Acute Gastroenteritis.ppt

Getting to know what is it

1. Acute Gastroenteritis

2. Diarrhoea
Definition
•>3looseorwaterystools/day.
•Dehydrationandelectrolytelossescausethe
primarymorbidityofacutegastroenteritis.
•Diarrhoeaamong theinitialsignsof
nongastrointestinaltractillnesses,including
meningitis,bacterialsepsis,pneumonia,otitis
media,andurinarytractinfection.

3. Causes
•Viruses, bacteria, and parasites
Others include:
•food poisoning (preformed toxins)
•medications,
•recent ingestion of poorly absorbable
sugars (eg, lactulose).

4. Bacterial infections
E coli:
•Enteropathogenic E.coli [EPEC]
•Enterotoxigenic E.coli [ETEC]
•Enteroaggregative Ecoli [EAEC]
Enteroinvasive Ecoli [EIEC]
•Enterohemorrhagic E coli [EHEC]

5. Bacterial infections
•Campylobacter species
•Aeromonas,
•Shigella,
•Yersinia species and
•Salmonella species
•Vibrios species, especially Vibrios cholerae
•Clostridium difficile

6. Bacterial infections
•Inpatientswithsicklecelldisease,
Salmonellaspeciesarethemostfrequent
causeofgastroenteritis.

7. Food poisoning
•Bacilluscereus,
•Clostridiumperfringens,C.Botulinum,
•Staphylococcusaureus,
•Salmonellaspecies,
•ToxigenicE.coli(ETECandEHEC)
•Vibriospp.(includingV.choleraeandV.
parahaemolyticus),andcertainspeciesof
•Campylobacter,Yersinia,Listeria,and
Aeromonas

8. Parasites:
•Giardia lamblia
•Cryptosporidium parvum
•Cyclospora cayetanensis.
•Entamoeba coli,
•Endolimax nana,
•Iodamoeba butschlii,and
•Blastocystis hominis.

9. Viral infections
•Rotavirus
•Norwalk virus
•Enteric adenoviruses
•Small, round structured viruses,
•Astroviruses and
•caliciviruses

10. In patients with HIV/AIDS
•Mycobacterium avium
•Cytomegalovirus and rotavirus
•Cryptosporidiumspecies,
•Isosporabelli,
•Giardia lamblia,
•Entamoebahistolytica,
•Cyclosporaspecies, and
•Microsporidia.
Note the above microorganisms are also the
causes of chronic diarrhea in patients with
HIV/AIDS

11. Pathophysiology

12. Viral
•Lysisofenterocytes
•interferencewiththebrushborderfunction
thatleadstomalabsorptionofelectrolytes
•stimulation of cyclic
adenosinemonophosphate (cAMP),
•carbohydrate malabsorption.

13. Bacterial
•Elaboration of toxin by enterotoxigenic
pathogens and the invasion and
inflammation of mucosa by invasive
pathogens.
Parasitic organisms
•invade epithelial cells and cause villus
atrophy and eventual malabsorption.

14. •Diarrheaisduetoexcessosmotically
activesubstancesinthestool,theresultof
eitherdecreasedabsorptionofnutrients
andelectrolytesorexcesssecretionof
electrolytes,orboth.

15. Osmotic Diarrhea
•Duetothepresenceofanunabsorbable
orpoorlyabsorbablesolutethatexertsan
osmoticpressureeffectacrossthe
intestinalmucosa,resultinginexcessive
wateroutput.

16. Osmotic Diarrhea
•Disaccharidasedeficiency(lactose
intolerance),
•Malabsorption,poorlyabsorbedsugars
(lactulose,sorbitol,mannitol),
•Laxatives(magnesium,sodiumcitrate,
sodiumphosphate),and
•Magnesium-containingantacids.
•Rotavirus

17. Secretory Diarrhea
•Toxinsbindtoenterocytereceptors,
causingchloride-mediatedsecretion
stimulatedbysecondmessengers(e.g.,
cAMP,cGMP,andcalcium)resultingin
increased secretion, decreased
absorption,orboth.

18. Secretory Diarrhea
•V.cholerae01and139,
•certainstrainsofEscherichiacoli,
shigella,salmonella,andother
pathogenicbacteria
•Rotavirus
•Stimulantlaxatives(phenolphthalein,
senna,bisacodyl)

19. Signs and symptoms

20. Dehydration
•Manifestedasincreasedthirst,decreased
urinaryoutputwithdarkurine,inabilityto
sweat,andorthostaticchanges.
•Inseverecases,itmayleadtoacuterenal
failureandmentalstatuschangeslike
confusionanddrowsiness.

21. Type of diarrhoea
•Small-intestinaldiseaseistypicallyhigh-
volume,watery,andoftenassociatedwith
malabsorption,anddehydrationis
frequent.
•Colonicinvolvementismoreoften
associatedwithfrequentsmall-volume
stools,withthepresenceofbloodanda
sensationofurgency.

22. Toxigenic infection
Patientsingestingtoxinsorthosewith
toxigenicinfectiontypicallyhavenausea
andvomitingasprominentsymptoms
alongwithwaterydiarrheabutrarelyhave
ahighfever.

23. Invasive bacteria
Campylobacter,Salmonella,andShigella
organisms,andorganismsthatproduce
cytotoxinssuchasClostridiumdifficileand
enterohemorrhagicEcoli(serotypeO157:
H7),causesevereintestinalinflammation,
abdominalpain,andoftenfever;
occasionallyperitonealsignsmaysuggest
asurgicalabdomen.

24. Enteric fever
•causedbySalmonellatyphiorSalmonella
paratyphi,isaseveresystemicillnes
manifestedinitiallybyprolongedhigh
fevers,prostration,confusion,and
respiratorysymptoms,followedby
abdominaltenderness,diarrhea,andrash.

25. Lab Studies
•Electrolyte
•BUN(bloodureanitrogen)
•serumcreatinine
•RBS
•Acutediarrheasareusuallyinfectiousin
origin.

26. •StoolMCSplusGramstainofthestools
mayhelpdifferentiateinfectiousfrom
noninfectiousdiarrhea.
•Stool Ova

27. Treatment

28. Rehydration
Intherehydrationphase,thefluiddeficitis
replacedquicklyandclinicalhydrationis
attained.
Ifpatientisinhypovolemicshock,give
bolusofvolumeexpanders;normalsaline
1lin30minandrepeatbolusifnormalbp
notattained,3bolusescanberepeated,
followedbymaintainancefluidin24hrsof
100ml/kgforthe1
st
10kg
50mlfornext10kg
20mlfortheremainingKgs

29. Rehydration
•Managedehydrationaggressivelyin
patientswhohavesicklecelldiseaseto
preventsequelae(eg,infarction,stroke,
splenicsequestration).
•Administrationof1.5timesthenormalrate
ofmaintenancefluidinfusionisaroutine
practice.

30. Antimicrobial Therapy
•Empirictreatmentofallpatientsisnot
warrantedbecausethemajorityofpatients
havemild,self-limiteddiseaseduetoviruses
ornoninvasivebacteria
•Zincsulphate
•Antibioticadministrationconsideredfor:
–veryyoungpatientswithSalmonella
–immunocompromised,
–systemicallyill.

31. Specific pathogens to be
treated include:
•Shigella,
•Vibriocholerae,
•Clostridiumdifficile,
•Parasites,
•extraintestinalsalmonellosis
(Recentevidencesuggeststhatantibiotictreatmentof
enterohemorrhagicEcoliinfectionmayincreasetheriskfor
developinghemolyticuremicsyndrome).