Acute infectious diarrhea

Food poisoning &

Acute gastroenteritis

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

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

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

ORS constituents- per liter water

NaCl- 3.5 gmNaHCO3- 2.5 gm

KCl- 1.5 gmGlucose-20 gm

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

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

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

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

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

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