Acute Gastroenteritis in Children(AGE)

Acute Gastroenteritis in Children(AGE) 

CONTENTS

Acute gastroenteritis in children

Epidemiology 

Etiology 

Pathogenesis

Risk factors

Clinical manifestations

Complications

Diagnosis 

Differential diagnosis 

Transmission 

Prevention 

Treatment 

Acute Gastroenteritis

Gastroenteritis -infections of the gastrointestinal  tract caused by bacterial, viral, or parasitic

The most common digestive disorder among children 

The most common manifestations are diarrhea and vomiting,  can also be associated with  abdominal pain and fever.

Epidemiology

Account for 18% of childhood deaths, and 1.5 million deaths per year globally

 The second most common cause of child deaths worldwide. 

WHO and UNICEF estimate 2.5 billion episodes of diarrhea  annually in children <5 yr of age in developing countries

More than 80% of the episodes occurring in Africa and South Asia . 

Global mortality may be declining, but the overall incidence of diarrhea remains unchanged at about 3.6 episodes per child-year

Rates of hospitalization and deaths due to Shigella infections account for almost 160,000 deaths annually. 

Enterotoxigenic Escherichia coli (ETEC) may be responsible for 300,000-500,000 deaths among children <5 yr annually. 

Rotavirus infections  account for 527,000 deaths annually or 29% of all deaths due to diarrhea among children <5 yr of age. 

Six countries (India, Nigeria, Congo, Ethiopia, China, and Pakistan) accounted for >50% of deaths due to rotavirus disease.

The decline in diarrheal mortality, despite the lack of significant changes in incidence, is the result of: 

      Preventive rotavirus vaccination 

      Improved case management and

      Improved nutrition of infants and children  

Early and repeated episodes of childhood diarrhea during  critical development,  when associated with malnutrition, co-infections, and anemia, can have long-term effects on linear growth,  physical and cognitive functions

Etiology of gastroenteritis in children 

Gastroenteritis is usually caused by 

◆Viruses (most common cause )

◆Bacteria  or 

◆Parasitic  

◆Rare causes 

◆Chemical toxins 

◆Drugs 

Viruses

Rotaviruses (most common worldwide)

Noroviruses (most common in USA)

Bacteria

◆E.coli

◆Shigella

◆Salmonella 

◆Staphylococci(causing staphylococcal food poisoning)

◆Campylobacter

◆Clostridium difficile

Parasites

◆Giardia 

◆Entamoeba histolytica

Pathogenesis of Infectious Diarrhea 

Pathogenesis and severity of bacterial disease depend on whether organisms have preformed 

Toxins (S. aureus, Bacillus cereus), 

produce secretory (cholera, E. coli, Salmonella, Shigella) or

 Cytotoxic (Shigella, S. aureus, Vibrio parahemolyticus, C. difficile, E. coli, C. jejuni) toxins or are invasive and on whether they replicate in food. 

COMPARISON OF THREE TYPES OF ENTERIC INFECTION

PATHOGENIS

Enteropathogens elicit: 

Noninflammatory diarrhea through enterotoxin production by some bacteria, destruction of villus (surface) cells by viruses, adherence by parasites, and adherence and/or translocation by bacteria. 

Inflammatory diarrhea is usually caused by bacteria that directly invade the intestine or produce cytotoxins   

Some viruses, such as rotavirus, target the microvillus tips of the enterocytes 

Bacterial enterotoxins can selectively activate enterocyte intracellular signal transduction and can also affect cytoskeletal rearrangements with subsequent alterations in the water and electrolyte fluxes across enterocytes.

 In toxigenic diarrhea enterotoxin produced by Vibrio cholerae, increased mucosal levels of cAMP inhibit electroneutral NaCl absorption but have no effect on glucose-stimulated Na+ absorption.

ETEC colonizes and adheres to enterocytes of the small bowel via its surface fimbriae (pili) and induces hypersecretion of fluids and electrolytes into the small intestine through toxins

 

Shigella spp. cause gastroenteritis via a superficial invasion of colonic mucosa and invade through M cells located over Peyer patches.

 After phagocytosis, a series of events occurs:

Apoptosis of macrophages, 

Multiplication and spread of bacteria into adjacent cells, 

Release of inflammatory mediators , 

Transmigration of neutrophils into the lumen 

Neutrophil necrosis and degranulation, 

Further breach of the epithelial barrier, and mucosal destruction 

Risk Factors for Gastroenteritis

Environmental contamination and increased exposure to enteropathogens. 

young age, immunodeficiency, measles, 

Malnutrition, and lack of exclusive or predominant breast-feeding. 

In children with vitamin A deficiency, the risk of dying from diarrhea, measles, and malaria is increased by 20-24%. 

Zinc deficiency is estimated to increase the risk of mortality from diarrhea, pneumonia, and malaria by 13-21%

Majority of cases of diarrhea resolve within the 1st wk of the illness

 A smaller proportion of diarrheal  fail to resolve and persist for >2 wk.

 Persistent diarrhea is defined as episodes that began acutely but last for ≥14 days.

Account for 3-20% of all diarrheal episodes in children <5 yr of age and up to 50% of all diarrhea-related deaths. 

Many children in developing countries have frequent episodes of acute diarrhea and result in: 

  Persistent diarrhea, 

  Protein-calorie malnutrition, and 

  Secondary infections 

Clinical Manifestation  

 depends on: 

 Infecting pathogen and the dose or inoculum 

 Development of complications (e.g., dehydration and electrolyte imbalance) and 

The nature of the infecting pathogen 

Ingestion of preformed toxins (e.g., those of S. aureus) is associated with the rapid onset of nausea and vomiting within 6 hr, with possible fever, abdominal cramps, and diarrhea within 8-72 hr. 

Watery diarrhea and abdominal cramps after an 8-16 hr  IP- enterotoxin-producing C. perfringens and B. cereus. 

Abdominal cramps and watery diarrhea after a 16-48 hr IP-  viruses, several enterotoxin-producing bacteria, Cryptosporidium, and Cyclospora  

Salmonella, Shigella, C. jejuni, Yersinia enterocolitica, enteroinvasive or hemorrhagic  E. coli –bloody diarrhea , fecal leukocytes, abdominal cramps, tenesmus, and fever 

Organisms associated with dysentery or hemorrhagic diarrhea can also cause watery diarrhea alone 

COMPLICATIONS

Most of the complications are related to delays in diagnosis and   therapy.

 Dehydration   can be life-threatening in infants and young children

Inappropriate therapy can lead to persitant diarrhea,  malnutrition and  other complications 

 These complication are more common In developing countries and HIV-infected populations.

Specific pathogens are associated with extraintestinal manifestations and complications. 

SHOCK

Shock especially hypovolemic shock can be a complication of Gastroentritis 

As a result of excessive fluid loss due to diarrhea or vomiting hypovolemic shock can occur b/c there is insufficient fluid inside the blood vessels

DIAGNOSIS

The diagnosis of gastroenteritis is based on 

Clinical recognition, 

Evaluation of its severity by rapid assessment and

Confirmation by  laboratory, if indicated

The most common manifestation of GI tract infection in children is diarrhea, abdominal cramps, and vomiting. 

Systemic manifestations are varied and associated with a variety of causes. 

The evaluation of a child with acute diarrhea includes: 

    • Assess the degree of dehydration and acidosis and provide rapid resuscitation and rehydration • Obtain appropriate contact, travel, or exposure history• Clinically determine the etiology of diarrhea for prompt antibiotic therapy, if indicated. 

Although nausea and vomiting are nonspecific symptoms, they indicate infection in the upper intestine

Fever is common in patients with inflammatory diarrhea

Abdominal pain and tenesmus - large intestine and rectum

SYMPTOMS ASSOCIATED WITH DEHYDRATION

SUMMARY OF TREATMENT BASED ON DEGREE OF DEHYDRATION

DIAGNOSIS

Microscopic examination of the stool and cultures can yield important information on the etiology of diarrhea. 

◆Stool cultures should be obtained  from children with :

◆Bloody diarrhea,

 ◆Fecal leukocytes, 

◆In outbreaks 

◆In immunosuppressed  

◆Appendicitis

◆Inflammatory bowel disease 

◆Pancreatic insufficiency

TRANSMISSION

Feco-oral transmission

Food borne 

TREATMENT

The broad principles of management of acute gastroenteritis in children include: 

Rehydration therapy(oral or IV fluid)

Enteral feeding and diet selection, 

Zinc supplementation, and 

Antibiotics

Oral Rehydration Therapy

Dehydration must be evaluated rapidly and corrected in 4-6 hr according to the degree of dehydration 

The low-osmolality WHO oral rehydration solution (ORS) containing 75 mEq of sodium and 75 mmol of glucose per liter, with total osmolarity of 245 mOsm per liter, is more effective 

Enteral Feeding and Diet Selection 

Continued  feeding in diarrhea aids in recovery from the episode, and a continued age-appropriate diet after rehydration is the norm

Breast-feeding or nondiluted regular formula should be resumed as soon as possible

Zinc Supplementation 

Zinc leads to reduced duration and severity of diarrhea and  recurrence. 

WHO and UNICEF recommend that all children with acute diarrhea in at-risk areas should receive oral zinc  for 10-14 days during and 

10 mg/day for infants <6 mo of age and 20 mg/day for those >6 mo

Antibiotic Therapy 

Timely antibiotic therapy in select cases of diarrhea can reduce the duration and severity of diarrhea and prevent complications 

PREVENTIVE STRATEGIES

Promotion of Exclusive Breast-feeding

Improved Complementary Feeding Practices

Rotavirus Immunization 

Improved Water and Sanitary Facilities and Promotion of Personal and Domestic Hygiene 

Improved Case Management of Diarrhea 

Promotion of Exclusive Breast-feeding 

 Exclusive breast-feeding for the first 6 months of life is widely regarded as one of the most effective interventions to reduce the risk of premature childhood mortality and the potential to prevent 13% of all deaths of children <5 yr of age.

Improved Complementary Feeding Practices 

 Complementary foods should be introduced at 6 mo of age, and breast-feeding should continue for up to 1 yr (longer period for developing countries). 

 Vitamin A supplementation reduces all-cause childhood mortality by 21% and diarrhea-specific mortality by 31% (95% CI, 17-42%).

Rotavirus Immunization 

In 1998, a quadrivalent Rhesus rotavirus-derived vaccine was licensed in the United States but subsequently withdrawn due to an increased risk of intussusception. 

Subsequent development and testing of newer rotavirus vaccines have led to their introduction in most developed countries and approval by the WHO in 2009 for widespread use in developing countries. 

The introduction of these vaccines is associated with a significant reduction in severe diarrhea and mortality.

Improved Water and Sanitary Facilities and Promotion of Personal and Domestic Hygiene 

Strikingly, an estimated 88% of all diarrheal deaths worldwide can be attributed to unsafe water, inadequate sanitation, and poor hygiene. 

Routine handwashing with plain soap in the home can reduce the incidence of diarrhea in all environments. 

Improved Case Management of Diarrhea 

 The WHO/UNICEF recommendations to use

 low-osmolality ORS and zinc supplementation 

 selective and appropriate use of antibiotics 

A recent estimate indicated that 22% of all deaths of children <5 yr of age could be prevented by optimal use of ORS, zinc supplements, and antibiotics for dysentery