W25 - Gastroenteritis Flashcards
What is gastroenteritis?
A rapid onset diarrheal illness, lasting less than 2 weeks with diarrhoea (loose and unformed stool) three or more times a day or at least 200 g of stool which is either viral or bacterial in aetiology
What is acute, persistent, and chronic diarrhoea?
Acute = less than 14 days (viral or bacterial usually)
Persistent = between 14-29 days
Chronic = >30 days (non-infectious or parasites usually)
Smll bowel diarrhoea is usually ….
Large bowel diarrhoea is usually ….
Smll bowel diarrhoea = watery, associated with crampy abdominal pain, bloating, gas. Usually no blood or fever.
Large bowel diarrhoea = small volume, painful stool which occurs often with blood, mucus, fever, and accompanying inflammatory cells found in stool.
3 RF categories for gastroenteritis
- Foodborne
- Exposure related (travel, occupation, animal contact, childcare facility, outbreak)
- Host related (immunosuppressed, MSM, young, elderly, anal-genital, oral-anal, or digital-anal contact, haemochromatosis)
What is the definition of gastroenteritis?
A) more than 2 weeks of symptoms
B) more than 1 week of symptoms
C) more than 3 weeks of symptoms
B) more than 1 week of symptoms
Gastroenteritis - extra-intestinal manifestations:
Aortitis, osteomyelitis, deep tissue infection
Which pathogens are mostly responsible for these?
salmonella
yersinia
Gastroenteritis - extra-intestinal manifestations:
haemolytic anaemia
Which pathogens are mostly responsible for these?
campylobacter
yersinia
Gastroenteritis - extra-intestinal manifestations:
glomerulonephritis
Which pathogens are mostly responsible for these?
shigella
campylobacter
yersinia
Gastroenteritis - extra-intestinal manifestations:
haemolytic uraemic syndrome (HUS)
Which pathogens are mostly responsible for these?
STEC (shiga-toxin producing e coli)
shigella dysenteriae serotype 1
Gastroenteritis - extra-intestinal manifestations:
erythema nodosum
Which pathogens are mostly responsible for these?
Yersinia
campylobacter
salmonella
shigella
Gastroenteritis - extra-intestinal manifestations:
Reactive arthritis
Which pathogens are mostly responsible for these?
Salmonella
shigella
campylobacter
yersinia
rarely giardia
Gastroenteritis - extra-intestinal manifestations:
meningitis
Which pathogens are mostly responsible for these?
listeria
salmonella (infants <3m of age are at high risk)
staphylococci gastroenteritis:
- spread by?
- catalase? cogulase? G stain features
- blood agar features
- clinical picture
staphylococci gastroenteritis:
- spread by skin lesions on food handlers
- catalase +, coagulase + G+ cocci clusters
- yellow colonies on blood agar
- clinical picture = prominent vomiting + watery, non-bloody diarrhoea
(self limiting)
What is the bacteria associated with chinese fried rice?
Bacillus Cereus
Why is bacillus cereus problematic in chinese fried rice?
B/c spores of bacilus cereus germinate in reheated fried rice
Bacillus cereus:
- Gram properties?
- types of toxin?
- Clinical picture of gastroenteritis?
Bacillus cereus:
- Gram properties = G+ rod spores
- types of toxin = 2 types, 1) heat stable emetic toxin and 2) heat labile diarrhoeal toxin
- Clinical picture of gastroenteritis = watery, non-bloody diarrhoea, self-limited
Clostridia are a gram positive/negative aerobe/anaerobe group
Clostridia are a gram positive anaerobe group
2 groups of clostridium and what they each cause?
- Clostridium botulinum = botulism
- Clostridium pefringens = food poisoning
Clostridium botulinum:
- Source:
- Pathophysiology:
- Clinical picture:
Clostridium botulinum:
- Source: canned or vacuum packed food (honey)
- Pathophysiology: ingestion of preformed toxin (inctivated by cooking)
- Clinical picture: botulism via blocked Ach release from PNS
Clostridium pefringens
- Source:
- Pathophysiology:
- Clinical picture:
Clostridium pefringens
- Source: reheated food (meat)
- Pathophysiology: superantigen (enteroxin affects small bowel)
- Clinical picture: food poisoning with watery diarrhoea, cramps, litte vomiting lasting 24h
Clostridium difficile can cause ___ ____
Clostridium difficile can cause Pseudomembranous colitis
Clostridium difficile:
- 2 toxins?
- when does it usually occur?
- Treatment?
Clostridium difficile:
- 2 toxins = toxin A (endotoxin), toxin B (cytotoxin)
- when does it usually occur = after/during abx course
- Treatment = vancomycin (PO), stop abx where possible
Listeria monocytogenes:
- bacterial properties?
- growth temp?
- type of infection?
- treatment?
Listeria monocytogenes:
- bacterial properties = G+, B haemolytic, tumbling motility
- growth temp = 4 degrees celcius (refrigeration causes cold enhancement)
- type of infection = watery diarrhoea, cramps, fever, little vomiting
- treatment = amoxicillin
Travellers diarrhoea is caused by…
E coli (mainly ETEC - enterotoxigenic E coli)
salmonella enterocolitis:
- transmission?
- bacteraemia?
- clinical picture?
- treatment?
salmonella enterocolitis:
- transmission = poultry, eggs, meat
- bacteraemia = infrequent (<5%)
- clinical picture = inflammatory diarrhoea, fever, mucus, or bloody stools
- treatment = usually none, resolves in 7 days
salmonella typhi (typhoid fever):
- transmission?
- bacteraemia?
- clinical picture?
- treatment?
salmonella typhi (typhoid fever):
- transmission = only by humans
- bacteraemia = blood culture + in 40-80%
- clinical picture = slow onset fever and constipation, splenomegaly, rose spots, anaemia, bradycardia, hemorrhage, perforation, BM involvement in some cases. first constipated, then diarrhoea a few weeks later.
- treatment = abx course
Shigella:
- Transmission?
- Toxin?
- Clinical picture?
- Treatment?
Shigella:
- Transmission = contaminated food, animal contact, MSM population high risk
- Toxin = shiga toxin
- Clinical picture = abdo pain + diarrhoea, bloody in 50%, fever, vomiting
- Treatment = self-limiting to about 7 days. abx if persistent.
Vibrio cholerae:
- transmission?
- toxins?
- Clinical picture?
Vibrio cholerae:
- transmission = contamination of water and food from human faeces (shellfish, oyster, shrimp)
- toxins = enterotoxin A and B (causes stimulation of small bowel)
- Clinical picture = massive diarrhoea (rice water stool) without inflammatory cells
Most common cause of gastroenteritis when cruising in the Carribean or when in Japan?
- source?
vibrio parahaemolyticus
- source: ingestion of raw or undecooked seafood (oysters)
Campylobacter:
- transmission?
- clinical picture?
- treatment?
- complications?
Campylobacter:
- transmission = via contaminated food and water with animal faeces
- clinical picture = watery, foul-smelling diarrhoea + blood, fever, severe abdo pain. loos stools >10xday
- treatment = often self-limiting, lasts 7d. only treat if prolonged.
3 complications from campylobacter gastroenteritis?
- GBS syndrome
- reactive arthritis
- Reiter’s
Name 3 protoza that cause gastroenteritis?
- Giardia lamblia
- Entamoeba histolytica
- Cryptosporidium parvum
Entamoeba histolytica
- pathophysiology
- Clinical picture
- Treatment
-
Entamoeba histolytica
- pathophysiology = ingestion of cysts => trophozoites in ileum => colonise cecum, colon => flask shaped ulcers
- Clinical picture = no symptoms to severe symptoms = Amoebiasis = dysentery, flatulence, tenesmus, weight loss, diarrhoea (chronic), liver abscess
- Treatment = metronidazole + paromomycin
-
Giardia lamblia:
- Transmission?
- Clinical picture?
- Treatment?
Giardia lamblia:
- Transmission = ingestion of cyst from faecally contaminated water/food, common in travellers, hikers, day care, MSM
- Clinical picture = foul-smelling non-bloody dairrhoea, cramps, flatulence, no fever
- Treatment = metronidazole
Cryptosporidium parvum:
- Transmission?
- Clinical picture?
- Treatment?
Cryptosporidium parvum:
- Transmission = contact with contaminated water
- Clinical picture = watery diarrhoea, severe in immunocompromised
- Treatment = reconstitution of immune system
Noravirus:
- ID?
- Transmission?
- Clinical picture?
Noravirus:
- ID = very low (hence causes outbreaks)
- Transmission = faeco-oral route
- Clinical picture = watery diarrhoea for 2-3 days
Rotavirus:
- Where does it replicate?
- Who is affected?
- Clinical picture?
Rotavirus:
- where does it replicate = mcosa of small intestine
- Who is affected = children 6m to 2 years usually. sometimes elderly
- Clinical picture = 3-8 d of watery diarrhoea, vomiting less prominent than in norovirus
Which extra-intestinal manifestations are associated with salmonella infection?
A) erythema nodosum
B) abscess formation
C) aortitis
C) aortitis
Which virus is commonly associated with gastroenteritis outbreaks?
A) Adenovirus
B) Noravirus
C) Rotavirus
B) Noravirus
