Getting to know what is it

1. Acute Gastroenteritis

2. Diarrhoea
Definition
• >3 loose or watery stools/day.
• Dehydration and electrolyte losses cause the
primary morbidity of acute gastroenteritis.
• Diarrhoea among the initial signs of
nongastrointestinal tract illnesses, including
meningitis, bacterial sepsis, pneumonia, otitis
media, and urinary tract infection.

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
• In patients with sickle cell disease,
Salmonella species are the most frequent
cause of gastroenteritis.

7. Food poisoning
• Bacillus cereus,
• Clostridium perfringens, C. Botulinum,
• Staphylococcus aureus,
• Salmonella species,
• Toxigenic E. coli (ETEC and EHEC)
• Vibrio spp. (including V. cholerae and V.
parahaemolyticus), and certain species of
• 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
• Cryptosporidium species,
• Isospora belli,
• Giardia lamblia,
• Entamoeba histolytica,
• Cyclospora species, and
• Microsporidia.
Note the above microorganisms are also the
causes of chronic diarrhea in patients with

11. Pathophysiology

12. Viral
• Lysis of enterocytes
• interference with the brush border function
that leads to malabsorption of electrolytes
• 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. • Diarrhea is due to excess osmotically
active substances in the stool, the result of
either decreased absorption of nutrients
and electrolytes or excess secretion of
electrolytes, or both.

15. Osmotic Diarrhea
• Due to the presence of an unabsorbable
or poorly absorbable solute that exerts an
osmotic pressure effect across the
intestinal mucosa, resulting in excessive
water output.

16. Osmotic Diarrhea
• Disaccharidase deficiency (lactose
intolerance),
• Malabsorption, poorly absorbed sugars
(lactulose, sorbitol, mannitol),
• Laxatives (magnesium, sodium citrate,
sodium phosphate), and
• Magnesium-containing antacids.
• Rotavirus

17. Secretory Diarrhea
• Toxins bind to enterocyte receptors,
causing chloride-mediated secretion
stimulated by second messengers (e.g.,
cAMP, cGMP, and calcium) resulting in
increased secretion, decreased
absorption, or both.

18. Secretory Diarrhea
• V. cholerae 01 and 139,
• certain strains of Escherichia coli,
shigella, salmonella, and other
pathogenic bacteria
• Rotavirus
• Stimulant laxatives (phenolphthalein,
senna, bisacodyl)

19. Signs and symptoms

20. Dehydration
• Manifested as increased thirst, decreased
urinary output with dark urine, inability to
sweat, and orthostatic changes.
• In severe cases, it may lead to acute renal
failure and mental status changes like
confusion and drowsiness.

21. Type of diarrhoea
• Small-intestinal disease is typically high-
volume, watery, and often associated with
malabsorption, and dehydration is
frequent.
• Colonic involvement is more often
associated with frequent small-volume
stools, with the presence of blood and a
sensation of urgency.

22. Toxigenic infection
Patients ingesting toxins or those with
toxigenic infection typically have nausea
and vomiting as prominent symptoms
along with watery diarrhea but rarely have
a high fever.

23. Invasive bacteria
Campylobacter, Salmonella, and Shigella
organisms, and organisms that produce
cytotoxins such as Clostridium difficile and
enterohemorrhagic E coli (serotype O157:
H7), cause severe intestinal inflammation,
abdominal pain, and often fever;
occasionally peritoneal signs may suggest
a surgical abdomen.

24. Enteric fever
• caused by Salmonella typhi or Salmonella
paratyphi, is a severe systemic illnes
manifested initially by prolonged high
fevers, prostration, confusion, and
respiratory symptoms, followed by
abdominal tenderness, diarrhea, and rash.

25. Lab Studies
• Electrolyte
• BUN (blood urea nitrogen)
• serum creatinine
• RBS
• Acute diarrheas are usually infectious in
origin.

26. • Stool MCS plus Gram stain of the stools
may help differentiate infectious from
noninfectious diarrhea.
• Stool Ova

27. Treatment

28. Rehydration
 In the rehydration phase, the fluid deficit is
replaced quickly and clinical hydration is
attained.
 If patient is in hypovolemic shock,give
bolus of volume expanders; normal saline
1l in 30 min and repeat bolus if normal bp
not attained, 3 boluses can be repeated,
followed by maintainance fluid in 24 hrs of
100ml/kg for the 1st 10kg
50ml for next 10kg
20ml for the remaining Kgs

29. Rehydration
• Manage dehydration aggressively in
patients who have sickle cell disease to
prevent sequelae (eg, infarction, stroke,
splenic sequestration).
• Administration of 1.5 times the normal rate
of maintenance fluid infusion is a routine
practice.

30. Antimicrobial Therapy
• Empiric treatment of all patients is not
warranted because the majority of patients
have mild, self-limited disease due to viruses
or noninvasive bacteria
• Zinc sulphate
• Antibiotic administration considered for:
– very young patients with Salmonella
– immunocompromised,
– systemically ill.

31. Specific pathogens to be
treated include:
• Shigella,
• Vibrio cholerae,
• Clostridium difficile,
• Parasites,
• extraintestinal salmonellosis
(Recent evidence suggests that antibiotic treatment of
enterohemorrhagic E coli infection may increase the risk for
developing hemolytic uremic syndrome).