Approach to the child with acute diarrhea in resource-limited settings

INTRODUCTION — Diarrhea refers to passage of loose or watery stools at least three times in a 24-hour period [1]. Diarrheal illness is an important cause of child mortality; among children <5 years of age worldwide, it caused over 480,000 estimated deaths in 2019 [2].

In resource-limited settings, infants experience a median of six episodes annually, and children experience a median of three episodes annually. There is considerable geographic variability in the incidence and associated mortality of diarrheal illnesses; certain regions may need targeted interventions to improve these outcomes [3,4].

In 2005, the World Health Organization (WHO) issued guidelines for the management of diarrheal illness in resource-limited settings in "The Treatment of Diarrhea: A Manual for Physicians and Other Senior Health Workers" [1].

Issues related to the etiology, clinical assessment, management, and prevention of acute diarrhea in children in resource-limited settings are reviewed here.

Issues related to persistent diarrhea in children in resource-limited settings are discussed separately. (See "Persistent diarrhea in children in resource-limited settings".)

ETIOLOGY — Most cases of acute diarrhea in resource-limited settings are caused by infectious gastroenteritis; patients may present with watery diarrhea or invasive (bloody) diarrhea. Less commonly, acute diarrhea may be a symptom of a systemic infection or an intra-abdominal surgical emergency.

Infectious causes — Causes of diarrhea differ by age group and geographical region. The microbial etiology of watery diarrhea differs from that of invasive (bloody) diarrhea, as discussed below (table 1). (See 'Watery diarrhea' below and 'Invasive (bloody) diarrhea' below.)

In a 2013 study of children <5 years of age in Asia and Africa, stool samples from 9439 children with moderate to severe diarrhea and 13,129 controls were tested for a panel of microorganisms [5]:

●Rotavirus, Cryptosporidium, Shigella, and enterotoxigenic Escherichia coli (ETEC) were important pathogens at all study sites, and most attributable cases of diarrhea were due to these organisms.

●Rotavirus was the most common pathogen among children <2 years of age, whereas Shigella was the most frequently isolated pathogen in children aged two to five years. Cryptosporidium was the second most common pathogen among infants <1 year of age; it was detected infrequently among children >2 years.

●Aeromonas was a frequent pathogen in Pakistan and Bangladesh; Campylobacter jejuni was a frequent pathogen in Pakistan, Bangladesh, and India. Vibrio cholerae was an important cause of diarrhea at those sites as well as in Mozambique.

In a follow-up 2016 study that tested a subset of these specimens with a more sensitive panel of molecular tests (quantitative polymerase chain reaction [PCR]), a higher proportion of diarrheal cases were associated with a detectable pathogen (89 versus 52 percent in the earlier study), and adenovirus 40/41 was identified as an additional common pathogen [6].

Similar findings were observed in a 2023 study including 6692 children <2 years with diarrhea in Asia and Africa (rotavirus 21 percent, ETEC 13 percent, Shigella 12 percent, and Cryptosporidium 9 percent) [7].

Norovirus was not identified as a top cause of diarrhea in this hospital-based study. In a separate community-based cohort including 199 children, norovirus was identified in approximately 25 percent of diarrheal episodes; however, given the prevalence of asymptomatic carriage and copathogens, norovirus was estimated to cause approximately 5 percent of cases [8]. Another systematic review of 130 case-control studies suggested that rotavirus, adenovirus 40/41, and Shigella had the strongest associations with diarrhea among young children [9].

Watery diarrhea

●Definition – Watery diarrhea refers to passage of ≥3 stools per day with no visible blood (table 1). Many etiologic agents of acute watery diarrhea cause symptoms that are clinically indistinguishable.

●Etiology

•Infants and young children – In infants and young children, watery diarrhea is most often due to rotavirus [10]. Cryptosporidium is also an important cause among infants, even in the absence of human immunodeficiency virus (HIV) infection [5]. (See "Clinical manifestations and diagnosis of rotavirus infection", section on 'Clinical manifestations' and "Cryptosporidiosis: Epidemiology, clinical manifestations, and diagnosis".)

•Older children – In older children, acute watery diarrhea is most often due to ETEC [11]. (See "Pathogenic Escherichia coli associated with diarrhea".)

Cholera (due to V. cholerae) is also an important cause of diarrhea in children ≥2 years of age. Cholera should be suspected if a child ≥5 years of age develops severe dehydration from acute watery diarrhea (usually with vomiting) or any patient ≥2 years of age has acute watery diarrhea when cholera is known to be occurring in the area. Children <2 years of age develop cholera rarely; in this group, the illness may be difficult to distinguish from other causes of acute watery diarrhea, especially rotavirus. (See "Cholera: Epidemiology, clinical features, and diagnosis".)

Invasive (bloody) diarrhea

●Definition – Invasive (bloody) diarrhea, or dysentery, refers to the passage of ≥3 stools per day mixed with visible blood (table 1). Bloody diarrhea usually occurs as a result of exudative inflammation of the distal small bowel and colonic mucosa in response to bacterial invasion.

●Etiology

•Shigellosis – Shigellosis is the most common etiology of invasive diarrhea among children in resource-limited settings. It is a major cause of mortality and is associated with a high incidence of bacteremia, seizures, and several other life-threatening complications. The four species are Shigella dysenteriae, Shigella flexneri, Shigella boydii, and Shigella sonnei. S. flexneri is the predominant species in children in resource-limited settings [12].

•Other etiologies – Other bacterial etiologies of invasive diarrhea include Salmonella enterica, Campylobacter spp, enterohemorrhagic E. coli, and enteroinvasive E. coli. (See related topics.)

The protozoan parasite Entamoeba histolytica is an unusual cause of invasive diarrhea in children (less than 3 percent of episodes) [1]. Amebic dysentery due to E. histolytica may be clinically indistinguishable from shigellosis and does not respond to anti-Shigella therapy. (See "Intestinal Entamoeba histolytica amebiasis".)

●Hemolytic uremic syndrome (HUS) – HUS is a rare complication associated with diarrheal illness due to Shiga toxin-producing E. coli (STEC) and S. dysenteriae; it is defined by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. (See "Overview of hemolytic uremic syndrome in children".)

Additional conditions associated with diarrhea — Systemic infections that may be associated with diarrhea include influenza, measles, dengue fever, HIV infection, malaria, and sepsis. Extraintestinal bacterial infections that may be associated with diarrhea include pneumonia, urinary tract infection, and meningitis. (See related topics.)

Intraabdominal processes such as obstruction, intussusception, or appendicitis may present with diarrhea [13-15].

Milk intolerance is a rare cause of diarrhea in resource-limited settings; this diagnosis should not be applied unless milk refeeding causes a prompt increase in stool volume, weight loss, and worsening of dehydration.

CLINICAL MANIFESTATIONS AND COMPLICATIONS

Classification of diarrhea — Diarrhea refers to the passage of loose or watery stools at least three times in a 24-hour period [1].

Acute diarrhea refers to <14 days of symptoms; it may be further classified as follows:

●Watery diarrhea – Diarrhea with no visible blood (picture 1)

●Invasive (bloody) diarrhea – Diarrhea with visible blood and/or mucus (by history or inspection) (picture 2), commonly accompanied by fever

Persistent diarrhea refers to ≥14 days of symptoms. (See "Persistent diarrhea in children in resource-limited settings".)

Dehydration and electrolyte disturbances — Dehydration is an important cause of mortality in resource-limited settings; in some cases, this may be attributable to underestimation of the initial hydration status and/or the extent of ongoing fluid loss [1].

Electrolyte disturbances may include hypokalemia, hyponatremia, and hypernatremia. (See separate topics.)

Stool potassium losses commonly result in hypokalemia. This most often manifests with muscle weakness; in more severe cases, hypokalemia may be complicated by paralytic ileus and/or arrhythmia. Among 140 patients who died following rehydration therapy in Bangladesh, hypokalemia was a proximate cause of death in 9 percent of cases [16].

Malnutrition — Recurrent diarrhea may be associated with malnutrition, which can contribute to delays in physical and cognitive development; in some cases, deficits are irreversible [15,17-19]. Clinical manifestations of severe malnutrition are described separately (table 2). (See "Malnutrition in children in resource-limited settings: Clinical assessment".)

The mortality of children with diarrhea and severe malnutrition may exceed 50 percent [15]. In severely malnourished patients, important clinical signs of dehydration may be masked by kwashiorkor and sepsis.

In settings where bodily stores of vitamin A are low, children with acute or persistent diarrhea can develop eye lesions of vitamin A deficiency and become blind (picture 3 and picture 4). This is especially a problem when diarrhea occurs during or shortly after measles or in children who are already malnourished. (See "Micronutrient deficiencies associated with protein-energy malnutrition in children", section on 'Vitamin A' and "Overview of vitamin A".)

Central nervous system (CNS) involvement — Manifestations of CNS involvement in the setting of diarrheal illness may include seizures and encephalopathy. These have been described in patients with severe disease due to Shigella and less commonly in systemic Salmonella infection [20-23].

The presence of seizures should prompt consideration of hypoglycemia, hyponatremia, and hypernatremia.

Patients with bacterial meningitis and associated diarrhea may also present with seizures.

CLINICAL ASSESSMENT — Evaluation of a child with diarrhea should begin with a detailed clinical history of the duration, frequency, and character of the diarrhea. (See 'Classification of diarrhea' above.)

Clinical assessment should include the following:

●Assessing hydration and nutrition status

•Hydration status – An approach to assessment of hydration status based on four clinical signs has been issued by the World Health Organization (WHO) (table 3) [24-26]. (See "Clinical assessment of hypovolemia (dehydration) in children".)

Following the initial assessment, ongoing fluid losses should be estimated based on the volume of emesis and stool. These assessments are essential for determining the volume, route, and pace of rehydration therapy needed.

The presence or absence of individual signs and symptoms is not a useful predictor of hydration status. As examples: a sunken anterior fontanelle is a poor predictor of dehydration in infants; a patient who sheds tears may still be dehydrated; and hypotension is a late finding in children with dehydration (and may be absent even in severe dehydration) [27].

•Nutritional status – The approach to clinical assessment for malnutrition is outlined separately (table 2). (See "Malnutrition in children in resource-limited settings: Clinical assessment".)

Children with acute diarrhea and malnutrition are at increased risk for fluid overload and heart failure during rehydration; therefore, such children require an individualized approach to rehydration and nutritional repletion. (See 'Presence of severe malnutrition' below.)

●Physical examination – Children with diarrhea should undergo a complete physical examination with careful attention to the following (see "The pediatric physical examination: General principles and standard measurements"):

•Temperature – Fever is common in the setting of diarrheal illness; however, the presence of fever or hypothermia should also prompt consideration of comorbid illnesses, such as pneumonia, sepsis, or malaria (in areas where endemic).

•Respiratory rate – The WHO uses the following definitions for tachypnea [28]:

-Infants <2 months of age: ≥60 breaths/minute

-Infants 2 to 12 months of age: ≥50 breaths/minute

-Children 1 to 5 years of age: ≥40 breaths/minute

-Children ≥5 years of age: ≥20 breaths/minute (≥30 breaths/minute is a more specific threshold)

Tachypnea may occur in patients with metabolic acidosis associated with dehydration, as well as in the setting of pneumonia [29]. (See 'Role of antibiotics' below.)

•Abdomen – Presence of abdominal pain should prompt consideration for an additional intrabdominal process, such as obstruction, intussusception, or appendicitis. (See "Emergency evaluation of the child with acute abdominal pain".)

•Central nervous system (CNS) – Moderate dehydration may be associated with irritability; severe dehydration can lead to lethargy and coma. Other manifestations of CNS involvement in the setting of diarrheal illness include seizures and encephalopathy. (See 'Central nervous system (CNS) involvement' above.)

Patients may present with bacterial meningitis and associated diarrhea; in infants with meningitis, meningeal signs may be absent. Therefore, the presence of any abnormal neurologic findings should prompt consideration of meningitis. (See "Bacterial meningitis in children older than one month: Clinical features and diagnosis", section on 'Clinical features'.)

•Eye exam – Patients should be examined for signs of vitamin A deficiency; these include corneal clouding (picture 3) and conjunctival lesions (Bitot spot) (picture 4). (See 'Malnutrition' above.)

DIAGNOSTIC EVALUATION — The approach to diagnostic evaluation should be guided by clinical circumstances, as outlined below.

●Watery diarrhea – It is important to distinguish cholera from other causes of acute watery diarrhea because patients with severe cholera may have more rapid fluid losses and typically benefit from antibiotic therapy. (See 'Watery diarrhea' above and "Cholera: Epidemiology, clinical features, and diagnosis".)

A definitive diagnosis of cholera is established by stool culture; supportive diagnostic tools include darkfield microscopy for detection of motile vibrios (which appear as “shooting stars”) or a stool dipstick.

In the absence of diagnostic tools, patients with a short history (usually <24 hours) of vomiting and voluminous watery diarrhea with a characteristic rice-water appearance (picture 1), especially in the setting of an outbreak, may be presumptively diagnosed with cholera based on clinical suspicion.

●Invasive (bloody) diarrhea – For patients with invasive (bloody) diarrhea, stool culture is warranted if feasible.

For patients who do not respond to antibiotic therapy (see 'Role of antibiotics' below), evaluation for E. histolytica is warranted via stool microscopy for the detection of trophozoites containing red blood cells (picture 5). (See "Intestinal Entamoeba histolytica amebiasis".)

●Additional manifestations

•Fever – For patients with fever in settings where malaria is endemic, further diagnostic evaluation is warranted. (See "Malaria: Clinical manifestations and diagnosis in nonpregnant adults and children".)

•Abdominal pain – For patients with watery diarrhea and abdominal pain who are not responsive to initial rehydration, imaging studies are warranted. (See "Emergency evaluation of the child with acute abdominal pain".)

•Respiratory distress – For patients with respiratory distress, reassessment following initial rehydration is warranted. For children with tachypnea in addition to cough and/or chest retractions, we favor presumptive treatment for pneumonia prior to the completion of rehydration. (See 'Role of antibiotics' below.)

A chest radiograph is warranted for the evaluation of pneumonia, particularly in severely malnourished and dehydrated patients [30-32]. Further evaluation of children with respiratory distress is discussed separately. (See "Acute respiratory distress in children: Emergency evaluation and initial stabilization".)

•Neurologic symptoms – For patients with neurologic symptoms, glucose and electrolyte assessments should be pursued. The approach to the evaluation of meningitis in children is discussed separately. (See "Bacterial meningitis in children older than one month: Clinical features and diagnosis".)

MANAGEMENT

Absence of severe malnutrition — In the absence of severe malnutrition (see 'Clinical assessment' above), treatment of children with acute diarrhea consists of correcting fluid and electrolyte losses, administering appropriate nutrition, and managing associated comorbid conditions [1]. Antibiotic therapy is warranted in some circumstances, as outlined below.

Fluid and electrolytes — Rehydration therapy is critical for management of diarrhea. The goal of replacement therapy is to replenish deficits in water and electrolytes lost. (See "Shock in children in resource-limited settings: Initial management" and "Treatment of hypovolemia (dehydration) in children in resource-abundant settings".)

●Phases of treatment – Fluid management consists of two phases: replacement and maintenance.

•Replacement – Treatment begins with the replacement phase, which continues until all signs and symptoms of volume depletion have resolved and the patient has urinated; ideally, this is achieved during the first four hours of treatment.

•Maintenance – The maintenance phase counters ongoing losses of water and electrolytes; this phase continues until diarrhea and other signs and symptoms of illness have resolved.

●Clinical approach – The approach to fluid and electrolyte management depends on the degree of dehydration. The WHO provides definitions and treatment guidelines along a continuum that includes "no dehydration" (Plan A), "some dehydration" (Plan B), and "severe dehydration" (Plan C) [33]:

•No signs of dehydration (Plan A) – This category includes children with <5 percent dehydration (table 3).

-Site of care – Patients with no signs of dehydration do not require replacement therapy and can begin maintenance therapy. Hospital admission is not usually required; patients may be sent home after a brief period of observation to verify that they are tolerating oral maintenance fluids.

-Maintenance fluid – Ideally, oral rehydration solution (ORS), a mixture of water, salts, and glucose, should be administered to counter ongoing fluid and electrolyte losses (table 4). In general, children ≤2 years old should receive approximately 50 to 100 mL of ORS for each episode of diarrhea or vomiting; children >2 years old should receive 100 to 200 mL of ORS for each episode. (See "Oral rehydration therapy".)

-Supplemental fluid – If the stool output is modest (eg, no more than three loose stools/day or under 10 g/kg of stool per day), ORS may not be necessary; ongoing feeding along with supplemental fluids (table 5) may be sufficient.

•Some dehydration (Plan B) – This category includes children with 5 to 10 percent dehydration (table 3).

-Site of care – Patients with some dehydration warrant replacement therapy with ORS in a supervised setting.

-Replacement fluid – The replacement fluid volume should be guided by patient age and weight, as outlined in the table (table 6).

If ongoing stool losses are profound, these losses may be added to the initial replacement fluid given over the initial four hours of treatment. Stool output may be measured by collecting stool using a cholera cot (picture 6). Alternatively, stool output may be estimated at 10 to 20 mL/kg of body weight for each diarrheal stool.

Replacement fluids should be continued under supervision until there are no signs of dehydration and the patient has urinated. This may require more fluid volume than initially estimated; frequent reassessment of hydration status is essential.

-Maintenance fluid – Once dehydration has been corrected, the administration of maintenance fluid (ideally ORS) to counter ongoing losses can be managed as for patients with no signs of dehydration (outlined above).

Children with profound ongoing stool losses termed high purging (≥15 mL/kg per hour; such as seen in cholera) or with persistent vomiting (≥3 episodes per hour) may fail repeated attempts at oral rehydration or progress to severe dehydration; this occurs in approximately 3 to 5 percent of patients [34]. Such patients require intravenous (IV) correction for severe dehydration, as outlined below.

•Severe dehydration (Plan C) – This category includes children with >10 percent dehydration (table 3). According to the WHO, severe dehydration is an emergency sign that essentially requires treatment with IV fluids, even if the patient does not meet the WHO clinical or systolic blood pressure criteria for shock (table 7 and table 8).

The WHO plan C provides recommendations for fluid repletion of severe dehydration for these patients that vary by the degree of anemia and malnutrition as shown in the algorithm (algorithm 1) and discussed separately. (See "Shock in children in resource-limited settings: Initial management", section on 'Severe dehydration (The WHO plan C)'.)

The WHO plan C also provides guidance on fluid management and transfer to a higher level of care for children with severe dehydration in settings where IV or intraosseous access is not available (algorithm 2).

Role of antibiotics — Use of antibiotics should be guided by clinical circumstances, as outlined below.

●Patients with watery diarrhea – For patients with known or suspected cholera in the setting of moderate to severe volume depletion, and for patients with known or suspected cholera in the setting of an epidemic, antibiotic therapy is warranted (table 9). (See "Cholera: Epidemiology, clinical features, and diagnosis".)

For patients with watery diarrhea in the absence of the above factors, there is no role for routine antibiotic therapy.

The above approach is supported by a randomized trial including more than 8000 children in a resource-limited setting. Patients were randomly assigned to receive azithromycin or placebo for three days; antibiotic treatment did not confer a survival benefit from empiric azithromycin [35]. There was a small reduction in growth faltering among those who received antibiotics, although the magnitude was not likely to be clinically significant.

●Patients with invasive (bloody) diarrhea

•Empiric treatment for Shigella infection – For patients with invasive diarrhea, empiric antibiotic therapy with activity against Shigella species is warranted (table 10).

Antimicrobial treatment of Shigella infection reduces the duration of fever and diarrhea, reduces the duration of bacterial shedding, and may reduce the risk of life-threatening complications of infection such as bacteremia and encephalopathy [20,21,36]. (See "Shigella infection: Treatment and prevention in children", section on 'Antibiotic therapy'.)

Antibiotic therapy should be tailored to culture and susceptibility data, if available.

•Patients with persistent symptoms – For patients with invasive diarrhea that does not remit within two days of starting empiric antibiotic therapy, switching to an alternative antimicrobial agent is warranted (table 10).

For patients with persistent symptoms after two days of treatment with an alternative antibiotic agent, evaluation for amebiasis (an unusual cause of invasive diarrhea) is warranted. (See 'Infectious causes' above and 'Diagnostic evaluation' above.)

•Patients with amebiasis – Treatment of amebiasis consists of metronidazole (35 to 50 mg/kg per day in three divided doses for 7 to 10 days in children; maximum 750 mg orally, three times daily). (See "Intestinal Entamoeba histolytica amebiasis".)

●Patients with severe acute malnutrition – Patients with diarrhea and severe acute malnutrition should be treated with empiric broad-spectrum antibiotics [1,37]. This is discussed further separately. (See "Management of complicated severe acute malnutrition in children in resource-limited settings", section on 'Empiric antibiotics' and "Management of uncomplicated severe acute malnutrition in children in resource-limited settings", section on 'Antibiotics'.)

●Patients with tachypnea as well as cough and/or chest retractions – For children with tachypnea in addition to cough and/or chest retractions, we favor presumptive treatment for pneumonia prior to completion of rehydration [29]. For children with tachypnea in the absence of other respiratory symptoms, we reassess the need for antibiotic treatment following initial rehydration.

Nutrition — For patients with acute diarrhea in the absence of malnutrition, sufficient feeding should be encouraged (during as well as after the diarrheal episode) to prevent the development of malnutrition and chronic enteropathy. The approach for patients with severe malnutrition is discussed separately. (See 'Presence of severe malnutrition' below.)

Infants with diarrhea should be encouraged to breastfeed as much as possible [1]. Infants who are not breastfed should be encouraged to continue to take undiluted formula at least every three hours.

Children with diarrhea should be encouraged to take solid foods immediately after initial dehydration is corrected [38]. Delaying the initiation of a nutrient-rich diet may increase the risk of malnutrition.

As long as diarrhea persists, foods high in energy content and micronutrients should be offered at frequent intervals (at least six meals a day). After the diarrhea resolves, at least one extra meal per day should be continued for a minimum of two weeks, or until the patient regains normal weight-for-height [1].

Vitamins and minerals

●Zinc – We are in agreement with the WHO, which recommends zinc supplementation for children with diarrhea [1]. We administer zinc supplementation to children 6 months to 5 years of age at a dose of 10 mg/day for 14 days.

Zinc supplementation is supported by a 2016 meta-analysis including 33 trials and more than 10,000 children ages one month to five years with diarrhea. Among 2581 children >6 months of age in nine trials, zinc supplementation shortened the duration of diarrhea by approximately half a day (mean duration -11.46 hours, 95% CI -19.72 to -3.19) [39]. Among 419 children with signs of malnutrition in five trials, zinc supplementation shortened the duration of diarrhea by around a day (mean duration 26.39 hours, 95% CI -36.54 to -16.23).

Our dosing approach differs from that of the WHO, given the association of zinc supplementation with vomiting [39,40]. One randomized trial including more than 4500 children (age 6 to 59 months) found that a daily zinc dose of 10 mg or 5 mg was associated with a lower risk of vomiting than 20 mg (relative risk of vomiting 0.81 [97.5% CI 0.57-0.96] for 10 mg and 0.71 [97.5% CI 0.59-0.86] for 5 mg) and comparable efficacy for the treatment of diarrhea [41]. Based on these findings, we favor a zinc dose of 10 mg for 14 days, pending further guidance from the WHO.

Issues related to zinc deficiency and supplementation are discussed further separately. (See "Zinc deficiency and supplementation in children".)

●Vitamin A – Administration of vitamin A is warranted for patients with acute diarrhea who have signs and symptoms of vitamin A deficiency (such as xerophthalmia, keratitis, keratoconjunctivitis, corneal ulceration, or Bitot spots). (See 'Clinical assessment' above.)

Vitamin A dosing is outlined separately. (See "Overview of vitamin A", section on 'Replacement'.)

In addition, routine vitamin A supplementation has been associated with reducing morbidity and mortality among children in resource-limited settings. (See "Overview of vitamin A", section on 'Deficiency'.)

Limited role for other interventions — The mainstays of treatment for children with acute diarrhea in resource-limited settings include the interventions outlined above. No additional therapies have well established benefits, and some are potentially harmful.

We do not favor routine use of antimotility agents or antiemetics in children with acute diarrhea. Antimotility agents (such as loperamide, diphenoxylate-atropine, and tincture of opium) prolong some bacterial infections and have been associated with rare cases of fatal paralytic ileus [42]. Antiemetics (such as ondansetron, metoclopramide, and promethazine) have sedating effects that can interfere with rehydration and may cause extrapyramidal reactions and respiratory depression [1].

Presence of severe malnutrition — Children with acute diarrhea and severe malnutrition require an individualized approach to rehydration and nutritional repletion. These issues are discussed further separately. (See "Management of complicated severe acute malnutrition in children in resource-limited settings", section on 'Dehydration' and "Shock in children in resource-limited settings: Initial management", section on 'Severe dehydration (The WHO plan C)'.)

PREVENTION — Interventions for the prevention of diarrhea include [1]:

●Immunization – Vaccination against measles, rotavirus, and cholera is an important tool for the prevention of diarrhea. (See "Measles: Clinical manifestations, diagnosis, treatment, and prevention", section on 'Measles, mumps, and rubella vaccination' and "Rotavirus vaccines for infants" and "Cholera: Epidemiology, clinical features, and diagnosis".)

●Breastfeeding – The World Health Organization (WHO) recommends exclusive breastfeeding until age six months, followed by continued breastfeeding with complementary foods until two years of age.

●Hygiene – Use of clean water, food safety practices, handwashing, and latrines.

●Nutrition – Optimizing nutritional status is important for the prevention of poor outcomes related to diarrheal illness. In areas where vitamin A deficiency is common, routine vitamin A supplementation has been associated with reducing morbidity and mortality. (See "Overview of vitamin A", section on 'Deficiency'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Acute diarrhea in children".)

SUMMARY AND RECOMMENDATIONS

●Classification and etiology – Diarrhea refers to the passage of loose or watery stools at least three times in a 24-hour period. Acute diarrhea refers to <14 days of symptoms. Most cases of acute diarrhea in resource-limited settings are caused by infectious gastroenteritis; patients may present with watery diarrhea or invasive (bloody) diarrhea. The microbial etiology is summarized in the table (table 1). (See 'Etiology' above and 'Classification of diarrhea' above.)

●Clinical manifestations and complications – Clinical manifestations and complications of acute diarrhea include dehydration, electrolyte disturbances, and malnutrition. Manifestations of central nervous system (CNS) involvement may include seizures and encephalopathy. (See 'Clinical manifestations and complications' above.)

●Clinical assessment – Clinical evaluation should include assessment of hydration (table 3) and nutrition status (table 2), as well as a complete physical examination. (See 'Clinical assessment' above.)

●Diagnostic evaluation – The approach to diagnostic evaluation should be guided by clinical circumstances (see 'Diagnostic evaluation' above):

•Watery diarrhea – It is important to distinguish cholera from other causes of acute watery diarrhea since patients with severe cholera may have more rapid fluid losses and typically benefit from antibiotic therapy. A definitive diagnosis of cholera is established by stool culture; supportive diagnostic tools include darkfield microscopy (for the detection of motile vibrios) or a stool dipstick.

In the absence of diagnostic tools, patients with a short history (usually <24 hours) of vomiting and voluminous watery diarrhea with characteristic rice-water appearance (especially in the setting of an outbreak) may be presumptively diagnosed with cholera based on clinical suspicion.

•Invasive (bloody) diarrhea – For patients with invasive diarrhea, stool culture is warranted if feasible.

●Management in absence of severe malnutrition – In general, management of children with acute diarrhea consists of correcting fluid and electrolyte losses, administering appropriate nutrition, and assessing the need for antibiotics. (See 'Management' above.)

•Fluid and electrolytes – The approach to fluid and electrolyte management depends on the degree of dehydration (table 3) (see 'Fluid and electrolytes' above):

-No signs of dehydration (<5 percent dehydration, Plan A) – Management consists of maintenance therapy with oral rehydration solution (ORS) (table 4). In general, children ≤2 years of age should receive approximately 50 to 100 mL of ORS for each episode of diarrhea or vomiting; children >2 years should receive 100 to 200 mL of ORS for each episode.

-Some dehydration (5 to 10 percent, Plan B) – Management consists of replacement therapy with ORS (guided by age and weight (table 6)) in a supervised setting. Stool output may be collected or estimated (10 to 20 mL/kg of body weight for each diarrheal stool). Replacement fluids should be continued under supervision until there are no signs of dehydration and the patient has urinated. This may require more fluid volume than initially estimated; frequent reassessment of hydration status is essential.

-Severe dehydration (>10 percent, Plan C) – Management consists of urgent treatment with intravenous (IV) isotonic crystalloid fluids in a hospital setting; fluid therapy varies by the degree of anemia and malnutrition as shown in the algorithm (algorithm 1) and discussed separately. (See "Shock in children in resource-limited settings: Initial management", section on 'Severe dehydration (The WHO plan C)'.).

The WHO plan C also provides guidance on fluid management and transfer to a higher level of care for children with severe dehydration in settings where IV or intraosseous access is not available (algorithm 2).

-Patients with seizures – If seizures are present (and hypoglycemia is suspected), a rapid bolus of IV glucose should be given, followed by addition of 5% glucose to the IV fluid.

•Role of antibiotics (see 'Role of antibiotics' above):

-Watery diarrhea – For patients with known or suspected cholera in the setting of moderate to severe volume depletion, and for patients with known or suspected cholera in the setting of an epidemic, antibiotic therapy is warranted; selection and dosing are summarized in the table (table 9). Issues related to cholera are discussed separately. (See "Cholera: Epidemiology, clinical features, and diagnosis".)

For patients with watery diarrhea in the absence of the above factors, we suggest not treating with antibiotics (Grade 2B).

-Invasive (bloody) diarrhea – For patients with invasive diarrhea, antibiotic therapy with activity against Shigella species is warranted; selection and dosing are summarized in the table (table 10). Issues related to Shigella infection are discussed separately. (See "Shigella infection: Treatment and prevention in children".)

•Nutrition, vitamins, and minerals – For patients with acute diarrhea in the absence of malnutrition, sufficient feeding should be encouraged. (See 'Nutrition' above and 'Vitamins and minerals' above.)

-Zinc – For children six months to five years of age with acute diarrhea, we suggest zinc administration (Grade 2B); dosing is outlined above.

-Vitamin A – Children with signs of vitamin A deficiency require vitamin A administration. Vitamin A dosing is outlined separately. (See "Overview of vitamin A", section on 'Replacement'.)

●Management in presence of severe malnutrition – Management of children with acute diarrhea and severe malnutrition is discussed further separately. (See "Management of complicated severe acute malnutrition in children in resource-limited settings", section on 'Dehydration' and "Persistent diarrhea in children in resource-limited settings", section on 'Rehydration'.)

●Prevention – Tools for prevention of diarrhea include immunization against vaccine-preventable diseases, breastfeeding, and attention to good hygiene practices. (See 'Prevention' above.)