Gastroenteritis in Children

9 Interesting Facts of Gastroenteritis in Children 

1. Acute gastroenteritis is an infection of the gastrointestinal tract by a viral, bacterial, or parasitic pathogen resulting in inflammation causing 3 or more episodes of diarrhea and/or vomiting possibly accompanied by other symptoms
2. Acute gastroenteritis lasts up to 14 days with symptoms including fever, crampy abdominal pain, nausea, vomiting, and diarrhea ¹
3. When acute gastroenteritis symptoms are present, include an estimate of degree of dehydration and focus on excluding differential diagnoses using history and physical examination
4. Laboratory testing of electrolytes and point of care glucose testing are indicated only in certain scenarios
5. Laboratory testing to identify a specific pathogen is rarely indicated or beneficial to clinical decision making in the acute setting unless the patient presents with persistent high fever, bloody diarrhea, immunocompromised state, or significant underlying medical comorbidity ¹
6. Most cases of acute diarrhea are self-limited in children, and treatment is focused on maintaining hydration status and treating symptoms of fever and vomiting
7. Other recommended adjuncts to acute gastroenteritis treatment in children include probiotics, early refeeding, and use of ondansetron to facilitate effective oral rehydration therapy in patients with vomiting
8. Directed antibiotic use is recommended if based on positive culture results for certain offending bacterial pathogens in certain clinical situations
9. Hemolytic uremic syndrome is the most concerning complication in children who suffer from bacterial acute gastroenteritis in the developed world

Pitfalls

• Do not dismiss vomiting as sole symptom of early gastroenteritis in children. Differential diagnosis for vomiting in children of different age groups is wide
• Urinary tract infection can present with symptoms similar to acute gastroenteritis in a young child
• Presence of diarrhea does not exclude diagnosis of appendicitis, intussusception, or other surgical conditions
• Avoid unnecessary laboratory testing in children with mild to moderate dehydration secondary to acute gastroenteritis
• Avoid empiric antibiotics for suspected bacterial gastroenteritis in otherwise healthy hosts until results of bacterial stool culture are available, unless specifically indicated
  • Antibiotics are contraindicated with enterohemorrhagic Escherichia coli infection owing to increased risk of hemolytic uremic syndrome associated with antibiotic use ²
• Avoid use of antimotility agents in children with acute gastroenteritis

Terminology

Clinical Clarification

• Acute gastroenteritis is an infection of the gastrointestinal tract caused by a viral, bacterial, or parasitic pathogen resulting in inflammation causing 3 or more episodes of diarrhea and/or vomiting possibly accompanied by other symptoms (eg, fever, nausea, abdominal pain) ^3 1

Classification

• By symptom duration: ¹
  • Acute gastroenteritis
    • Symptoms last less than 14 days ¹
  • Persistent gastroenteritis
    • Symptoms last 14 to 30 days ¹
  • Chronic gastroenteritis
    • Symptoms last more than 30 days ¹
• By pathogenesis: ¹
  • Bacterial (noninflammatory)
    • Foodborne illness caused by preformed toxins
    • Food- or waterborne illness caused by organisms that form toxins after ingestion
  • Bacterial (inflammatory)
    • Invasive infections transmitted by food, water, or direct contact; some are toxin producing in addition to having other invasive mechanisms
  • Bacterial (antibiotic-associated)
    • May be due to nonspecific alteration of microbial balance or a specific pathogen (eg, Clostridioides difficile)
  • Viral
    • Common in all age groups but particularly very young children
  • Parasitic
    • Parasitic infections are the infectious cause most often identified in chronic gastroenteritis
• By clinical or epidemiologic features: ¹
  • Traveler’s diarrhea
    • Diarrhea that usually begins within 5 to 15 days of arrival in a developing country is usually associated with sudden onset of watery diarrhea ⁴
  • Dysentery
    • Invasive diarrhea associated with blood and mucous in the stool, often associated with fever and significant abdominal pain ⁵

Diagnosis

Clinical Presentation

History

• Course of illness varies by specific cause of acute gastroenteritis and by patient
  • Depending on the specific pathogen and host, fever may be present in the first few days of illness
    • Persistent fever for more than a few days can be consistent with acute gastroenteritis but may suggest an alternative diagnosis
  • Either vomiting or diarrhea may predominate
    • In patients who experience both vomiting and diarrhea, vomiting tends to precede development of diarrhea
    • Vomiting usually starts after onset of fever or abdominal pain ⁶
      • In patients with bilious emesis and hematemesis without diarrhea, strongly consider alternative diagnosis ³
      • Vomiting for more than 24 to 48 hours without associated diarrhea is extremely unlikely to represent acute gastroenteritis ⁷
    • Diarrhea is defined as increased frequency (more than 3 episodes in 24 hours) of loose or watery stools ⁸
      • Stools are described as watery, loose, bloody, or mucoid in nature
        • Stool quantity and frequency can vary from a few small loose stools per day to 10, 20, or more voluminous stools per day associated with stool incontinence ¹
        • Associated tenesmus occasionally is reported
        • Dysentery is a syndrome of prolonged (weeks to months) gastrointestinal symptoms progressing from an initial phase of watery diarrhea to passage of smaller-volume stools containing blood, mucus, or pus. Dysentery is associated with fever, lower abdominal pain, and tenesmus ²
          • Suggests infection due to inflammatory bacteria or amoebae
  • Abdominal pain is common
    • Cramping abdominal pain is a characteristic symptom of acute gastroenteritis; occasionally severe, intermittent, or vague periumbilical pain is reported
    • Pain is typically worse before patient has a bowel movement or a bout of emesis
    • Consider alternative diagnosis with presence of severe abdominal pain, especially pain that is worse with movement ³
• Symptoms that may indicate need for aggressive management include: ⁹
  • Bilious or bloody vomiting
  • Altered level of consciousness
  • Inconsolable crying or excessive irritability
  • Rapid breathing
  • High fever (40 °C or higher)
  • Petechial rash
• Symptoms suggestive of dehydration include limited oral intake, dry mouth, thirst, decreased urine output, acute weight loss, and absence of tears
• Dietary history before symptom onset may reveal potential source for infection (eg, bacterial pathogens from raw eggs, unpasteurized dairy products, undercooked meat)
• May have history of exposure to other potential acute gastroenteritis sources, including:
  • Residence in long-term care or nursing facility (bacterial pathogens, including Clostridioides difficile)
  • Attending day care (bacterial and viral pathogens, giardia)
  • Possible contaminated water source, including streams, lakes, or swimming pools (Giardia, Cryptosporidium)
  • Contact with ill people who have similar symptoms (bacterial or viral pathogens)
  • Recent history of travel to developing countries (bacterial, viral, or parasitic pathogens)
  • Contact with animals (bacterial pathogens, cryptosporidia)

Physical examination

• Vital signs
  • Tachycardia and increased respiratory rate may be present in mild to moderately dehydrated children
  • Fever may or may not be present
  • Hypotension suggests decompensated shock, an ominous sign in children
• General appearance and mobility
  • Lethargy, listlessness, and profoundly ill appearance are signs of significant dehydration, bacterial enteritis, or sepsis
    • A child who appears happy, active, and energetic (despite amount of stool output reported) does not have clinically significant dehydration
  • Depressed mental status is a sign of poor end-organ perfusion, dehydration, and shock
  • Guarding movements on stretcher suggest intra-abdominal surgical pathology
  • Jerking movements raise suspicion for hypernatremic dehydration
  • Normal gait suggests absence of intra-abdominal surgical pathology
  • Ability to lie down and stand upright without a syncopal or presyncopal spell precludes orthostasis
• Hydration assessment
  • Clinical dehydration scales are useful to define severity of dehydration
    • Various scales have been developed; parameters assessed may include weight, appearance, eyes, mucous membranes, and tears ⁹
  • Signs of dehydration include:
    • Delayed central capillary refill (longer than 2-3 seconds) ¹⁰
    • Sunken appearance of eyes, reduced periorbital fat
    • Dry mucous membranes
    • Decreased skin turgor
    • Acute weight loss
    • Cool extremities
    • Tachycardia, tachypnea
  • Signs of clinical shock include:
    • Profoundly ill appearance with depressed mental status or lethargy, pallor, and cold extremities
    • Tachycardia with weak peripheral pulses
    • Hypotension
    • Absent peripheral pulses
• Abdominal examination
  • Abdomen may be minimally and diffusely tender, but focal tenderness is absent
    • Patient is able to move easily on stretcher without peritoneal signs
    • No signs of organomegaly
    • Typically no abdominal distention is encountered
  • Bowel sounds may be normal or hyperactive with acute gastroenteritis
• Physical findings that indicate need for prompt aggressive treatment include: ⁹
  • Altered mental status
  • Cyanosis
  • Petechial rash
  • Poor peripheral perfusion
  • Rapid respiratory rate
  • Fever of 40 °C or higher
  • Age younger than 6 months or low body weight

Causes and Risk Factors

Causes

• Viral (50%-70%) ¹
  • Symptom onset with viral acute gastroenteritis typically occurs after a 1- to 2-day incubation period; illness lasts 4 to 7 days in an otherwise healthy child ¹¹
  • Closed communities are often affected (eg, institutions, day care centers, hospitals, cruise ships)
  • Rotavirus (Related: Rotavirus Infection)
    • Responsible for severe dehydrating acute gastroenteritis in young children; diarrhea (often voluminous) is the predominant symptom
    • Most often affects infants and young children in winter and spring. It was the primary cause of diarrhea in infants and young children in the United States before rotavirus vaccine was developed ⁶
    • Spread via fomites, accounting for ease of transmission
    • Virus is shed in stools for up to 21 days after symptom onset ¹²
  • Norovirus
    • Common cause of acute diarrhea in winter months
    • Responsible for most gastroenteritis outbreaks in all age groups. Outbreaks often occur in schools, day care centers, cruise ships, and other group settings
    • Predominant symptom is severe vomiting lasting 12 to 60 hours ¹
    • Virus may be shed in stools for 2 weeks after recovery ¹
  • Astrovirus
    • Common cause of diarrhea in winter months
    • Virus is shed for several weeks after symptom onset
  • Enteric human adenovirus types 40 and 41, human coronaviruses, and some picornaviruses also are documented causes of diarrhea ¹
• Bacterial (15%-20%) ¹
  • Bacterial (noninflammatory)
    • Foodborne illness caused by preformed toxins that contaminate food before ingestion
      • Staphylococcus aureus
        • Transmitted by dairy products, eggs, meat, and salads; often found in picnic foods and transmitted by food handler
        • Incubation period is 1 to 6 hours; spontaneous recovery in 24 hours is usual ¹
        • Preformed heat-stable toxin affects small intestine with profuse vomiting and abdominal cramping
      • Bacillus cereus
        • Transmitted by starchy foods (eg, rice), vegetables, beef, and pork; often found in picnic foods and transmitted by food handler
        • Incubation period is 1 to 6 hours; spontaneous recovery in 24 hours is usual ¹
        • Preformed heat-stable toxin affects small intestine with profuse vomiting and abdominal cramping
    • Food- or waterborne illness caused by organisms that produce toxin after ingestion
      • Clostridium perfringens
        • Transmitted by beef, pork, poultry, and home-canned goods
        • Incubation period is 4 to 6 hours; 24-hour self-limited symptom duration ¹
        • Presents with frequent watery stools and abdominal cramping
      • Enterotoxigenic Escherichia coli
        • Transmitted by food or water contaminated with fecal material (usually related to cattle) and undercooked meat
        • Incubation period is 1 to 2 days after ingestion; 72-hour (or less) self-limited symptom duration ¹
        • Presents with moderate to severe diarrhea
      • Vibrio cholerae
        • Transmitted by fecal-oral route via contaminated water and occasionally food (eg, shellfish)
        • Vibrio cholerae has an aquatic reservoir, preferring brackish water
        • Incubation period is 12 hours to 5 days ¹³
        • Characterized by sudden-onset voluminous diarrhea with rapid progression to dehydration and shock
  • Bacterial (inflammatory)
    • Invasive infections transmitted by food, water, or direct contact; some are toxin producing in addition to having other invasive mechanisms
      • Campylobacter jejuni
        • Most common cause of investigated foodborne illness ²
        • Transmitted by: ¹
          • Undercooked poultry, raw milk, or cheese
          • Contaminated water
          • Infected animals (eg, poultry, newborn puppies)
          • Person to person contact
        • Typically affects children younger than 5 years ¹
        • Usual incubation period is 1 to 6 days ^1 2
        • Presents with fever, headache, and malaise, followed by abdominal pain, vomiting, and diarrhea lasting 5 to 14 days ¹
      • Salmonella species
        • Transmitted by consuming contaminated animal food products (including eggs and dairy), peanuts, and produce; person to person contact; and handling ducklings and turtles and other reptiles (approximately 5% of cases ²)
        • Salmonella typhi
          • Most invasive serotype
          • Incubation period is 6 to 30 days ¹⁴
          • Presents with enteric fever (ie, typhoid fever), a systemic syndrome characterized by fever, bacteremia, intestinal hemorrhage, and perforation; often fatal without treatment
          • Endemic in South Asia, Southeast Asia, Africa, South America, and Eastern Europe
        • Nontyphi strains ¹
          • Usual incubation period is 6 to 48 hours
          • Presents with vomiting, fever, abdominal pain, and diarrhea with or without blood, which last 2 to 5 days if no complications occur
        • Prolonged fecal excretion over several weeks is common with salmonella infection
          • Chronic carrier state can develop in which bacteria reside in the gallbladder and are excreted for over a year
            • Rare in children ²
      • Shigella species
        • Transmitted by fecal oral route via contaminated fomites, food, water, or person to person contact (low infective dose of 10-100 organisms); ² humans are reservoir for these invasive, toxin-producing bacteria
        • Incubation period is 1 to 6 days ¹
        • Presents with fever, abdominal pain, and bloody diarrhea, which last 2 to 5 days ¹
        • Untreated patients shed bacteria in stool for up to 2 weeks; symptoms recur in approximately 10% of patients ¹
      • Enterohemorrhagic Escherichia coli (eg, serotype O157)
        • Transmitted by: ²
          • Undercooked animal food products (eg, beef)
          • Contaminated water, raw milk, and vegetables
          • Unpasteurized apple cider
          • Petting zoos
          • Day care centers
          • Person to person contact (low infective dose of fewer than 100 organisms)
        • Produces a Shigella-like verotoxin
        • Usual incubation period is 3 to 4 days ¹
        • Presents with bloody diarrhea, vomiting, and elevated WBC count, which last up to 1 week if no complications occur; fever is typically absent
      • Yersinia enterocolitica
        • Transmitted by contaminated pork, raw milk, and water; handling of farm animals and occasionally pets; and person to person contact
        • Incubation period is 4 to 6 days ¹⁵
        • Presents with fever, watery stools, and abdominal pain; sometimes associated with a pseudoappendicitis presentation owing to mesenteric lymphadenitis
        • Associated with more invasive disease in patients with chronic iron overload (eg, patients taking deferoxamine for iron chelation therapy)
      • Vibrio parahaemolyticus
        • Uncommon in the United States, but common in Asia, Africa, Central America, and South America
        • Transmitted by contaminated seafood (specifically from the Gulf of Mexico, including shellfish), food, or water
        • Usual incubation period is 6 hours to 4 days ¹
        • Produces a heat-stable enterotoxin
        • Presents with severe watery diarrhea, abdominal cramping, and vomiting, which last 1 to 3 days ¹
  • Bacterial (antibiotic associated) ¹
    • Clostridioides difficile colitis
      • Primarily occurs in hospitalized patients; risk increases with treatment length and number and type of antibiotics used
        • Fluoroquinolones, clindamycin, cephalosporins, and penicillins are most often associated with Clostridioides difficile colitis
        • Use of proton pump inhibitors increases risk of infection
        • Immunocompromised patients are at higher risk of infection ¹
      • Ingested spores produce toxins that result in secretory diarrhea, inflammation, and mucosal injury and ulceration
        • Spores are resistant to alcohol-based hand sanitizer, heat, acid, and many antibiotics
        • Novel, more virulent, and more broadly antibiotic-resistant strains of Clostridioides difficile are emerging; concern exists about possible transmission through animals and retail meat
      • Symptoms can begin during or several weeks after completing antibiotic therapy
        • Presents with moderate watery diarrhea that may progress to more severe presentation with fever, abdominal pain, and profuse (possibly bloody) diarrhea
• Parasitic (10%-15%) ¹
  • Diarrhea produced by protozoa may occur acutely and usually results in a persistent illness. These protozoa include:
    • Giardia
      • Transmitted by ingesting cysts found in streams and contaminated swimming pools or direct person to person contact (eg, day care centers), with a low infective dose
      • Humans are primary reservoir; pets and other animals can harbor infection
      • Incubation period is 1 to 3 weeks ¹⁶
      • Characteristically presents with bloating, flatulence, and explosive, foul-smelling diarrhea
        • Stools may be pale and float in the toilet (fat malabsorption)
      • Excretion of cysts from infected source may persist for months
    • Cryptosporidia
      • Responsible for outbreaks related to day care centers, public swimming pools, contaminated public water (extensive outbreaks), international travel to developing countries, and AIDS-related infections
      • Transmitted via livestock, zoo animals, and household pets; carried predominantly by birds, reptiles, and mammals
      • Incubation period is 1 to 2 weeks ¹⁷
      • Self-limited watery diarrhea is predominant symptom except in patients with immunodeficiency or AIDS, in whom it may be persistent and disabling ¹⁷
    • Amoebae (eg, entamoebae) ¹⁸
      • Cause of diarrhea and dysentery in developing countries. More common in long-term travelers (those who travel longer than 1 month)
      • Transmitted in contaminated food and water or by person to person contact
      • Incubation is several days to several weeks
    • Isospora or Cystoisospora species ¹⁹
      • Cause of self-limited, protracted, profuse diarrhea with constitutional symptoms in tropical and subtropical areas
      • Transmitted by ingesting contaminated food or water
      • Incubation period is about 1 week
      • Can cause chronic, profuse, wasting diarrhea in patients with HIV or AIDS
    • Cyclospora ¹⁹
      • Causes watery diarrhea which, without treatment, may be prolonged and relapsing over a course of weeks or months
      • Occurs in tropical and subtropical environments; has been associated with foodborne outbreaks in the United States stemming from imported fruits and vegetables
      • Incubation period is 2 days to more than 2 weeks ²⁰
• Traveler’s diarrhea (Related: Traveler’s Diarrhea)
  • Consider if symptoms develop within 10 days of return from a developing country ¹
  • Most cases have a bacterial origin, and approximately 20% of cases involve more than 1 organism ¹
  • Incubation period is 4 to 14 days; illness typically lasts 1 to 5 days ¹
    • Up to 15% of cases last more than 7 days ¹
  • Typical pathogens include:
    • Enterotoxigenic Escherichia coli, enteroaggregative Escherichia coli, Salmonella species
      • Presents with low-grade fever, watery diarrhea, nausea, and vomiting
    • Campylobacter jejuni, Shigella species
      • Presents with colitis, bloody diarrhea, and tenesmus
    • Cryptosporidia
      • Presents with profuse watery diarrhea

Risk factors and/or associations

Age

• Children younger than 5 years are affected more than older children ³
  • Young children generally have 1 to 5 episodes of acute gastroenteritis yearly ³
  • Infants and children younger than 2 years have highest risk of contracting acute gastroenteritis ³
• Very young children are at higher risk of dehydration from acute gastroenteritis
  • Infants and children younger than 6 months have higher risk of dehydration from rotavirus and enterotoxigenic Escherichia coli ²¹

Other risk factors/associations

• Not breastfed
• Zinc deficiency
• Consumption of contaminated food or water
• Consumption of undercooked meat or poultry
• Exposure to person who is infected with or shedding pathogen
• Attendance at day care or in institution or long-term care facility
• Exposure to pets and farm animals
• Poor handwashing hygiene
• Recent antibiotic use or hospitalization (increases possibility of Clostridioides difficile infection)
• Immunocompromised patients at risk for more severe and invasive disease
• Sickle cell anemia (increases risk of acquiring salmonella and Yersinia enterocolitica infection)
• Recent travel to developing countries

Diagnostic Procedures

Primary diagnostic tools ¹

• History and physical examination are the primary tools used to diagnose acute gastroenteritis and to assess hydration status
  • Validated dehydration scale may help objectively measure degree of dehydration in certain patients, particularly when pre-illness weight is not available ^3 22
  • Use dehydration scales in combination with other criteria to guide need for medical intervention in individual cases ²²
• Routine laboratory testing is not recommended for most children with acute gastroenteritis
  • Obtain an immediate point of care glucose measurement for any child with altered mental status or lethargy ²³
  • Measure electrolytes levels in certain populations
    • Significantly ill-appearing patients
    • Patients who have severe dehydration requiring parenteral fluids, particularly when severity of illness requires hospital admission ^3 7 22
    • Moderately dehydrated children with history and physical examination results inconsistent with severe diarrheal disease ²²
    • Patients with signs of hypernatremia (eg, jittery movements, increased muscle tone, hyperreflexia, convulsions, drowsiness, coma) present on examination ²⁴
  • Obtain blood cultures in the following populations: ²⁵
    • Infants younger than 3 months
    • Children of any age with suspected sepsis or enteric fever, systemic manifestations of infection, immunocompromise, or chronic conditions (eg, hemolytic anemia)
    • Children with a febrile illness of unknown cause who have traveled to or had contact with travelers from enteric fever–endemic areas
• Identification of a specific pathogen by culture, viral testing, or parasitic detection is rarely indicated in the acute setting ¹
  • Limited indications for stool testing include persistent high fever, bloody diarrhea or dysentery, immunocompromised state, significant underlying medical comorbidity, age younger than 3 months, prolonged symptoms, or severe symptoms ^1 25
  • Routine stool cultures for enteric pathogens are designed to detect salmonella, shigella, Campylobacter jejuni, and pathogenic Escherichia coli ²⁵
  • May consider molecular testing, aimed at a broad range of pathogens, when rapid results are clinically important or when nonmolecular tests have failed to establish the diagnosis ^26 27
    • Identifying viral cause can avoid unnecessary antibiotic treatment ⁹
    • Bacterial culture is still routinely required to determine antimicrobial susceptibility
  • Testing for Clostridioides difficile is important if patient has recently been hospitalized, has recently received chemotherapy or antibiotics, or is immunocompromised ¹
• Obtaining fecal WBC test or fecal occult blood test rarely adds pertinent clinical information to diagnosis or treatment and is not routinely recommended ²⁵
• Obtain CBC and electrolyte, BUN, and creatinine levels in patients diagnosed with Shiga toxin–producing Escherichia coli (O157:H7 and other strains) to detect early manifestations of hemolytic uremic syndrome ²⁵

Laboratory

• Basic metabolic panel with electrolyte, glucose, creatinine, and BUN levels ¹
  • Concerning findings generally include:
    • Serum sodium level greater than 150 mEq/L (ie, hypernatremic dehydration) ^11 28
    • Serum glucose level less than 50 mg/dL ²⁹
    • Serum bicarbonate level ³⁰
      • Less than 17 mEq/L consistent with mild to moderate dehydration
      • Less than 13 mEq/L consistent with severe dehydration
    • Any elevation of creatinine level over age-based reference range is concerning for more significant prerenal dehydration or possibly intrinsic renal damage (from severe dehydration or hemolytic uremic syndrome)
• CBC ¹
  • If obtained, it rarely adds to diagnostic considerations in routine cases in children older than 2 months
  • Elevated WBC count with left shift can be seen with bacterial enteritis; it may be a key to the diagnosis of neonatal sepsis
  • Elevated eosinophil count can be seen if gastroenteritis is attributable to multicellular parasites
• Fecal occult blood testing ¹
  • Obtained to confirm presence of blood in stool
  • Positive guaiac test result suggests a bacterial cause; culture is indicated
• Fecal WBC testing
  • May be done if an invasive cause is suspected based on history or presentation
  • Sensitivity and specificity are lacking (70% sensitivity and 50% specificity for inflammatory process) ¹
  • Presence of WBCs in stool Gram stain suggests a possible bacterial cause
• Stool bacterial cultures
  • Results are positive in 1.5% to 5.6% of cases ¹
  • Stool cultures indicated for:
    • Patients with diarrhea accompanied by fever, bloody or mucoid stools, severe abdominal cramping or tenderness, or signs of sepsis ²⁵
    • Patients with large volume rice water stools or history of travel to cholera endemic regions ²⁵
    • Immunosuppressed patients ²⁵
    • Persistent significant symptoms for more than 7 days ³
    • Known community outbreak of bacterial pathogen ^23 25
    • Fecal WBCs present on Gram stain, if obtained
    • Infants younger than 3 months ²³
    • Patients with history of antibiotics ²³
• Viral testing ¹
  • Specific viral testing does not contribute to medical decision-making and is not routinely indicated in an otherwise healthy child. May be indicated in documentation and management of outbreaks in special settings (eg, pediatric ICU)
    • Rapid viral antigen assay detects rotavirus and enteric adenovirus
    • Reverse transcriptase polymerase chain reaction assay detects norovirus
    • Multiplex real time polymerase chain reaction assay simultaneously detects a number of viral fecal pathogens in a single test ^31 32
• Parasitic testing
  • Evaluate stool for ova and parasites; giardia and cryptosporidia antigens are detectable
  • Generally indicated for cases of chronic or persistent diarrhea, bloody diarrhea without fecal WBCs, significant exposure as suggested by history, persistent diarrhea in day care centers, or community waterborne outbreaks ¹
  • 3 separate samples on 3 consecutive days are tested ¹
• Clostridioides difficile toxin assay (using polymerase chain reaction or immunoassay) ¹
  • Indicated if patient has recently been hospitalized, has received chemotherapy or antibiotics, or is immunocompromised
• Blood cultures ²⁵
  • Indicated in the following:
    • Children of any age with suspected sepsis or enteric fever, systemic manifestations of infection, immunocompromise, or chronic conditions such as hemolytic anemia
    • Infants younger than 3 months
    • Children with a febrile illness of unknown cause who have traveled to, or had contact with travelers from, enteric fever–endemic areas

Functional testing

• Several validated dehydration assessment scales are available ^3 7
  • No single scoring system clearly appears to be superior to another ³³
  • Accuracy of clinical scales for dehydration may be suboptimal ^{33 34 35 36}
    • In general, scales are best for identifying children with severe dehydration, but they fail to identify mild dehydration and fail to reliably differentiate between mild and moderate dehydration ⁷
  • Some widely recognized scales include:
    • WHO dehydration scale 

Mild dehydration (less than 5%)	Moderate dehydration (5%-10%)	Severe dehydration (more than 10%)
Well and alert	Restless or irritable	Lethargic or unconscious
Drinking normally, not thirsty	Thirsty, drinks eagerly	Drinks poorly or unable to drink
Normal eyes	Sunken eyes	Sunken eyes
Skin recoil is quick when pinched	Skin recoil is slow when pinched	Skin recoil is very slow when pinched

Caption: For ages 1 month to 5 years in low- and middle-income countries.

Citation: Data from Carson RA et al: Clinical practice guideline for the treatment of pediatric acute gastroenteritis in the outpatient setting. J Pediatr Health Care. 30(6):610-6, 2016; and WHO: The Treatment of Diarrhoea: A Manual for Physicians and Other Senior Health Workers. WHO; 2005.

No or minimal dehydration	Moderate dehydration	Severe dehydration
Infant and older children: thirsty, alert, restless	Infant: lethargic or drowsy Older child: alert, dizzy	Infant: limp, cold, cyanosis Older child: apprehensive, cold, cyanosis
Capillary refill normal	Capillary refill minimally prolonged or prolonged	Capillary refill very prolonged
Tears present	Tears absent	Tears absent
Mucous membranes moist	Mucous membranes dry	Mucous membranes very dry
Eyes normal	Eyes sunken	Eyes deeply sunken
Breathing normal	Breathing deep	Breathing deep and rapid
Pulse quality normal	Pulse quality weak or thready	Pulse quality feeble or impalpable
Skin elasticity demonstrates instant recoil	Skin elasticity demonstrates slow recoil	Skin elasticity demonstrates more than 2 second recoil
Heart rate normal	Tachycardia	Tachycardia
Urine output normal	Urine output reduced	No urine output for many hours

Caption: For children aged 1 month to 5 years. Scoring of 4-point scale uses only mucous membrane, eye, breathing, and quality of pulse findings: 2 or more clinical signs are consistent with moderate dehydration (5% or greater body weight change), and 3 or more clinical signs are consistent with severe dehydration (10% or greater body weight change). Scoring of 10-point scale: 3 or more clinical signs are consistent with moderate dehydration (5% or greater body weight change) and 7 or more clinical signs are consistent with severe dehydration (10% or greater body weight change).

Citation: Data from Carson RA et al: Clinical practice guideline for the treatment of pediatric acute gastroenteritis in the outpatient setting. J Pediatr Health Care. 30(6):610-6, 2016; and Pringle K et al: Comparing the accuracy of the three popular clinical dehydration scales in children with diarrhea. Int J Emerg Med. 4:58, 2011.

0 points	1 point each	2 points each
General appearance normal	Thirsty, restless, or lethargic but irritable when touched	Drowsy, limp, cold, and/or comatose
Eyes normal	Eyes slightly sunken	Eyes very sunken
Mucous membranes moist	Mucous membranes sticky	Mucous membranes dry
Tears present	Decreased tears	Absent tears

Caption: Total score: 0, no dehydration (less than 3%); 1 to 4 points, some degree of dehydration (3%-5%); 5 to 8 points, moderate dehydration (6% or greater).

Citation: Data from Carson RA et al: Clinical practice guideline for the treatment of pediatric acute gastroenteritis in the outpatient setting. J Pediatr Health Care. 30(6):610-6, 2016; and Pringle K et al: Comparing the accuracy of the three popular clinical dehydration scales in children with diarrhea. Int J Emerg Med. 4:58, 2011.

• Overall clinical assessment of dehydration status includes: ³⁹
  • Mild dehydration (less than 5% fluid deficit)
    • Weight loss: up to approximately 5%
    • Appearance: alert, active
    • Capillary refill: within reference range
    • Pulse: within reference range
    • Respiration: within reference range
    • Blood pressure: within reference range
    • Mucous membranes: moist
    • Tears: present
    • Eyes: normal appearance
    • Turgor: skin springs back
    • Fontanelle: normal appearance
    • Urine flow: within reference range
  • Moderate dehydration (6%-10% fluid deficit)
    • Weight loss: approximately 6% to 10%
    • Appearance: irritable but alert, thirsty
    • Capillary refill: slightly delayed
    • Pulse: rapid, low volume
    • Respiration: rapid
    • Blood pressure: within reference range or low; orthostatic hypotension
    • Mucous membranes: dry
    • Tears: scant volume
    • Eyes: normal appearance
    • Turgor: skin tents briefly
    • Fontanelle: sunken slightly
    • Urine flow: reduced
  • Severe (more than 10% fluid deficit)
    • Weight loss: greater than approximately 10%
    • Appearance: lethargic, ill-appearing
    • Capillary refill: delayed
    • Pulse: rapid, thready
    • Respiration: rapid, deep
    • Blood pressure: low
    • Mucous membranes: parched
    • Tears: absent
    • Eyes: sunken
    • Turgor: prolonged skin tenting
    • Fontanelle: sunken significantly
    • Urine flow: severely reduced

Differential Diagnosis

Most common

• Extraintestinal infections
  • Vomiting, diarrhea, and fever are nonspecific symptoms associated with other illnesses (eg, otitis media, streptococcal pharyngitis, pneumonia, urinary tract infections, bacteremia, meningitis)
  • Do not dismiss the sole symptom of vomiting in children as early gastroenteritis; differential diagnosis for vomiting in children of different age groups is wide
    • Carefully monitor a child with vomiting only with appropriate work-up as determined by history and physical examination in acute setting
  • Suspect extraintestinal infection if child has the following:
    • Dysuria or suprapubic tenderness
    • Ear pain or signs of otitis media on examination
    • Sore throat, rash, recent contact with streptococcal infection, or pharyngitis on examination
    • Cough, difficulty breathing, or tachypnea
    • Paroxysmal irritability, headache, altered mental status, meningeal signs, or bulging fontanelle
    • Fever of 40 °C or higher, fever of 39.1 °C or higher for more than 2 to 3 days, or fever that develops after initial afebrile period associated with diarrheal illness ^37 40
  • Of note, acute gastroenteritis can be misdiagnosed in children when underlying issue is urinary tract infection
    • At times, diarrhea can contaminate urinary tract in child wearing diapers, resulting in bacterial urinary tract infection
    • Children at higher risk for urinary tract infection include girls, uncircumcised boys, children with previous urinary tract infection, or children with underlying urologic abnormalities
    • Consider urine testing in this population when fever is very high (above 40 °C), fever persists for longer than 2 to 3 days, or child develops fever after several days of diarrhea ^37 40
  • In most cases, history and physical examination will separate extraintestinal infections from acute gastroenteritis; if diagnosis is in question, testing directed by clinical suspicion is warranted
• Toddler’s diarrhea
  • Self-resolving chronic diarrhea thought to be result of rapid gastrointestinal transit in some toddlers
  • Occasionally, a history of high-volume juice intake is associated with this disorder
  • May be mistaken for infectious gastroenteritis initially, but the evolving pattern over time will differentiate this disorder from diarrhea associated with acute gastroenteritis
• Medication-associated diarrhea
  • Antibiotics, excessive laxative use, sorbitol, colchicine, cardiac antidysrhythmics, NSAIDs, chemotherapeutics, and antacids may cause diarrhea
  • History of medication use, absence of fever, and chronicity of symptoms differentiate medication-associated diarrhea from acute gastroenteritis
• Appendicitis
  • Can present with vomiting, low-grade fever, and diarrhea; pain is initially generalized but becomes focal to right lower quadrant
    • Diarrhea does not exclude diagnosis of appendicitis
    • Younger children can present with higher fevers
  • Typically, child will have pain with ambulation or movement as peritoneal irritation becomes more prominent
  • Examination will display focal rebound tenderness in right lower quadrant
  • Course of illness and serial physical examinations may differentiate appendicitis from gastroenteritis; in general, if diagnosis of appendicitis cannot be excluded, imaging by CT or ultrasonography is necessary
• Constipation with overflow incontinence
  • Can present with intermittent abdominal pain and occasionally vomiting
  • History of very large stool passage and infrequent painful stools is usually noted
  • Overflow passage of liquid stools can occur, mimicking diarrhea with a large stool burden
  • Abdomen full of stool can be palpable on physical examination; large hard stool burden is palpable in rectal vault
  • History and physical examination point to diagnosis of constipation with overflow; if diagnosis is uncertain, abdominal radiograph will show large stool burden and absence of air/fluid levels typically seen with acute gastroenteritis
• Intussusception
  • Bowel obstruction in children that develops at ileocecal junction and usually presents with acute onset of vomiting and abdominal pain
  • Vomiting becomes bilious and pain is severe, colicky, and unremitting; bloody stools can develop
  • On examination, right-sided abdominal mass is palpable and stool test results are usually guaiac-positive
  • If intussusception is a consideration, confirm diagnosis with abdominal imaging (eg, plain radiographs, ultrasonography, enema with contrast material)
• Irritable bowel syndrome (Related: Irritable Bowel Syndrome)
  • Common functional gastrointestinal disorder defined by presence of chronic or recurrent abdominal pain, bloating, and variable changes in bowel habits (often including diarrhea) without any other abnormality found to explain symptoms
  • Physical examination is often unremarkable with no evidence of weight loss or other underlying chronic disorders
  • History, physical examination, and course of illness differentiate irritable bowel syndrome from acute gastroenteritis
• Malabsorption syndromes
  • Numerous clinical entities can cause malabsorption of carbohydrates, lipids, or proteins, including:
    • Celiac disease (Related: Celiac Disease)
    • Cystic fibrosis (Related: Cystic Fibrosis)
    • Congenital digestive enzyme deficiencies
    • Transient malabsorption after acute gastroenteritis (specifically if caused by rotavirus)
    • Secondary to hepatic, pancreatic, and intestinal diseases
  • History of diarrhea, weight loss, abdominal pain, and distention is typical
  • Course of illness, history of weight loss, and physical finding of failure to thrive typically exclude acute gastroenteritis from differential diagnosis
• Protein intolerance
  • Cow milk protein, soy protein, and egg proteins are frequent antigenic offenders
  • Presentation can consist of gastrointestinal (eg, vomiting, diarrhea, abdominal pain), cutaneous (eg, rashes), and respiratory (eg, cough, wheezing) manifestations
  • Subcategories of food-related protein intolerance include:
    • Eosinophilic gastroenteritis
    • Food protein–induced enterocolitis syndrome
    • Gluten-sensitive enteropathy (eg, celiac disease) (Related: Celiac Disease)
    • Food protein–induced enteropathy
    • Protein-losing enteropathy
  • Disease is differentiated from acute gastroenteritis by history, chronicity, dietary manipulation, and in some cases, by specific testing (eg, celiac); initial presentation may be mistaken for acute gastroenteritis
• Inflammatory bowel disease
  • Crohn disease and ulcerative colitis ⁴¹
    • Both conditions are forms of inflammatory bowel disease with up to 25% of patients diagnosed before age 20 years ⁴¹
      • Crohn disease can cause transmural inflammation throughout gastrointestinal tract in patchy fashion (Related: Crohn Disease)
      • Ulcerative colitis typically only affects mucosa of colon in continuous manner, starting in rectum (Related: Ulcerative Colitis)
    • Clinical presentation is variable, with diarrhea, abdominal pain, weight loss, bloody stools, and extraintestinal manifestations (eg, chronic intermittent fever, erythema nodosum, pyoderma gangrenosum, anterior uveitis, arthritis) ⁴¹
    • Examination can reveal acute abdomen if peritonitis is present; many patients with Crohn disease have perianal findings (eg, skin tags, perirectal abscess, fistula) ⁴²
    • Laboratory studies demonstrate anemia, hypoalbuminemia, and elevated acute phase reactants (eg, C reactive protein, erythrocyte sedimentation rate)
    • Disease is differentiated from acute gastroenteritis by its chronic nature, but initial presentation may be mistaken for acute gastroenteritis
• Intestinal obstruction
  • Intestinal obstruction from volvulus, Hirschsprung disease, or other causes (eg, history of abdominal surgery, especially bowel resection) can initially present with diarrhea followed by absence of stool passage (Related: Small-Bowel Obstruction)
    • Hirschsprung disease is primarily diagnosed in infants, but it may present as late-onset short segment (Related: Congenital Megacolon)
  • Vomiting becomes bilious; pain is severe, localized, or both (Related: Large-Bowel Obstruction)
  • Physical examination reveals abdominal distention and rebound tenderness
  • Abdominal radiographs show signs of obstruction and differentiate from acute gastroenteritis
• Diabetic ketoacidosis (Related: Diabetic Ketoacidosis)
  • Can present with vomiting, abdominal pain, and severe dehydration
  • Preceding history of polyuria, polydipsia, nocturia, and weight loss is elicited
  • Examination may be suspicious for Kussmaul respiration pattern and breath may smell of ketones
  • History, physical examination, and serum glucose levels differentiate diabetic ketoacidosis from acute gastroenteritis
• Meckel diverticulum
  • Inflammation of common embryonic remnant (ie, omphalomesenteric duct) that presents with hematochezia and less frequently obstruction
  • Rule of twos ⁴³
    • Remnant is usually 2 ft (61 cm) proximal to ileocecal valve
    • Remnant is 2 cm wide
    • Found in 2% of population
    • Often presents by age 2 years
    • 2 times more clinically symptomatic in boys
    • Contains ectopic mucosa about half of the time
  • Notoriously difficult to diagnose but can be differentiated from dysentery by negative stool culture
• Necrotizing enterocolitis
  • Acute inflammatory condition of intestinal tract in neonates; ranges from mucosal injury to necrosis and perforation with sepsis
  • Occurs primarily in second to third week of life in premature infants; rarely, in term infants at 1 to 3 days of life ⁴⁴
  • Symptoms include vomiting, diarrhea, bloody stools, refusal to feed, and hematochezia; signs include pallor, shock, and distended and tender abdomen
  • Age at presentation and physical examination set apart this sometimes devastating condition from acute gastroenteritis
• Toxic ingestion
  • Organophosphates, poisonous mushrooms, arsenic, ciguatera, or scombroid ingestion can present with diarrhea
    • History of exposure and toxidrome on examination is used to differentiate various noninfectious toxin-related causes of diarrhea
  • Iron ingestion can present with bloody stools
    • Patients with acute iron toxicity can present with vomiting, diarrhea, and abdominal pain followed by hemorrhagic gastroenteritis after a toxic amount of iron ingestion (Related: Acute Iron Toxicity)
    • History may suggest iron ingestion (eg, children’s or prenatal vitamins that look like candy may be taken in excess)
    • Positive anion gap metabolic acidosis may be associated with iron toxicity
    • If iron ingestion remains a possibility, further work-up is indicated, including serum iron levels

How is Gastroenteritis in children treated?

• Rehydration with oral rehydration therapy or parenteral fluids when necessary ³
• Prevent dehydration and complications from ongoing gastrointestinal fluid losses (eg, electrolyte abnormalities, hypoglycemia)
• Provide symptomatic care and treat hypoglycemia when present
• Use antibiotics judiciously, only when indicated

Disposition

Admission criteria

Admission is required to manage significant comorbidities, primary underlying illness, and empiric antibiotics; to monitor for clinical deterioration; and to acquire needed consultations

• Comorbidities may include immunocompromised state, uncontrolled diabetes, and sensitive fluid status (eg, in renal, liver, or heart failure; taking diuretics)

Clinical or laboratory evidence of significant or severe dehydration at presentation requires hospitalization for continued fluid replacement and monitoring for clinical deterioration

• Hypernatremia with sodium level higher than 150 mEq/L requires admission for maintenance fluids until adequate oral rehydration therapy is tolerated and urine output is established ²⁸
• Persistent hypoglycemia with glucose level lower than 50 mg/dL requires admission for maintenance fluids until adequate oral fluids are tolerated and glucose is stable ²⁹
• Serum CO₂ level less than 13 mEq/L indicates metabolic acidosis due to poor perfusion and requires admission ³⁰

Persistent toxic appearance despite IV rehydration requires admission for further management, monitoring for clinical deterioration, and further work-up as may be indicated by evolving course of illness

Continued persistent emesis after administration of ondansetron and IV fluids in emergent setting requires hospitalization, monitoring, and further work-up

Evidence of new renal dysfunction (prerenal or intrinsic) requires admission for fluid management, further work-up to determine cause of renal insufficiency, potential inpatient nephrology consultation, and monitoring for clinical deterioration

Significant, persistent abdominal tenderness on serial examinations requires admission for close monitoring, continued fluid management, possible inpatient surgery consultation, and further work-up

Conditions for safe follow-up and home management are not met ²²

Criteria for ICU admission

• Clinical signs of hypotensive (decompensated) shock at presentation or unexplained compensated shock resistant to fluids during initial management
• Severe hypernatremic dehydration (sodium 170 mEq/L or greater) ²⁸
• Significant comorbidities including dialysis-dependent renal dysfunction, heart failure, and liver failure
• Persistently low glucose levels requiring frequent monitoring

Recommendations for specialist referral

• Consult infectious disease specialist if uncertain about indication for antibiotic use in any patient with infectious gastroenteritis and in patients with multidrug-resistant bacterial disease
• Consult surgeon immediately if there is any clinical suspicion for peritonitis, appendicitis, toxic megacolon, or acute abdominal process
• Consider consulting gastroenterologist for patients in whom diagnosis is in question who have prolonged or chronic gastroenteritis symptoms and for those with other preexisting diagnosis managed by gastroenterology service (eg, inflammatory bowel disease, including Crohn disease and ulcerative colitis; Hirschsprung disease; intestinal surgical resection; short gut syndrome)
• Consult nephrologist for any change in renal function or suspicion of hemolytic uremic syndrome as indicated by abnormal renal function test results or persistent diminished urine output

Treatment Options

Rehydration is mainstay treatment for dehydration caused by acute gastroenteritis in children

• Oral rehydration is preferred in patients with mild to moderate dehydration ⁴⁵
  • Common approach to management of a stable but mildly to moderately dehydrated child in the emergency setting ³
    • First a trial of oral rehydration
    • If child cannot be rehydrated orally owing to persistent vomiting, administer a dose of ondansetron if there are no contraindications to facilitate oral rehydration and to diminish need for IV or nasogastric rehydration ^{7 46 47 48}
  • Adequate rehydration is evident by improved clinical status with normalization of vital signs, improved mental status, established urine output, and ability to tolerate oral fluids
  • Monitor and reassess for clinical rehydration; most patients can be safely discharged home with appropriate follow-up
• Nasogastric instillation of fluids or parenteral hydration is required for: ⁷
  • Severe dehydration
  • Moderate dehydration with inability to take oral fluids despite receiving antiemetic therapy

Symptomatic treatment may include antiemetics, antipyretics, bismuth, or zinc preparations

• Ondansetron is safe and effective to facilitate oral rehydration when persistent vomiting impedes it ³
  • Single dose of ondansetron in patients with mild to moderate dehydration will control vomiting in many cases and avoid need for IV fluid administration and hospitalization. It may also facilitate earlier discharge from emergency care settings ^7 49
  • Use of ondansetron does not appear mask alternate underlying serious diagnosis when used during initial acute care visit for vomiting related to suspected gastroenteritis ⁵⁰
    • Data are lacking regarding impact or risks for use of ondansetron after discharge; use after discharge is not routinely recommended ⁷
• Bismuth and zinc preparations have limited indications ⁷
  • Zinc supplementation has been shown to reduce duration and severity of diarrhea in children older than 6 months living in regions with high prevalence of zinc deficiency or malnutrition ⁵¹
  • Bismuth subsalicylate is primarily indicated for traveler’s diarrhea; it is not routinely recommended for use in children with typical acute gastroenteritis ^7 52
    • Contains antisecretory, antiinflammatory, and mild antimicrobial properties
    • Can reduce frequency and duration of diarrhea but requires frequent dosing (ie, every 4 hours) and holds potential risk for salicylate toxicity ⁷
• Probiotics may be offered to reduce symptom duration and severity ²⁵
  • Findings are mixed; some studies have reported decreased duration of diarrhea and stool volume, but other studies have found no improvement in outcomes ^{7 53 54 55 56}
• Avoid antimotility agents in children ^22 25
  • Antimotility agents can diminish stool frequency but do not alter course of infection
  • Antiperistaltics are contraindicated for enterohemorrhagic Escherichia coli (owing to increased risk for hemolytic uremic syndrome) and Clostridioides difficile colitis (owing to risk for toxic megacolon)

Empiric antibiotic therapy ²

• Avoid using empiric antibiotics for otherwise healthy, well-appearing patients, even in cases of high suspicion (eg, Shigella in child presenting with bloody diarrhea who attends day care center where there is a Shigella outbreak) ^7 24 25
  • Severe bloody diarrhea in an afebrile patient raises possibility of enterohemorrhagic Escherichia coli; in this patient, empiric antibiotics may increase risk of developing hemolytic uremic syndrome and worsen outcome ²
  • Obtain appropriate stool cultures and begin directed antibiotics, only when indicated, based on positive culture results or proven Clostridioides difficile colitis ⁷
• Consider empiric antibiotic use for the following patient populations with bloody diarrhea pending culture results: ²⁵
  • Infants younger than age 3 months with suspected bacterial cause
  • Ill-appearing patients with fever, abdominal pain, bloody diarrhea, dysentery (presumed Shigella)
  • Recent international travel with fever and/or signs of sepsis (Related: Traveler’s Diarrhea)
  • Patients with significant medical comorbidities, chronic illness, or immunocompromise and suspected invasive disease
  • Premature infants and febrile infants aged 28 days or younger
• Empiric antibiotic choice
  • Chose antibiotic based on local prevalence and resistance patterns among the most common 3 pathogen species: Shigella, Campylobacter, and Salmonella ²²
  • Recommended antibiotic choices include azithromycin and a third-generation cephalosporin for infants younger than 3 months when empiric treatment is deemed appropriate ²⁵
  • In severely ill patients, empiric regimens need to include coverage of other age-appropriate potential causes of sepsis in addition to likely gastrointestinal pathogens
  • Empiric antibiotics for traveler’s diarrhea include: ^27 57 (Related: Traveler’s Diarrhea)
    • Azithromycin given as a single dose or 3-day dosing ⁵²
    • Fluoroquinolones and rifaximin are additional options; avoid fluoroquinolones in children unless there are no appropriate alternatives ⁵⁸

Pathogen-directed therapy based on positive culture results is recommended only for certain offending bacterial pathogens in certain clinical situations, guided by culture sensitivity results ^2 11

• Clinical situations warranting directed antibiotic use:
  • Immunocompromised patients
  • Patients with other comorbidity or chronic illness (eg, cardiopulmonary or renal disease, hemoglobinopathy)
  • Severely ill or septicemic patients
  • Confirmed cases of cholera, shigella, giardia, cryptosporidia, amoebae, or enteric fever (typhoid fever); Salmonella gastroenteritis in those who are younger than 6 months or immunocompromised
• Base treatment on results of laboratory susceptibility testing; unless antibiotic resistance is demonstrated, the following regimens are recommended:
  • Escherichia coli species ²²
    • Enterotoxigenic Escherichia coli
      • Give 1 of the following:
        • Azithromycin
        • Trimethoprim-sulfamethoxazole ¹
        • Third-generation cephalosporins ⁵⁹
    • Shiga-toxin producing Escherichia coli (O157:H7 and other strains)
      • Antibiotics are contraindicated with enterohemorrhagic Escherichia coli owing to increased risk for developing hemolytic uremic syndrome ²
      • If an antibiotic has been initiated and Shiga toxin–producing Escherichia coli is cultured, discontinue antibiotic
  • Campylobacter jejuni ²² (Related: Campylobacter Infections)
    • Antibiotic treatment is not indicated in healthy patients because it only shortens course of illness by approximately 1 day ¹
    • Primarily indicated for gastroenteritis associated with dysentery; most efficacious when started within 3 days after onset of disease ²²
    • Drug of choice is azithromycin; choose antibiotic based on local resistance patterns ^22 60 61
  • Salmonella species ²² (Related: Nontyphoidal Salmonella Infection)
    • Antibiotic treatment increases risk for carrier state
    • Treatment is recommended only in certain situations, including:
      • Severe illness, toxic appearance
      • Extremes of age (children younger than 3-6 months) ^1 22
      • Valvular heart disease
      • Uremia
      • Malignancy
      • Immunodeficiency or asplenia
      • Otherwise at risk for metastatic infection or gastroenteritis complications
      • Bacteremia in child younger than 1 year
      • Typhoid fever
    • Give 1 of the following:
      • Third-generation cephalosporin ^1 59
      • Ciprofloxacin ²⁵
      • Azithromycin until patient is afebrile ²
      • Amoxicillin (optimum dose and duration not established) ⁶²
      • Trimethoprim-sulfamethoxazole (optimum dose and duration not established) ⁶²
  • Shigella species ²²
    • Give 1 of the following:
      • Azithromycin ^59 60
      • Ciprofloxacin ^63 64
      • Ceftriaxone ²⁵
      • Cefixime ⁶⁴
  • Yersinia enterocolitica ⁶⁵ (Related: Yersinia enterocolitica Infection)
    • Treatment not indicated for healthy patients without disease; situations in which treatment is recommended are same as for salmonella
    • Give 1 of the following:
      • Trimethoprim-sulfamethoxazole ^15 40
      • Third-generation cephalosporin ^15 59
  • Vibrio parahaemolyticus ^1 2
    • Self-limiting infection rarely warrants antibiotic treatment; wound infections require debridement ⁶⁶
    • Treat severe diarrhea, wound infection, and septicemia with antibiotic therapy; preferred antibiotic options include doxycycline or ciprofloxacin; trimethoprim-sulfamethoxazole and an aminoglycoside is an alternative regimen ⁶⁶
    • Septicemia requires double coverage with third-generation cephalosporin plus doxycycline or ciprofloxacin in combination ⁶⁶
  • Vibrio cholerae ^22 67 (Related: Cholera)
    • Treat moderate to severe illness with 1 of the following:
      • Doxycycline as a single dose or tetracycline for 3 days
      • Azithromycin for 3 days or as a single dose
  • Clostridioides difficile ^1 68 (Related: Clostridioides difficile Infection)
    • Stop the offending antibiotic, if possible ⁶⁹
    • For mild to moderate disease, give either metronidazole or vancomycin for 10 days ⁶⁹
    • For severe disease, give oral vancomycin, with or without metronidazole, for 10 days ⁶⁹
    • Recurrent disease ⁶⁸
      • First recurrence treatment is same as initial treatment
      • Second recurrence options for treatment are:
        • Vancomycin in tapered or pulse dose
        • Vancomycin for 10 days followed by rifaximin for 20 days
        • Fecal microbiota transplant
    • Other experts recommend treating only hypervirulent strains, moderate-severe disease, and mild disease in which diarrhea does not resolve when offending antibiotic is discontinued ²²
  • Cryptosporidia
    • Treatment mainly is indicated in patients who are immunocompromised or those with severe disease ²²
    • Give nitazoxanide ^40 59 70
  • Giardia ^16 59 (Related: Giardiasis)
    • Give 1 of the following:
      • Tinidazole ²⁵
      • Nitazoxanide ¹⁶
      • Metronidazole ¹⁶
  • Amoebae (Related: Amoebiasis)
    • Give metronidazole or tinidazole followed by iodoquinol or paromomycin ^18 71

Institute standard and contact infection control precautions for any patient requiring hospitalization ²²

Hospital evidence-based acute gastroenteritis pathway algorithms are available ²³

Drug therapy

• Antiemetics
  • Ondansetron ⁴⁵
    • Oral
      • Ondansetron Hydrochloride Oral solution; Infants and Children 6 months and older weighing 8 to 15 kg: 2 mg PO as a single dose. Alternatively, 0.2 mg/kg/dose PO every 8 hours for 3 doses has also been studied.
      • Ondansetron Oral disintegrating tablet; Children weighing 15 to 30 kg: 4 mg PO as a single dose. Alternatively, 0.2 mg/kg/dose PO every 8 hours for 3 doses has also been studied.
      • Ondansetron Oral disintegrating tablet; Children and Adolescents weighing more than 30 kg: 6 to 8 mg PO as a single dose. Alternatively, 0.2 mg/kg/dose PO every 8 hours for 3 doses has also been studied.
      • IV preparation may be given orally ⁷
    • IV
      • Ondansetron Hydrochloride Solution for injection; Infants, Children, and Adolescents: 0.15 mg/kg/dose IV as a single dose (Max: 8 mg/dose).
        • Safe dosing is established down to age 1 month; in practice, lower age limit for dosing by convention is 4 to 6 months ⁷
• Antipyretics
  • Acetaminophen
  • Ibuprofen
• Bismuth subsalicylate ²
  • Avoid in children who: ²
    • Are younger than 3 years
    • Have allergy to aspirin
    • Have renal impairment
  • Bismuth Subsalicylate Oral suspension; Adults and Adolescents: 524 mg (30 mL) PO every 30 to 60 minutes, PRN. Max: 8 doses/day.
• Antibiotics
  • Trimethoprim-sulfamethoxazole
    • Sulfamethoxazole, Trimethoprim Oral suspension; Infants and Children 2 months to 12 years: 8 mg/kg/day (trimethoprim component) PO divided every 12 hours (Max: 320 mg trimethoprim/1,600 mg sulfamethoxazole/day) for 5 days.
    • Sulfamethoxazole, Trimethoprim Oral tablet; Adolescents: 8 mg/kg/day (trimethoprim component) PO divided every 12 hours (Max: 320 mg trimethoprim/1,600 mg sulfamethoxazole/day) for 5 days. For HIV-infected patients, treat for 7 to 10 days or extend to at least 14 days with bacteremia; recurrent infection may require up to 6 weeks of treatment.
  • Azithromycin
    • For empiric treatment of traveler’s diarrhea:
      • Azithromycin Oral suspension; Infants, Children, and Adolescents: 10 mg/kg/dose (Max: 500 mg/dose) PO once daily for 3 days.
    • For Salmonella infections, including typhoid fever:
      • Azithromycin Oral suspension; Infants, Children, and Adolescents: 8 to 20 mg/kg/dose (Max: 1 g/dose) PO once daily for 5 to 7 days.
    • For Campylobacter infections:
      • Azithromycin Oral suspension; Children: 10 mg/kg/dose (Max: 500 mg/dose) PO once daily for 3 days.
    • For Shigella infections:
      • Azithromycin Oral suspension; Infants and Children: 12 mg/kg/dose (Max: 500 mg/dose) PO once daily for 1 day, followed by 6 mg/kg/dose (Max: 250 mg/dose) PO once daily for 4 days.
      • Azithromycin Oral tablet; Adolescents: 500 mg PO once daily for 5 days.
    • For Vibrio cholerae infections:
      • Azithromycin Oral suspension; Children and Adolescents: 20 mg/kg/dose (Max: 1 g/dose) PO as a single dose.
  • Cefixime ⁶⁴
    • Cefixime Oral suspension; Infants 6 months and older and Children weighing 45 kg or less: 8 mg/kg/day PO divided every 12 hours. Max: 200 mg/dose.
    • Cefixime Oral capsule; Children weighing more than 45 kg and Adolescents: 200 mg PO every 12 hours.
  • Ceftriaxone
    • For enterotoxigenic Escherichia coli infections:
      • Optimum dose and duration are not established
    • For Salmonella infections:
      • Optimum dose and duration are not established
    • For Vibrio parahaemolyticus infections:
      • Optimum dose and duration are not established
  • Tetracycline
    • For Vibrio parahaemolyticus infections:
      • Optimum dose and duration are not established
  • Doxycycline
    • For Vibrio cholerae and parahaemolyticus infections:
      • Doxycycline Monohydrate Oral suspension; Infants, Children, and Adolescents weighing less than 45 kg: 2.2 mg/kg/dose PO every 12 hours on day 1, then 2.2 to 4.4 mg/kg/day with fluid and electrolyte replacement.
      • Doxycycline Monohydrate Oral suspension; Adults, Adolescents, and Children 8 years and older weighing 45 kg or more: 100 mg PO every 12 hours on day 1, then 100 mg/day with fluid and electrolyte replacement.
  • Ciprofloxacin ⁶⁴
    • For Shigella infections:
      • Ciprofloxacin Oral suspension; Infants† and Children†: 15 mg/kg/dose PO every 12 hours (Max: 500 mg/dose) for 3 days recommended by WHO.
      • Ciprofloxacin Oral suspension; Adolescents†: 15 mg/kg/dose PO every 12 hours (Max: 500 mg/dose) for 3 days recommended by WHO; 500 to 750 mg PO every 12 hours for HIV-infected patients; treat for 7 to 10 days or for at least 14 days with bacteremia; treat recurrent infection for at least 6 weeks.
    • For Vibrio parahaemolyticus infections:
      • Optimum dose and duration are not established
  • Metronidazole
    • For Clostridioides difficile infections:
      • Metronidazole benzoate Oral powder; Infants, Children, and Adolescents: 7.5 mg/kg/dose (Max: 500 mg/dose) PO every 6 to 8 hours for 10 days.
    • For Giardia infections:
      • Metronidazole Oral tablet; Infants, Children, and Adolescents: 15 mg/kg/day (Max: 750 mg/day) PO divided every 8 hours for 5 to 7 days.
    • For amoebic infections:
      • Metronidazole Oral tablet; Infants, Children, and Adolescents: 35 to 50 mg/kg/day (Max: 2,250 mg/day) PO divided every 8 hours for 7 to 10 days.
  • Vancomycin
    • For Clostridioides difficile infections:
      • Vancomycin Hydrochloride Oral solution; Infants, Children, and Adolescents: 10 mg/kg/dose (Max: 125 mg/dose) PO 4 times daily for 10 days.
  • Nitazoxanide
    • For Cryptosporidium infections:
      • Nitazoxanide Oral suspension; Children 1 to 3 years: 100 mg PO every 12 hours with food for 3 days. In HIV-infected patients, clinical guidelines suggest treating for 14 days.
      • Nitazoxanide Oral suspension; Children 4 to 11 years: 200 mg PO every 12 hours with food for 3 days. In HIV-infected patients, clinical guidelines suggest treating for 14 days.
      • Nitazoxanide Oral suspension; Children 12 years: 500 mg PO every 12 hours with food for 3 days. In HIV-infected patients, clinical guidelines suggest treating for 14 days.
    • For Giardia infections:
      • Nitazoxanide Oral suspension; Children 1 to 3 years: 100 mg PO every 12 hours with food for 3 days.
      • Nitazoxanide Oral suspension; Children 4 to 11 years: 200 mg PO every 12 hours with food for 3 days.
      • Nitazoxanide Oral suspension; Children and Adolescents 12 to 17 years: 500 mg PO every 12 hours with food for 3 days.
  • Tinidazole ¹⁶
    • For amoebic infections:
      • Tinidazole Oral tablet; Children and Adolescents 4 to 17 years: 50 mg/kg/dose (Max: 2 g/dose) PO once daily for 3 days.
    • For Giardia infections:
      • Tinidazole Oral tablet; Children and Adolescents 4 to 17 years: 50 mg/kg/dose (Max: 2 g/dose) PO as single dose.
• Probiotic supplements
  • Lactobacillus rhamnosus GG ⁷²
    • Lactobacillus Rhamnosus Chewable tablet or oral solution; Children: 10 billion colony-forming units/day PO for 5 to 7 days. ³
  • Saccharomyces boulardii ⁷³
    • Saccharomyces boulardii Chewable tablet; Children and Infants: 250 to 750 mg/day PO for 5 to 7 days. ^3 7
• Zinc
  • Zinc supplementation (elemental zinc) Oral tablet; Children 6 months to 5 years: 10 to 20 mg/day of elemental zinc PO in divided doses for 10 to 14 days. ^3 37

Nondrug and supportive care

• Hydration
  • Oral rehydration therapy ^30 59
    • Mainstay treatment of acute gastroenteritis in children
      • Oral rehydration success rate exceeds about 95% for children with mild to moderate dehydration ³
    • Maintain oral hydration to prevent dehydration whenever possible
      • Frequent small amounts of fluid are recommended in children with persistent emesis
    • For mild to moderate dehydration:
      • Consider a single sublingual dose of ondansetron before initiating oral rehydration, particularly for patients with frequent vomiting
      • Wait 30 to 45 minutes after the dose and begin rehydration with slow and frequent amounts of fluid ⁷⁴
        • Consider first offering the child a frozen, fruit-flavored, oral rehydration solution ice pop ^22 74
        • Begin initial consumption of liquid with a few milliliters (5-10 mL) every 5 minutes during the first 30 minutes ⁷
        • Once initial small, frequent amounts are tolerated, increase amount consumed by 5 mL increments over approximately the next 30 minutes ⁷
      • Goal amounts of oral rehydration solution for rehydration process
        • Goal is 50 mL/kg over 4 hours with signs of mild dehydration plus replacement for losses ^1 30
        • Goal is 100 mL/kg over 4 hours with signs of moderate dehydration plus replacement for losses ³⁰
        • Replacement for losses
          • Give additional 2 ounce or 10 mL/kg oral rehydration solution for each episode of watery diarrhea or bout of emesis ³
      • Oral rehydration solutions
        • Preferred solutions include either of the following:
          • Commercial electrolyte solutions for pediatric patients
          • Oral rehydration solution packets
            • Available as powders that combine with 1 L clean water
            • WHO recommends a reduced osmolarity formula of less than 270 mOsm/L ⁷⁵(eg, 75 mmol/L sodium, 20 mmol/L potassium, 65 mmol/L chloride, 10 mmol/L citrate, 75 mmol/L glucose) rather than the original standard oral rehydration solution formula of more than 310 mOsm/L ⁷⁵(eg, 90 mmol/L sodium, 20 mmol/L potassium, 80 mmol/L chloride, 10 mmol/L citrate, 111 mmol/L glucose) ³⁷
        • Commercial sports drinks do not contain enough salt
          • Some experts suggest addition of half a teaspoon of salt per 32 ounces of commercial sports drink if this is the only option available ³
        • Other liquids (eg, soup, water, juices) may not contain optimal ratios of sugar and salts to promote intestinal absorption and avoid osmotic diuresis
          • Limited data suggest that diluted apple juice (half-strength) may be an effective initial oral rehydration solution alternative for children who have minimal dehydration ⁷⁶
        • Home oral rehydration solution ¹
          • Not routinely recommended in developed countries where commercial formulations are readily available owing to potential for mixing errors ⁷
          • Can be approximated by the following recipe, using 1 L clean water:
            • Half teaspoon salt/L
            • Half teaspoon baking soda/L
            • 4 teaspoons sugar/L
      • Instruct parents carefully and provide written parameters for rate and amount of administration; caution parents not to exceed recommended parameters
  • IV rehydration ^30 59
    • Parenteral fluids, using isotonic solutions for children older than 1 month
      • Indicated for the following:
        • Moderate to severe dehydration, which may present with:
          • Listlessness or depressed mental status
          • Minimal urine output
          • Significant tachycardia
          • More than 10% weight loss
        • Compensated or hypovolemic (decompensated) shock ¹⁰
      • Fluid management is based on frequent reassessment of clinical hydration status, response to previous measures, and adjustment of ongoing fluid administration
    • For moderate dehydration, administer normal saline or lactated Ringer solution 20 mL/kg ²⁵ IV fluid bolus over 30 to 60 minutes and reassess ²³
      • Additional fluid bolus may be required, depending on degree of fluid deficit and clinical response to fluids
      • Begin oral rehydration therapy plus replacement for losses
      • Child can be safely discharged home with appropriate follow-up if all of the following criteria occur:
        • Fluid deficit is corrected
        • Urine output is established
        • Oral intake is tolerated
      • If child does not meet these criteria, admit to continue maintenance fluids
        • Calculate hourly maintenance fluid requirements based on hourly reference range fluid losses and add fluid losses from illness (eg, vomiting, diarrhea) to calculate total maintenance rate based on weight (4-2-1 rule) ³⁹
          • For first 10 kg of patient weight, hourly fluid requirements are 4 mL/kg/hour
          • For 10 to 20 kg of patient weight, add 2 mL/kg/hour
          • For more than 20 kg of patient weight, add 1 mL/kg/hour
            • Example calculation for child weighing 40 kg: 40 mL/hour + 20 mL/hour + 20 mL/hour = 80 mL/hour + hourly fluid loss from illness in milliliters
        • For children aged 2 months and older, administer IV fluids at maintenance volume plus calculated replacement for losses
          • Avoid hypotonic fluids; guidelines suggest isotonic fluids or 5% dextrose with saline at no less than half normal (0.45%) ²²
          • Limited data suggest that addition of 5% dextrose-containing fluids after the initial resuscitation phase (following isotonic fluid bolus or boluses) may be beneficial ^7 77
          • After establishing urine output or if electrolytes are known to be within reference range, add 20 mEq/L potassium chloride ²²
          • Modify treatment as needed if electrolyte or sodium levels are outside reference range upon presentation
    • For severe dehydration, administer normal saline or lactated Ringer solution 20 mL/kg IV fluid bolus over 10 to 15 minutes and reassess ³⁰
      • Repeat bolus as needed to normalize pulse, blood pressure, capillary refill, mental status, and urine output ³⁰
      • When patient is hemodynamically stable, begin oral rehydration therapy 100 mL/kg over 4 hours and maintenance fluid plus replacement for losses when indicated ³⁰
        • If patient is unable to take oral rehydration solution, give normal saline or lactated Ringer solution 100 mL/kg IV over 4 hours, followed by maintenance fluid plus replacement for losses
  • Nasogastric rehydration
    • Nasogastric rehydration using oral rehydration solution is considered an equally effective option, as compared with IV fluids, for purpose of rehydrating a child with mild to moderate dehydration from acute gastroenteritis ⁷⁸
    • Nasogastric rehydration using oral rehydration solution may have some advantages, including: ⁷
      • Easier to insert nasogastric tube than to place IV line
      • Fewer complications than with IV line placement
      • Shorter emergency department and inpatient hospital stays
• Usually can effectively address hypernatremia in children with acute gastroenteritis by correcting fluid status
  • No other specific management usually is indicated aside from reassessing clinical fluid status, monitoring mental status, and checking sodium level
• Glucose bolus for hypoglycemia
  • Give fluid bolus with glucose; recheck glucose in 30 minutes
    • Neonates: 10% dextrose in water given in 2.5 to 5 mL/kg dose ⁷⁹
    • Child: 25% dextrose in water given in 2 to 4 mL/kg dose ⁸⁰
  • If hypoglycemia persists, consider additional bolus of glucose followed by glucose infusion at appropriate infusion rate for age
  • Check glucose hourly until stable
• Diet
  • Continue unrestricted nursing in breastfeeding infants throughout diarrheal illness ^3 25
  • Early refeeding is an important measure ⁸¹
    • Begin feeding in all patients who are tolerating oral feedings once acute dehydration is corrected ⁸¹
    • Encourage age-appropriate diet containing simple starches, fruits, vegetables, lean meats, and yogurt ^3 82
  • Consider avoiding lactose-containing foods if diarrhea significantly worsens when lactose-containing substances are reintroduced ^7 78
    • Continue age-appropriate diet and consider avoiding significant proportions of substances containing high amounts of lactose for up to 2 weeks ^1 82
  • Avoid high-fat foods until normal bowel function returns
• Probiotics
  • May decrease duration of diarrhea and stool volume when adequately dosed and started early in course of illness ⁷
    • There are conflicting findings; some studies show no benefit ^53 54 55
  • More effective for patients with gastroenteritis of viral cause and of minimal benefit for patients with gastroenteritis of bacterial cause ⁷
  • Current guidelines recommend use with any acute diarrheal illness ^23 25
  • Possible benefits of Lactobacillus rhamnosus GG: ⁷²
    • Decreased stool volume and duration of diarrhea in children with rotavirus and other common viral causes of acute gastroenteritis
    • Minimally decreased diarrhea associated with bacterial pathogens, including those typical for traveler’s diarrhea ⁷
    • Decreases symptoms of Clostridioides difficile infection

Comorbidities

• Children with renal impairment, heart disease, liver disease, or otherwise sensitive fluid status (eg, diuretic use) require rehydration care under guidance of appropriate subspecialist
• Patients who are immunocompromised as a result of medication (eg, corticosteroids) or underlying disease (eg, diabetes, cystic fibrosis) are at risk for pathogenic colonization, more severe infection course, and septicemia ^2 25
• Children with a preexisting gastrointestinal comorbidity, including inflammatory bowel disease (eg, Crohn disease, ulcerative colitis), Hirschsprung disease, prior intestinal surgical resection, or short gut syndrome require close monitoring and management in consultation with gastroenterologist
• Patients receiving proton pump inhibitors are at increased risk for infections from organisms that cause acute gastroenteritis owing to diminished protective effect of gastric acidity against infection ²
• Patients with dysmotility syndromes are at increased risk for infection owing to abnormal intestinal flora and diminished ability to remove pathogens ²
• Patients taking antibiotics are at risk for colonization by antibiotic-resistant pathogens (eg, Clostridioides difficile) and more severe course of illness owing to reduced normal protective intestinal flora ²
• Patients with previous abdominal surgery require careful consideration for obstruction secondary to adhesions, particularly when presenting with primarily vomiting ⁷

Special populations

• Infants
  • Approach to infants requires careful thought regarding a broad differential, particularly those presenting with primarily vomiting without diarrhea

Mild dehydration (less than 5%)	Moderate dehydration (5%-10%)	Severe dehydration (more than 10%)
Oral rehydration therapy (50 mL/kg over 4 hours)	Oral rehydration therapy (100 mL/kg over 4 hours)	IV rehydration (20 mL/kg isotonic fluids over 10-15 minutes), then reassess; repeat fluid boluses as clinically indicated
Encourage regular diet and unrestricted breastfeeding	Defer solids until rehydration complete and encourage unrestricted breastfeeding	Treat hypoglycemia if present on point of care glucose measurement obtained secondary to mental status depression
Consider oral ondansetron in children with ongoing vomiting as adjunct measure to facilitate oral rehydration therapy	Consider oral ondansetron in children with ongoing vomiting as adjunct measure to facilitate oral rehydration therapy	May use IV ondansetron in children with persistent vomiting to facilitate success of oral rehydration therapy when started
Replace ongoing losses	Replace ongoing losses	Closely monitor intake, output, and patient response to all measures
Consider adjunct probiotics	Consider adjunct probiotics	Initiate oral rehydration therapy once hemodynamic stability is achieved
		Assess need for and initiate maintenance IV fluids when indicated
		Replace ongoing losses
		Consider adjunct probiotics when tolerating enteral fluids

Citation: Data from Carson RA et al: Clinical practice guideline for the treatment of pediatric acute gastroenteritis in the outpatient setting. J Pediatr Health Care. 30(6):610-6, 2016; Shane AL et al: 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea. Clin Infect Dis. 65(12):1963-73, 2017.

Monitoring

• Follow-up testing of stool cultures ²⁵
  • Usually not necessary; however, for some infections, documentation of a negative stool culture result may be required to return to school or work
    • Consult state or local health regulations
  • May be required when symptoms do not improve despite initial course of therapy
• Follow-up testing of serum electrolytes ⁴⁰
  • Monitor in children who require ongoing IV fluids every 2 to 3 days
  • Monitor in children with significant abnormalities on initial laboratory results at presentation, when obtained, about every 24 hours with frequency depending on severity of abnormality at presentation ⁸³
• Monitoring during acute management
  • Reassess patient for response after each treatment measure; focus on intake, output, hydration status, and general clinical appearance
    • Weigh inpatients daily
  • If patient fails to respond or condition worsens, investigate potential alternate diagnosis
  • Criteria for discharge home include: ³
    • Active and well-appearing with stable vital signs, soft abdomen, and no more than mild dehydration on examination
    • Tolerating oral fluids in relation to ongoing losses
    • Caregiver able to manage patient at home and follow-up as needed

Complications

• Death
  • Among children, young infants are at highest risk for death from gastroenteritis ¹
    • Mortality for enterohemorrhagic Escherichia coli is 1% to 2%
• Hypernatremia (sodium greater than 150 mEq/L)
  • Suspect with altered mental status, jittery movements, and seizures
• Malabsorption
  • Transient malabsorption is common after some acute gastroenteritis–related illnesses, specifically rotavirus infection
• Transient diaper dermatitis
  • Common in diaper-wearing patients
• Transient lactose intolerance
  • Occasional complication that manifests with precipitous increase in diarrhea as lactose-containing formula or food is introduced ⁸²
  • Lactase enzyme on small intestinal brush border can be depleted with significant diarrheal illness, which results in lactose malabsorption and intolerance
  • Functional lactase deficiency can last up to 2 weeks after infectious gastroenteritis ¹
• Hemolytic uremic syndrome
  • Complicates enterohemorrhagic Escherichia coli in 6% to 9% of patients; mainly in young children ^1 2
    • More than 90% of cases are associated with enterohemorrhagic Escherichia coli O157:H7 serotype; emerging strains of non-O157 are less commonly responsible ²
    • Rarely a complication of shigella or salmonella
  • Children younger than 4 years are at highest risk ¹
  • Empiric antibiotic use increases risk of developing hemolytic uremic syndrome
• Transient reactive arthritis
  • Seen after infection with Salmonella species, Campylobacter jejuni, Yersinia enterocolitica, or Shigella dysenteriae serogroup 1
• Bacteremia
  • Can follow enteric infections with salmonella, Campylobacter jejuni, shigella, and Escherichia coli
  • 5% of patients with salmonella develop transient bacteremia ²
    • Metastatic infection can occur in patients at increased risk (eg, very young, immunocompromised state) resulting in osteomyelitis, abscess, mycotic aneurysm, meningitis, and other deep-seated infection
• Guillain-Barré syndrome (Related: Guillain-Barré Syndrome)
  • Incidence is 1 in 1000 cases after Campylobacter jejuni infections ¹
• Toxic megacolon
  • Occasional severe complication of Clostridioides difficile colitis and Shigella dysenteriae serogroup 1
• Febrile seizures
  • Complication of Shigella dysenteriae serogroup 1 infection in particular 
• Hyponatremia
  • Rare complication of Shigella dysenteriae serogroup 1 infection
• Encephalitis (Related: Encephalitis in Children)
  • Rare complication of Shigella dysenteriae serogroup 1 infection
• Osteomyelitis (Related: Osteomyelitis in Children)
  • Complication with Salmonella infection in patients with sickle cell anemia

Prognosis

• Oral rehydration therapy is the only requirement for successful, uneventful recovery in 95% of otherwise healthy children 
• Prognosis is good with full recovery in most children who develop acute gastroenteritis, as illness is usually viral and self-limited. No long-term adverse effects are expected

Prevention

• Rotavirus vaccination 
  • Universal vaccination of all infants is recommended 
  • Rotavirus vaccination in the United States is responsible for a 67% decrease in symptomatic laboratory test–positive disease 
• Primary prevention
  • Public health measures 
    • Safely treat water
    • Safely handle and prepare food
    • Sanitarily dispose of feces
  • Practice good hand hygiene with soap
• Avoid swimming and water activities until diarrhea resolves 
  • Non–toilet trained patients should avoid swimming in pools for 1 to 2 weeks after last episode of diarrhea 
• Prevention measures for schools and day care environments
  • Exclusion recommendations from school and day care may include:
    • Stools are contained in diaper or child is not having incontinence (American Academy of Pediatrics recommendations) 
    • Stool frequency is no more than 2 stools greater than child’s baseline normal stool frequency (American Academy of Pediatrics recommendations) 
    • More than 48 hours has elapsed following last bout of emesis or diarrhea (National Institute for Health and Care Excellence recommendations) 
• Prevention of enteric bacterial pathogens 
  • Avoid eating undercooked meat
  • Practice safe food storage and preparation
  • Practice good hand hygiene with soap
  • Avoid raw foods and unpasteurized milk in high-risk patient populations (eg, immunosuppressed patients)
• Prevention of traveler’s diarrhea 
  • Water sources
    • Boil or filter water before ingesting
      • Pore size must be less than 0.01 μm to remove viruses; ultrafiltration, nanofiltration, and reverse osmosis filtration systems can remove viruses 
    • Drink bottled water
    • Avoid ice
    • Use a straw instead of drinking from a glass
  • Food selection 
    • Avoid unpeeled fruit or raw vegetables 
    • Avoid eating from steam buffets and street vendors
    • Avoid communal condiments
  • Prophylactic medications
    • Bismuth subsalicylate taken 4 times daily reduces the incidence of traveler’s diarrhea (taken for no longer than 3 weeks) 
    • Consider prophylactic antibiotics (no more than 2-3 weeks) only in specific patient populations when traveling to highly endemic areas 
      • Immunocompromised state
      • Inflammatory bowel disease
      • Renal impairment
      • Significant comorbidities or chronic medical illness
• Establish contact isolation measures for patients with suspected Clostridioides difficile colitis or bacterial gastroenteritis admitted to the hospital

References

1: Graves NS: Acute gastroenteritis. Prim Care. 40(3):727-41, 2013