WAFA SAMA’N Pediatrics MD. 1. Incidence:- The second most common cause of death in children Publish Elissa Tickle, Modified 3 years ago

WAFA SAMA’NPediatrics MD.

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Incidence:-The second most common cause of death in

children <5 years.Account for 1.5 million death of children/year

globally.(13% of all deaths).Every child <5 years has 3.6 episode of

diarrhea/year. Mortality due to diarrhea has declined cause

of Rotavirus vaccine, improved nutritional status, better management of disease.

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Etiology:-Feco-oral route transmission.Ingestion of contaminated food or water.Person to person transmission occur in

pathogens infectious in small inoculum ,like Shigella,campylobacter,EHEC,Norovirus,

Rotavirus, E.histolyticum and Giardia.Most common cause is viral like

Rota,norovirus(Norwalk) then adenovirus and enteric viruses.

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Bacterial causes like salmonella,Shigella and E.Coli.

Waterborne outbreaks of diarrhea caused by cryptosporidium commonly and others like:-Shigella, E.coli, Norovirus and Giardia.

Antibiotics associated pseudomembranous colitis is due to Clostridium defficile.

Usually all children acquired Rotavirus, enterovirus and Giardia lamblia in the first 5 years of life. 4

Diarrhea ClassificationPathophysiology

OsmoticSecretoryExudationAbnormal motility

DurationAcute (< 2 weeks)Chronic (> 2 weeks)

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Mechanism of Diarrhea:-Mechanism Non-inflammatory

Enterotoxin/Adherence

InflammatoryInvasion/cytotoxin

Penetration

Location Proximal Small Bowel Colon Distal Small Bowel

Illness Watery Diarrhea Dysentery Enteric Fever

Stool Examination

No fecal leukocytesMild or no lactoferrin

Fecal Neutrophil lactoferrin

Fecal mononuclear leukocyte

ExampleV.cholera,E.coli (ETEC,EPEC,EAEC) ,Norwalk,Giardia,Staphaureus,Cl.perfringes.

Shigella,E.coli(EIEC,EHEC) Salmonella enteritidis,Cl.defficile,E.histolytica.

Salmonella typhiYersina Enterocolitica

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Osmotic diarrheaDef: Increased amounts of poorly absorped,

osmotically active solutes in gut lumenInterferes with reabsorption of waterSolutes are ingested

magnesiumsorbitolmalabsorption of food (mucosal injury, lactase

deficiency)

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Secretory diarrheaExcess secretion of electrolytes, fluid across

mucosaUsually coupled with decrease in absorptionWatery, high-volume diarrhea with

dehydrationEnterotoxins: Cholera, E. coli, food poisoning,

Rotavirus (?), Norwalk virus (?)

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Osmotic/SecretoryVOLUME OF STOOL <200ml/24 hrs >200ml/24 hrs

Response to fasting Diharrea stops Diharrea continues

Stool Na <70 mEq/l >70 mEqu/l

Reducing substances Positive Negative

Stool pH <5 >69

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In secretory Diharrea enterotoxin produced by microorganism cause inhibition of Na-Cl pump but not(glucose-Na) pump.

In inflammatory diharrea extensive histological damage,release of cytokines leads to increase crypt secretion of Chloride ion by increasing c-AMP.Uncoupling of both Na-H,Hco3-CL –and Na-Glucose uptake.

In Shigellosis superficial invasion of colonic mucosa and phagocytic activation with apoptosis and inflammatory interleukins release leading to neutrophilic degranulation.

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Risk Factors:-Environmental contamination of water and food.Young age.Immunedefficiency.Measles.Malnutrition.Lack of exclusive breast feeding.Vitamin A defficiency.Zink defficiency is known also to increase

mortality in pneumonea,measles and diharrea.

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Complications:-Dehydration.Prolongation of diharrea with resultant

malnutritionSecondary infections.Micronutrient defficiency(Zinc,Iron).Extraintestinal manifestations like reactive

arthritis,GuillianBarre(C.jejeuni),glomerulonephritis,HUS and erythema nodosum(salmonella,campylobacter).

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Treatment:-ORS is considered the cornerstone in

treatment because it has appropriate osmolality about 310 mos/Kg.

ORS can’t be given in shock,ileus,vomiting,high stool output>10cclKG

Home made remedies like carbonated beverages(soda),fruit juice are not suitable for rehydration or maintainance because of high osmolality and low Na concentration.

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•Enteral feeding should be continued during recovery from episode of diarrhea.•Although brush border of intestine is affected ,still satisfactory absorption of CHO,protiens and fats can occur.

•Once rehydration is complete food should be reintroduced to replace ongoing losses by emesis or diharrea.

Breast feeding or non diluted formula should be given.

Fatty food or food high in simple sugars should be avoided.

Energy given should be 100 Cal/Kg/d and proteins 2-3glKg/d.

Acute lactose intolerance is seen in some patients ,so they should be given Lactose free formula like replacing some of milk requirements with yogurt or milk free diet like comminuted chicken or elemental milk.

Food like rice soup,vegetables,fruits and yogurt can be given in the recovery period.

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Oral rehydration solutions

Components WHO Ricelyte Pedialyte

Na (mEq/L) 90 50 45

K (mEq/L) 20 25 20

Cl (mEq/L) 80 45 35

Citrate (mEq/L) 30 34 30

Glucose (g/L) 20 30 25

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Additional therapy:-Zinc supplement reduce duration ,severity

and prevent recurring diharrea.Probiotics like non-pathological bacteria,can

restore beneficial intestinal flora,decrease proinflammatory cytokines and increase anti-inflammatory factors

Lactobacillus bifidobacterium and lactobacillus rhamenosus reduced duration in Rota.

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Additional therapy:-Anti-motility(Loperamide) NO Role.Anti-emetics like phenothiazine, no role.Ondansetron is a selective anti 5HT receptors

and a safe anti-emetic can be given as a single dose before ORS if there is vomiting.

Antibiotics should not be given routinely because indiscriminate use lead to bacterial resistance and may prolong bacterial shedding

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Prevention:-Promotion of exclusive breast feeding so no

other fluid or food should be given in 1st 6 months.

Improved complementary feeding preparation with hygenic practice.

Vit-A supplement.Rota virus immunization.oral live attenuated

pentavalent vaccine.

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Viral causes of gastroenteritis

RotavirusCalcivirus(Norwalk)Enteric AdenovirusAstrovirusOthers Torovirus,Coronavirus and Pesivirus

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Rotavirus

Mostly in infants between3-24 months.

Low infection inoculum size so person-person spread is common.

All children exposed by age 4-5 years

Double stranded RNA virusSeveral groups (A-E )Most common cause of viral

diarrhea24

Rotavirus

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PathogenesisSelectively infects &destroys villous tip cells in

small intestine ,gastric mucosa is not affected.Villi have absorptive &digestive functions so

both are affected in Rota viral infection.Viral enteritis enhance mucosal permeability to

macro molecules leading to increase incidence of food allergy.

Infants are more prone to infection because of decrease intestinal reserve , gastric acidity and lack of specific immunity.

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TransmissionFecal-oral Contaminated water suppliesPoor hygieneFood Fomites

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Clinical manifestations:-Incubation period <48 hrs.Low grade fever,vomiting followed by

diharrea lasting<one week,usually watery,no blood or white cells.

Infants commonly develop dehydration.Malnourished children develop severe

&prolonged illness.Newborns usually are asymptomatic some

may develop NEC outbreaks in nurseries.

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Diagnosis of rotavirusElectron microscopy

Small intestineStool

Antigen in stoolcommercial ELISA PCR, nucleic acid probesNo RBC or WBC in stool

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Rotavirus Clinical SyndromesAsymptomatic

carriersDiarrheal illness

2-3 day incubation period

diarrhea, vomiting fever 3-7 days

high infectivity

Complicationsdehydrationchronic diarrheadisseminationNEC

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Prevention of RotavirusNatural immunity 93% protective

(sIgA)Good hand washing&isolation .Vaccine

Was licensed in 1998 for infants 2,4,6 mo. offered 80% protection.

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Norwalk virus“winter vomiting disease” 1968, Norwalk Cause 40% of nonbacterial epidemicsExplosive epidemics

camps, cruise ships, nursing homesFood borne illness

raw shellfish

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Norwalk virus: Clinical Features24-48 hour incubation periodvomiting prominentdiarrhea 1-3 daysless severe than rotavirusSmall 27-35-nm single stranded RNA

virusMost common cause of GE outbreaks in

older children &adultsSimilar to staph food poisoning

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How does Norwalk virus cause diarrhea?

Infection affects proximal small bowelPatchy mucosal injuryMalabsorption? Excess secretion

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Other viruses causing gastroenteritisAdenovirusEnteric serotypes 40,4180-nm single stranded DNA Do not cause respiratory symptomsCommon cause of GE in children and adultsProlonged course 10-14 days

AstrovirusSecond common cause of viral GESingle stranded RNA 30-nm diameterSimilar to Rota infection but milder 36

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Bacterial Etiology:-SalmonellaTwo main species with many different

serotypes(S.Enterica S.bongori)Serotypes are divided according to somatic O antigen and flagella H antigen.

G-ve flagellated rods killed by heat.Transmitted by raw poultry,eggs,vegetables

contaminated water.Person-person spread uncommon because of

large inoculum size.38

PresentationSalmonellosis(acute enteritis):Incubation period 6-72 hrs.Nausea,vomiting,abdominal pain ,fever

diharrhea,usually watery but st bloody.Rarely septicimia and septic shock.Extraintestinal manifestations like

osteomyelitis,septic arthritis,meningitis Usually self limiting disease like food

poisoning.

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Treatment:-Correct dehydrationAntimotility drugs are contraindicated

because they increase incidence of perforation

Antibiotics are not used in simple enteritis because they increase resistance prolonged bacterial shedding &carrier state.

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Treatment:-Antibiotics are indicated in infants <3

monthsIn patients with immune deficiency In patients with typhoid feverIn septicimia and localized infectionIn chronic carrier before cholycystectomy

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Shigella:-There are 4 species (S.dysenteriae S.sonnei

S.flexneri S.bodyii)Aerobic non-motile G-ve rods Transmitted by contaminated water and foodPerson-person is common ,because the

inoculum size is only 100 bacteriaInvasion of colonic mucosa with production of

enterotoxin

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Complications:- Acute bloody diarrhea( tenesmus,crampy

pain with fever)Hemolytic uremic syndrome(acute renal

failure,hemolytic anemie,thrombocytopenia)Neurological complications (lethargy,coma

and convulsions)Reiter syndrome(conjunctivitis urethritis and

arthritis)

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Treatment:-Fluid and electrolyte correctionAntibiotics treatment in all children with

shigellosis.Antibiotics are given to shorten duration of

illness so the child will not be infectiousProlonged course if untreated with resultant

malnutritionCeftriaxone is drug of choice

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Pseudomembranous Colitis :-Clostridium difficile is the causative bacteriaIt is found in colon as inactive spore formAntibiotics disrupt normal flora in intestine

so dormant spores are activated They produce toxin that damage the colonic

mucosa with production of membraneAntibiotics implicated mostly

Clindamycin,Ampicillin,amxycillinOral metronidazole or Vancomycin is drug of

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AmebiasisTwo species that are genetically identical

E.histolyticum and E.disparE.dispar usually asymptomatic carrierE.histolytica in 90% of cases are

asymptomatic cyst passerInfection transmission is by cyst because they

are resistant to cold and chlorinationTrophozoites are not infectiousPerson-person transmission can occur

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SymptomsAmebic dysentery with colicky abdominal

pain frequent bowel motions,bloody diarrhea and tenesmus

No general signs and symptomsLow grade feverMay invade intestinal mucosa to cause

abscess in liver and rarely in brainChronic amebic colitis indistinguishable from

IBD

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TreatmentAll individuals with cyst or trophozoites in

their stool whether symptomatic or not should be treated

Metronidazole is the drug of choice for invasive amebiasis

Iodoquinol and paromomycin is the treatment of choice for amebic cyst

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Giardia lambliaFlagellated protozoan infects the duodenum

and proximal jejunumIt is found as cyst and trophozoites form10-100 cysts are enough to cause infectionWater and food borne infection Person-person infection is commonMost common intestinal parasiteCysts are resistant to chlorination but killed

by boiling

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SymptomsAcute infectious diarrhea no mucus or blood

in stoolChronic diarrhea leading to malabsorption

and failure to thrive with fats and sugar in stool

Most infections are asymptomaticNo extra intestinal spreadDiagnosed by stool analysis or duodenal

aspirate and biopsy

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TreatmentAsymptomatic carriers are not treated Albendazole treatment for 5 days Others like metronidazole,furazolidone and

paromomycin are effective treatmentInfections in pts who have

agammaglobulinemia should be treated

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Antimicrobial Therapy:- Organism Antimicrobial Agent Indications for Rx

Campylobacter Erythromycin/Quinolones

Early in the course of disease

Clostridium difficile Metronidazole/Vancomycin

Moderate to severe disease

E.coli TMP/SMZSevere or prolonged illness

Nursery epidemics

SalmonellaCefotaxime/CeftriaxoneAmpicillin/TMP/SMX

Bacteremia,suppurationInfants<3mon,typhoid fever

ShigellaAmpicillin,CeftriaxoneCiprofloxacin

All cases +ve stool

Giardia lamblia Metronidazol/albendazol

Entamoeba hisolyticum Metronidazol/iodoquinol Trophozytes/cyst

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The End.Thank You For Listening.

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