Gastroenteritis Flashcards
What is gastroenteritis?
- Diarrhoea (+ vomiting)
- Due to enteric infection: viruses, bacteria or parasites
Define acute diarrhoea?
>=3 episodes of watery stool/day for <14 days
Define dysentery?
Infectious gastroenteritis with bloody diarrhoea
Define persistent diarrhoea?
Acutely starting diarrhoea lasting > 14 days
Define travellers diarrhoea?
Starting during, or shortly after, foreign travel
Define food poisoning?
Disease cuased by consumption of food/water
Common viral causes of gastroenteritis?
- Norovirus
- Rotavirus
- Astrovirus
- Adenovirus
- Sapovirus
- CMV
Common bacterial causes of gastroenteritis?
- Shigella
- Salmonella
- E. coli
- S. aureus
- C. difficle
- C. perfringens
- Campylobacter
- Listeria
- Vibrio cholerae
- Bacillus cereus
Parasites which commonly cause gastroenteritis?
- Giardia
- Cryptosporidium
- Entamoeba histolytica
- Trichinella
- Trichuriasis
Describe Norovirus?
- 1d incubation
- Epidemic gastroenteritis
Describe Rotavirus?
- 1-3d incubation
- Most children affected by 5
- Live vaccine available
Describe astrovirus?
- 5d incubation
- Less severe than norovirus
Describe Adenovirus?
- 3-10d incubation
- Enteric adenovirus
- Mainly children
describe CMV?
- Asymptomatic
- If immunosupressed:
- Colitis, hepatitis, pneumonia
Which pathogens cause diarrhoea with and without blood?
What is a majory cause of traveller’s diarrhoea?
Enterotoxigenic E. coli
How can traveller’s diarrhoea be prevented?
- Boil water
- Cook thoroughly
- Peel fruit and vegetables
Presentation of traveller’s diarrhoea?
- During first week of travel
- Enterotoxigenic e. coli
- Watery diarrhoea, cramps, nausea
- Giardia lamblia
- Bloating, belching
- Campylobacter and shigella
- Colitic symptoms, cramps
Treatment for traveller’s diarrhoea?
- Oral rehydration
- Antimotility agents
- Loperamide, bismuth salicylates
- Antibiotics (usually not indicated)
Describe a home-made oral rehydration recipe?
- 6 teaspoons of sugar
- Half teaspoon of salt
- 1L of clean drinking water
Contraindications for antimotility agents?
- Severe pain
- Bloody diarrhoea
- ** May indicate invasive colitis
Describe Norovirus?
- Single-stranded RNA virus
- Transmitted by contact with someone infected, environment or food
- Presents 12-48hrs after exposure, lasts 24-72hrs
- Vomiting, watery diarrhoea, cramps, nausea.
Describe the diagnosis and treatment of norovirus?
- Diagnosis
- Clinical, stool sample reverse transcriptase PCR
- Treatment
- Supportive
- Anti-motility agents
- Usually self-limiting
Describe Rotavirus?
- Double stranded RNA, wheel-like appearance
- Most common cause of gastroenteritis in children
- Watery diarrhoea and vomiting, fever, abdo pain
Describe the diagnosis and treatment of Rotavirus?
- Diagnosis
- Clinical
- Antigen in stool
- Treatment
- Supportive
- Live vaccine (antigen seen in stool after)
Describe Enterotoxigenic E. coli?
- Gram negative anaerobe
- Heat-stable/heat-labile toxin stimulates water efflux into gut lumen
- Watery diarrhoea, cramps
- Important cause of travellers diarrhoea
Describe the diagnosis and treatment of Enterotoxigenic e. coli?
- Diagnosis
- Clinical
- Indentification of toxin in stool culture
- Treatment
- Supportive
- Same treatment as traveller’s diarrhoea
Describe Clostridium perfringens (type A)?
- Gram positive anaerobe
- Produces enterotoxin, spores survive cooking and germinate during unrefridgerated storage
- Sudden-onset diarrhoea, cramps, last <24 hrs
Describe Cholera?
- Gram netative aerobic, coma shaped
- Flagellated so mobile
- Faecally contaminated water
- Types 01 and 0139 cause disease
Describe the diagnosis of Cholera?
- Clinical
- Watery, rice-water stool, vomiting, dehydration, metabolic acidosis
- Identification of 01 or 0139 in stool
- Rapid dipstick testing
- Culture
Describe the treatment of Cholera?
- Oral rehydration salts
- Requires clean water
- IV fluids if dehydrated
- Ringer’s lactate / 0.9% NaCl
- Doxycycline if severe dehydration
- Zinc shortens illness in children
Describe the prevention of cholera?
- Clean water
- Oral cholera vaccine
Name the types of shigella?
- Boydii
- Sonnei
- Flexneri
- Dysenteriae
Describe shigella gastroenteritis?
- Gram negative anaerobe
- Watery/bloody diarrhoea, pain, tenesmus, fever
- Complications: bacteraemia, reactive arthritis, HUS
Describe the diagnosis and treatment of shigella gastroenteritis?
- Diagnosis
- Stool culture
- PCR/enzyme immunoassay
- Treatment
- Supportive
- Nutrition: green bananas, zinc, vitamin A
- Anitbiotics if systemically unwell
- Avoid antidiarrhoeals => toxic dilatation
Describe gastroenteritis from enterohaemorrhagic / shiga-toxin producing E. coli (STEC)?
- Gram negative anaerobe
- Produces veratoxins
- Diarrhoea, haemorrhagic colitis, HUS
Describe the treatment of STEC?
- Diagnosis
- Stool culture
- PCR/enzyme immunoassay for shiga-toxin
- Treatment
- Supportive
- NO ANTIBIOTICS => increased risk of HUS
Describe gastroenteritis caused by campylobacter?
- Gram negative, spiral shaped rod
- Bloddy diarrhoea, pain, fever, headache
- Complications: bacteraemia, hepatitis, pancreatitis, miscarriage, Guillain-barre
Describe the diagnosis and treatment of campylobacter gastroenteritis?
- Diagnosis
- Stool culture
- PCR/enzyme immunoassay
- Treatment
- Supportive
- Antibiotics only for invasive cases
Describe Salmonella enterocolitis?
- Gram negative anaerobe, motile bacilli
- Diarrhoea, cramps, fever
- Invasive infection => sepsis, meningitis, osteomyelitis
Describe the diagnosis and treatment for salmonella enterocolitis?
- Diagnosis
- Stool culture
- PCR
- Treatment
- Supportive
- Antibiotics only for severe disease
Describe Yersinia enterocolitica?
- Gram negative rod
- Diarrhoea, fever, pain (appendicitis mimic)
- Erythema nodosum, reactive arthritis
Describe the diagnosis and treatment of Yersinia enterocolitica?
- Diagnosis
- Stool culture
- Agglutination titres
- Treatment
- Antibiotics in severe disease
