Acute gastroenteritis( Acute diarrhea)
4th medical class
Oct/2015
Prof: Yusra AR Mahmood
Ref. Nelson textbook for pediatrics,19th. Edt.
Objectives:
 Define the concept of gastroenteritis
 Identify the etiology of GE
 Explain the pathogenesis of GE
 Identify the clinical features of GE
 Assess the degree of dehydrations
 Enumerate the complications following GE
 Define the concept of ORT
 Outline the treatment of GE
The term gastroenteritis denotes infections of the gastrointestinal tract
caused by bacterial, viral, or parasitic pathogens
Epidemiology
The WHO suspects that there are >700 million episodes of diarrhea
annually in children <5 yr of age in developing countries.
While global mortality may be declining, but the overall incidence of
diarrhea remains unchanged at about 3.2 episodes /child /year
Morbidity:
Early and repeated episodes of childhood diarrhea during periods of critical
development, especially when associated with malnutrition, co-infections,
and anemia may have long-term effects on
 linear growth,
 physical and
 cognitive functions.
ETIOLOGY of DIARRHEA
Gastroenteritis is due to infection acquired through :
the feco-oral route or by ingestion of contaminated food or water.
Enteropathogens that are infectious in a small inoculum
 Shigella, Escherichia coli,
 noroviruses, rotavirus,
1




Giardia lamblia,
Cryptosporidium parvum,
Entamoeba histolytica
cholera
The most common pathogens producing diarrhea in developing countries
 Salmonella,
 Shigella, and,
 E.coli
 Cl.difficile is linked to antibiotic associated diarrhea and
pseudomemberanous enterocolitis
Pathogenesis of infectious diarrhea
Pathogenesis and severity of bacterial disease depend on whether organisms
have preformed toxins Staphylococcus aureus , or are invasive
Enteropathogens can lead to either an inflammatory or noninflammatory
response in the intestinal mucosa.
Enteropathogens elicit noninflammatory diarrhea through




enterotoxin production by some bacteria,
destruction of villous (surface) cells by viruses,
Adherence by parasites, and
adherence by bacteria.
Inflammatory diarrhea is usually caused by bacteria that directly invade
the intestine or produce cytotoxins with consequent fluid, protein and
cells (erythrocytes leukocytes) that enter the intestinal lumen
Risk Factors for Gastroenteritis include:
 environmental contamination
 young age
 immune deficiency
 measles,
 Lack of breast-feeding.
 Malnutrition.
2
 micronutrient malnutrition;
o vitamin A deficiency,
o Zinc deficiency
Clinical manifestations of diarrhea
Most of them are related to the infecting pathogen and the dose/inoculum
or complications (such as dehydration and electrolyte imbalance)
Usually the ingestion of performed toxins (such as those of Staphylcoccus
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 8-16hr incubation period are
associated with enterotoxin -producing Clostridium perfringens and
Bacillus cereus
noroviruses,
several enterotoxin-producing bacteria,
Cryptosporidium,
and Cyclospora.
after a 16-48 hr incubation period
Abdominal cramps
and watery diarrhea
Several organisms, including
Salmonella,
Shigella,
Campylobacter jejuni,
Yersinia enterocolitica,
enteroinvasive E. coli, and,
Vibrio parahaemolyticus,
produce diarrhea + blood + fecal leukocytes
abdominal cramps, tenesmus, and fever; Bacterial dysentery
3
Shigella and also Shiga toxin-producing E.coli (E.coli 0157:H7). after a
72-120 hr incubation period Bloody diarrhea and abdominal cramps
Complications






Dehydration with associated complications
prolongation of the diarrheal episodes,
with consequent malnutrition and
complications such as secondary infections
and micronutrient deficiencies (iron, zinc).
extra-intestinal manifestations and complications.
 Reactive arthritis Salmonella,Shigella ,Yesinia,
Campylobacter,Cryptosporidium, Cl.difficile
 Guillain-Barrie Campylobacter
 Glomerulonephritis Shigella ,Campylobacter Yersinia
 IgA nephropathy Compylobacter
 Erythema nodosum Yersinia, Salmonella, Campylobacter
 Hemolytic uremic syndrome , Shigella dysentrie1, E.coli
0157:H7,
 Hemolytic anemia Campylobacter Yersinia
 Focal infection due to systemic spread of bacterial pathogens,
 Valvovaginitis , UTI,
 infective endocarditis,
 Osteomyelitis, meningitis ,
 pneumonia, hepatitis
 Peritonitis, soft tissue infection,
 infected thrombophlebitis
Diagnosis
The diagnosis of gastroenteritis is based on
1) clinical recognition,
2) and evaluation of its severity by rapid assessment
3) And laboratory investigations if indicated.
1- Clinical manifestations 0f diarrhea
4
The most common manifestations:diarrhea, abdominal cramps, and
vomiting.
Systemic manifestations are varied according to the causes
Obtain appropriate history: contact or exposure with similar symptoms,
contaminated food or water, child care center attendance, recent travel to a
diarrhea-endemic area, use of Antimicrobial therapy.
Clinical manifestations determine the etiology of diarrhea:
nausea and vomiting indicate infection in the upper intestine
fever is common in patients with Inflammatory diarrhea.
Severe abdominal pain & tenesmus are indicative of involvement large
intestine and rectum.
Features such as : nausea and vomiting ,absent or low-grade fever ,mild
to moderate periumbilical pain ,watery diarrhea are indicative of small
intestinal Involvement and also reduce the likelihood of Serious bacterial
infection.
2- The evaluation of a child with acute diarrhea includes:
Assess the degree of dehydration and Acidosis
provide rapid resuscitation and rehydration with oral or intravenous fluid
as required
Symptoms Associated With Dehydration
Stool Examination for mucus, blood, and leukocytes.
Fecal leukocytes are indicative of bacterial invasion of colonic mucosa,
In endemic areas, examination for parasites causing diarrhea, such as G.
lamblia and E. histolytica.
Stool cultures :should be obtained as early in the course of disease as
possible ; Indications:
bloody diarrhea +fecal leukocytes
outbreaks with suspected (HUS)
in immunosuppressed children with diarrhea
In most previously healthy children with uncomplicated watery diarrhea,
NO laboratory evaluation is needed except for epidemiologic purposes.
5
3- Treatment
The broad principles of management of acute gastroenteritis in children
include:
1) rehydration therapy, ORS , IV
2) enteral feeding
3) diet selection
4) Zinc supplementation and
5) Probiotics.
1-ORS
I- Degree of dehydration : Minimal or No dehydration
Replacement therapy : not applicable.
Replacement of losses :
<10 kg ------- 60 -120 ml ORS /motion or vomiting.
> 10kg ------ 240 ml ORS/ motion or vomiting.
Nutrition :
continue breast feeding or resume age appropriate normal diet after initial
hydration including adequate caloric intake for maintenance
2-Mild- moderate dehydration
Replacement therapy :------ ORS
50-100ml over 3-4hrs.
Replacement of losses :
<10 kg ------- 60 -120 ml ORS /motion or vomiting
> 10kg ------ 240 ml ORS/ motion or vomiting
Nutrition :
continue breast feeding or resume age appropriate normal diet after initial
hydration including adequate caloric intake for maintenance
6
3-Severe dehydration
Replacement therapy :
lactated Ringer solution or N/S in 20ml/kg IV
until perfusion and mental status improve
Replacement of losses :
100ml ORS over 4hrs , If unable to drink administer through NG tube
OR
5% dextrose in ½ N/S IV at twice maintenance fluid rate.
Or 5% dextrose in ¼ NS with 20meq/L KCL IV.
Nutrition :
continue breast feeding or resume age appropriate normal diet after initial
hydration including adequate caloric intake for maintenance
Indications of I.V. Therapy in case of severe dehydration include:
 age <6 mo,
 prematurity,
 chronic illness,
 fever >38'C if < 3 mo or
o >39"C if 3-36mo,
 bloody diarrhea,
 persistent emesis,
 poor urine output,
 a depressed level of consciousness
Cereal-based oral rehydration fluids can also be advantageous in
malnourished children and can be prepared at home.
Home remedies including: decarbonated soda beverages ,fruit juices,
and tea ; are NOT suitable for rehydration or maintenance therapy as they
have inappropriately high osmolality and low sodium concentrations.
Limitations to oral rehydration therapy include :
 shock,
 an ileus,
 intussusceptions,
7
 carbohydrate intolerance (rare),
 severe emesis,
 and high stool output (>10 ml/kg/hr).
2-Enteral feeding and diet selection
Continued enteral feeding in diarrhea aids in recovery
Once rehydration is complete, food should be reintroduced while oral
rehydration can be continued.
Foods with complex carbohydrates rice, wheat, potatoes, bread, and
cereals, lean meats, yogurt, fruits, and vegetables are also tolerated
Fatty foods or foods high in simple sugars (juices, carbonated sodas) should
be avoided.
MILK
most children with diarrhea are able to tolerate milk and lactose-containing
diets.
Although children with persistent diarrhea are not lactose intolerant,
Alternative strategies for reducing the lactose load while feeding
malnourished children with prolonged diarrhea include addition of milk
to cereals as well as replacement of milk with fermented milk products
such as yogurt.
In case of Milk intolerance:
it may be necessary to administer specialized milk-free diets such as:
chicken-based diet or rice-lentil formulations, green banana or pectin to the
diet shown to be effective in the treatment of persistent diarrhea.
3-ZINC SUPPLEMENTATION
There is strong evidence that Zn supplementation in children with diarrhea
in developing countries leads to
8
reduced duration and
severity of diarrhea and
Reduce mortality
Oral Zn 10-14 days during and after diarrhea
(10 mg/day for infants <6 mo of age and 20 mg/day for >6 mo).
4- ADDITIONAL THERAPIES
The use of probiotic (Lactobacillus,Bifidobacterium)
that have a good safety record
Antimotility agents (loperamide) are contraindicated in children with
dysentery and probably have no role
Antiemetic agents such as the phenothiazines are of little value and are
associated with potentially serious side effects
Ondansetron is an effective and less toxic antiemetic agent.
5-ANTIBIOITIC THEBAPY
antibiotic therapy in selected cases of diarrhea may reduce the duration and
severity of diarrhea and prevent complications .
Nitazoxanide an anti-infective agent, has been effective in the treatment
of a wide variety of pathogens including
 Cryptosporidum parvum, Giardia lamblia,
 Entamoeba histolytica,
 Blastocystis hominis,
 C. difficile, and rotavirus.
PREVENTION:
 Promotion of exclusive breast-feeding
 Improved complementary feeding practice
 Vaccination against: Rota V. ,Shigella and ETEC
 improvement in standards of hygiene, sanitation, and water supply.
9




Further readings
Pathogenesis of Rota virus GE, Cholera
Role of antibiotics in treatment of acute diarrhea (indications)
Types of dehydration according to the biochemical changes.
10