infections.

• • After diarrhea caused by Salmonella organisms, 1-4% of individuals with nontyphoid and enteric fever infections become carriers. The carrier stage for Salmonella organisms is more likely for females, infants, and individuals with biliary tract disease.
  • Asymptomatic C difficile carriage may be observed in as many as 20% of hospitalized patients receiving antibiotics and in 50% of infants.
  • Rotavirus is excreted asymptomatically in feces of children who were previously infected, typically for up to 1-2 weeks.

Prognosis

• In developed countries, with proper management, prognosis is very good.
• Death is caused predominantly by dehydration and secondary malnutrition from a protracted course. Severe dehydration must be managed with parenteral fluids. Once malnutrition from secondary malabsorption begins, prognosis turns grim unless the patient is hospitalized and supplemental parenteral nutrition is started. Neonates and young infants are at particular risk of dehydration, malnutrition, and malabsorption syndromes.
• Even though the mortality rate is low in developed countries, children can die from complications; however, prognosis for children in countries without modern medical care and children with comorbid conditions is more guarded.

Patient Education

• Education is most important for prevention and treatment.
• Proper ORT prevents dehydration, and early refeeding speeds recovery of intestinal mucosa.
• With caregiver, emphasize proper hygiene and food preparation practices to prevent future infections and spread.
• For excellent patient education resources, visit eMedicine's Esophagus, Stomach, and Intestine Center. Also, see eMedicine's patient education articles Irritable Bowel Syndrome, Inflammatory Bowel Disease, and Diarrhea.

REFERENCES

Section 9 of 9

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

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