This document discusses various causes of acute infectious diarrhea including food poisoning caused by Staphylococcus aureus and Bacillus cereus producing preformed exotoxins as well as viral and bacterial pathogens like rotavirus, ETEC, and Vibrio cholerae producing enterotoxins. Evaluation involves assessing duration of symptoms, stool characteristics, and signs of dehydration or inflammation. Management consists of oral rehydration with solutions like ORS, antiemetics, antibiotics for invasive causes, and prevention through hygiene and vaccination. Specific conditions discussed in more detail include cholera, E. coli pathotypes, Salmonella Typhi causing typhoid fever, and constituents of ORS.

1. Acute infectious diarrhea
Food poisoning
&
Acute gastroenteritis

2. Causes
 Food-poisoning- preformed exotoxin
 S.aureus, B,cereus, C.perfringens
 Non-inflammatory- viral/enterotoxin- proximal
small intestine
 Viral- rotavirus, norwalk-like virus
 Bacteria- ETEC, V.cholerae
 Parasite- Giardia
 Inflammatory- cytotoxin/invasive-
distal small intestine or colon
 Parasite- E.histolytica
 Bacteria- Shigella, Salmonella, EHEC/EIEC,
Campylobacter, Yersinia, V.parahemolyticus

3. Evaluation
 History-
 Duration- >2 weeks is chronic
 Fever- suggests invasive disease
 Stool- dysentery-inflammatory, rice water-Cholera
 Abdominal pain- inflammatory>non-inflammatory
 Tenesmus- proctitis- Shigellosis/Amoebiasis
 Vomitting- s/o food poisoning
 Prior antibiotic use- C.difficile-pseudomembranous colitis
 Examination-
 Fever, e/o dehydration- tachycardia, hypotension, weight loss
 Stool examination-
 For WBC- presence s/o inflammatory cause

4. Management
 Dx-
 Clinical & stool examination
 Assess hydration status
 Treatment-
 No specific dietary restrictions or recommendations
 Continue breast-feeding
 ORS- nimbu-paani, rice water, commercial preparations
 IV fluids- Ringer’s lactate- vomiting, ileus, altered sensorium
 Antiemetics- metoclopramide, domperidone
 Antibiotics- dysentery, pseudomembranous colitis, immunosuppressed
 Antimotility agents- Loperamide, not in children
 Prevention-
 Sanitation & hygiene
 Vaccine- rotavirus, typhoid, cholera

5. ORS constituents- per liter water
NaCl- 3.5 gm
NaHCO3- 2.5 gm
KCl- 1.5 gm
Glucose-20 gm

6. Food poisoning
 Due to preformed enterotoxin
 Abrupt onset
 S.aureus-
 1-6 hours, intense vomiting with diarrhea
 C.perfringens-
 6-12 hours, profuse diarrhea with cramps & nausea
 B.cereus-
 Reheated rice- 1-6 hours, severe vomiting with diarrhea
 Meat/gravy- 6-12 hours, severe diarrhea with nausea/vomiting
 Rx- supportive- antiemetics & ORS

7. Escherichia coli
 Gram –ve bacillus
 Normal commensal in human gut
 Virulent types-
 Enterotoxigenic- leading cause of watery diarrhea,
most common cause of travellers’ diarrhea
 Enteropathogenic- diarrhea with mucus
 Enteroinvasive- profuse diarrhea with fever
 Enterohemorrhagic- dysentery, can cause HUS
 Enteroaggregative- watery diarrhea
 Rx- supportive,
fluoroquinolones shorten duration

8. Cholera
 Caused by bacteria V.cholerae
 Primarily affects small-intestine
 People with O blood group more affected,
carriers of cystic fibrosis are protected
 Toxin leads to cAMP activation causing
secretion of water, Na, K, Cl & HCO3
 Causes profuse diarrhea (rice water),
with abdominal pain, ± vomiting

9. Management
 Dx-
 Clinical
 Stool enrichment/culture
 Rx-
 ORS, ± IV fluids
 Antibiotics shorten duration- Doxycycline, cotrimoxazole
 Prevention-
 Whole cell inactivated oral vaccine
 Sanitation
 Proper sewage disposal
 Water treatment/purification

10. Salmonella typhi
 A gram –ve bacillus
 Causes diarrhea with mild fever or TYPHOID-
enteric fever
 Stages- each lasting ~1 week
 1- mild fever, relative bradycardia, malaise, leucopenia,
blood culture +ve, Widal test -ve
 2- high fever, Rose spots on trunk, delirium, bradycardia,
diarrhea (occasionally constipation), HSmegaly,
blood culture/Widal test +ve
 3- high fever, delirium, complications- hemorrhage, perforation,
peritonitis, cholecystitis, metastatic abscess
 4- resolution/defervescence

11. Management
 Dx-
 Clues- relative bradycardia, coated tongue, lymphopenia, splenomegaly
 Blood/marrow/stool culture
 Widal test- Ab against O/H Ag- preferably 4-fold rising titres
(high false +ve rate due to cross-reactivity with
other Salmonella species & malaria)
 Rx-
 Antibiotics- 3rd
/4th
generation cephalosporin- oral/IV x 10 days
 Supportive- rehydration
 Surgery, as required for complication- hemorrhage, perforation
 Prevention-
 Sanitation & hygiene
 Vaccine- live oral/injectable polysaccharide, booster every 5/2 years