Gastroenteritis

Question 1

What is supportive managment?

Answer 1

No antibiotics

Fluids

Question 2

Name 6 GI infections

Answer 2

Bacterial gastroenteritis
Viral gastroenteritis
Intra-abdominal sepsis
Antimicrobial stewardship
Parasites/Travel
STI/HIV related infections
Viral Hepatitis

Question 3

How many deaths per year occur from GI illness?

Answer 3

1.4 Million

Question 4

What are the 6 risk factors for GI infections?

Answer 4

Malnutrition
Closed/Semi-closed communities
Exposure to contaminated food/water/travel
Winter congregating/summer flood
Age <5 not breastfeeding
Older age

Question 5

What infections are most common due to Acid suppression?

Answer 5

Yersinia enterocolitica, Helicobacter pylori, Clostridium difficile, Vibrio cholera, Non-typhoidal Salmonella etc

Question 6

What infections are most common due to Immunosuppression?

Answer 6

Salmonella
Campylobacter
Shigella

Question 7

What are 6 bacterial factors that affect the likeliness of infection?

Answer 7

Adherence/attachment to the GI mucosa
Cellular invasion
Production of exotoxins
Changes in epithelial cell physiology
Loss of brush border digestive enzymes and/or cell death
Increased intestinal motility, net fluid secretion, influc of inflammatory cells and intestinal hemorrhage

Question 8

What is inoculum size?

Answer 8

The median infecting dose required to cause disease in 50% of patients

Question 9

What is diarrhoea?

Answer 9

>3 unformed stools/day
No other cause
Stool holds shape of container
Departure from normal bowel habit
Use Bristol stool chart

Question 10

What is dysentery?

Answer 10

Inflammation of the intestine, particular the colon, causing diarrhea associated with blood and mucus

Question 11

What organisms can cause dysentery?

Answer 11

Shigella

Campylobacter

Question 12

How long is acute gastroenteritis?

Answer 12

<2 weeks

Question 13

What bacteria may cause gastroenteritits?

Answer 13

Yersinia enterocolitica

Question 14

What is gastroenteritis?

Answer 14

An illness causes by eating food contaminated with micro-organisms, toxins, poisons etc

Question 15

What are important history features in gastroenteritis?

Answer 15

Diarrhoea frequency, blood, mucus, time course
Other symptoms
Epidemiology
Food History
Contacts
Age
Comorbidities
Medication history

Question 16

How long is a short incubation time?

Answer 16

1 to 6 hours

Question 17

What food is likely to contain pre-formed toxins?

Answer 17

Starchy foods - reheated rice
Heat resistant spores
Causing Profuse vomiting

Question 18

What is a preformed toxin in food?

Answer 18

Staph Aureus

Bacillus Cereus

Question 19

What are the characteristics of traditional methods of laboratory identification?

Answer 19

Less expensive
Slower
More narrow
Only live bugs grow
Higher quality specimen required

Question 20

What are the characteristics of molecular methods of laboratory identification?

Answer 20

Shorter turn around time
Expensive
Broad range
No sensitivities
Data interpretation

Question 21

What are all stool samples tested for?

Answer 21

Salmonella 
Shigella
Campy
O157
Cryptosporidium
C diff

Question 22

who is my favourite Irish person?

Answer 22

Moya McDevitt

Question 23

Shigella McDevitt

Answer 23

Ella for short

Question 24

What do Shiga-toxin producing e-coli compete with?

Answer 24

Normal bacterial bowel flora

Question 25

Where do the ST e-coli adhere to?

Answer 25

Intestinal epithelial cells

Question 26

What is the process of Shiga toxin e-coli?

Answer 26

Compete with normal bacterial bowel flora,
Adhere to the intestinal epithelial cells, and elaborate Shiga toxin.
Toxins bind to absorptive enterocytes on the luminal surface of the small and large intestines, enter the cell, and irreversibly inhibit protein synthesis, resulting in death of enterocytes.
Shiga toxins can then enter the bloodstream via damaged intestinal epithelium and cause the death of vascular endothelial cells by the same mechanism.
Endothelial cell lysis is accompanied by platelet activation and aggregation, cytokine secretion, vascular constriction contributing to fibrin deposition, and clot formation within the capillary lumen.
Microangiopathy propagates distally as the toxins are carried to the kidneys, causing the clinical syndrome of hematuria and renal failure (HUS). The development of HUS is associated primarily with serotypes that produce Shiga toxin 2.

Question 27

What are the 2 types of Agar used in EHEC?

Answer 27

McConkey agar
Sorbitol McConkey agar
Anti-sera for stereotypes
ELISA indentifies toxins