Infectious diarrhoea

Question 1

What is the definition of diarrhoea?

Answer 1

Increased fluidity & frequency

Question 2

What is the definition of gastro-enteritis?

Answer 2

3 or more loose stools/ day

Accompanied with abdominal pain & bloody stools)

Question 3

What occurs with dysentery?

Answer 3

Large bowel inflammation

Bloody stools

Question 4

What type of stool is diarrhoea classified as by the bristol stool chart?

Answer 4

Type 7

Question 5

What are some of the causes of gastro-enteritis?

Answer 5

Contamination of foodstuffs (chicken)
Poor storage of produce
Travel related infections
Person to person spread

Question 6

What is the commonest bacterial pathogen which causes diarrhoea?

Answer 6

Camplyobacter

Question 7

What are the most common causes of infectious diarrhoea?

Answer 7

Campylobacter
Salmonella
E.coli o157

Question 8

What are some of the defences against enteric infections?

Answer 8

Hygiene
Stomach acid
Normal gut flora
Immunity

Question 9

What effect do antacids have on infection?

Answer 9

More at risk of gastro-enteritis due to loss of protective acid

Question 10

What effect do ABIs have on infection?

Answer 10

Increase risk of C. diff & diarrhoea

Question 11

What are the 3 main clinical features of diarrhoea illness?

Answer 11

Non-inflammatory/ secretory
Inflammatory
Mixed

Question 12

What is a secretory (non-inflammatory) form of diarrhoea illness?

Answer 12

Cholera

Question 13

What is an inflammatory cause of diarrhoea illness?

Answer 13

Shigella dysentery

Question 14

What infection demonstrates a mixed picture of diarrhoea disease?

Answer 14

C. diff

Question 15

What is the mechanism of action of secretory toxin-mediated diarrhoea?

Answer 15

Increases cAMP levels & Cl secretion

Osmotic effect leads to massive water loss

Question 16

What is the main treatment of secretory diarrhoea?

Answer 16

Rehydration therapy

Question 17

What are the mechanisms of action of inflammatory diarrhoea disease?

Answer 17

Inflammation & toxin damage leads to mucosal destruction
Pain & fever

Question 18

In a history, when is it unlikely to be infectious diarrhoea?

Answer 18

> 2 weeks duration

Question 19

How can you assess hydration of patient with diarrhoeal disease?

Answer 19

Postural BP
Skin turgor
Pulse

Question 20

What are some of the electrolyte imbalances which can occur in diarrhoea?

Answer 20

Hyponatreamia

Hypokalaemia

Question 21

What investigations could be done in a patient with diarrhoeal disease?

Answer 21

Stool culture
Blood culture
Renal function 
Blood count 
Abdominal Xray

Question 22

What are some of the differential diagnosis of diarrhoeal disease?

Answer 22

Inflammatory bowel disease
Spurious diarrhoea (secondary to constipation)
Carcinoma

Question 23

In what incidence can diarrhoea & fever occur?

Answer 23

Sepsis outside the gut

Question 24

What are some of the treatment options for gastro-enteritis?

Answer 24

Oral rehydration therapy

IV saline

Question 25

What is the commonest cause of gastro-enteritis?

Answer 25

Campylobacter

Question 26

How long is the incubation period of campylobacter gastro-enteritis?

Answer 26

7 days

Question 27

How long does it take for campylobacter to clear from the gut?

Answer 27

6 weeks

Question 28

Is campylobacter invasive/ non-invasive?

Answer 28

Non-invasive

Question 29

What are some of the post-infection diseases which can occur following campylobacter gastro-enteritis?

Answer 29

Guillain-Barre syndrome | Reactive arthritis

Question 30

What are the mechanisms for bacterial culture?

Answer 30

Molecular detection | Antigen detection

Question 31

What are the 2 types of campylobacter which are most commonly the source of infection?

Answer 31

C. jejune (90%) | C. coli (9%)

Question 32

What is the commonest cause of bacterial food poisoning in the UK? What are the main sources?

Answer 32

Campylobacter | Chicken, contaminated milk,

Question 33

When do symptoms of salmonella gastroenteritis occur within?

Answer 33

<48hrs after exposure

Question 34

How long does Salmonella diarrhoeal disease last?

Answer 34

10 days

Question 35

How long could stools be positive for salmonella following disease?

Answer 35

20 weeks

Question 36

What are the most common species of salmonella?

Answer 36

S. enterica | S. bongori

Question 37

How are salmonella species screened in lab?

Answer 37

Lactose non-fermenters (biochemical testing)

Question 38

How can E.coli O157 be contracted?

Answer 38

Contaminated meat | Person-to-person

Question 39

How is E.col O157 typically characterised?

Answer 39

Frequent bloody stool

Question 40

What toxin is produced by E.coli O157?

Answer 40

Shiga toxin

Question 41

What is responsible for E.coli O157 infection?

Answer 41

Toxin - moves into the blood | E.coli remains in the gut

Question 42

What syndrome can the shiga toxin cause?

Answer 42

Haemolytic -uraemic (HUS) syndrome

Question 43

What is NOT recommended in the treatment of E.coli O157?

Answer 43

ABIs - causes increased lysis of the bug therefore increases the risk of toxin release

Question 44

What does shiga toxin stimulate in the blood?

Answer 44

Toxin stimulates platelet activation | Micro-angiopathy

Question 45

What other forms of E.coli cause diarrhoea?

Answer 45

Enteroinvasive Enteropathogenic Enterotoxic (travellers diarrhoea)

Question 46

How can E.coli O157 be distinguished from other strains?

Answer 46

Non-sorbitol fermenting

Question 47

What are some of the occasional cause of food poisoning outbreaks?

Answer 47

S. aureus Bacillus cereus (rice) C. perfringens (meat)

Question 48

When could ABIs be used in gastroenteritis?

Answer 48

Immunocomprised Severe sepsis or invasive infection Chronic illness eg malignancy

Question 49

When are ABIs not advised in gastroenteritis?

Answer 49

In an healthy patient with non invasive infection

Question 50

What ABIs are associated with C diff diarrhoea infection?

Answer 50

4Cs : cephalosporin, co-amoxiclav, clindamycin, ciprofloxacin

Question 51

What are the toxins produced by C. Diff?

Answer 51

Enterotoxin | Cytotoxin

Question 52

What are the main treatments for C diff infection?

Answer 52

Metronidazole | Oral Vancomycin

Question 53

Which ABI is normally administered IV but used orally in C. diff infection?

Answer 53

Vancomycin

Question 54

What important actions should be taken with a patient with C. diff?

Answer 54

Isolate symptomatic patient Wash hands between patients Contact precautions

Question 55

How should you manage C. diff?

Answer 55

Stop precipitating ABIs | Oral metronidazole or vancomycin

Question 56

What are some examples of parasites?

Answer 56

Protozoa or helminths

Question 57

How are parasites usually diagnosed?

Answer 57

Microscopy | Stool sample - parasites, cysts & ova (P,C,O)

Question 58

What symptoms are observed in parasite disease (G. lambia)?

Answer 58

Diarrhoea Malabsorption Gas Failure to thrive

Question 59

How are parasites transmitted?

Answer 59

Direct contact with animals or people | Contaminated water/ food

Question 60

How are parasites treated?

Answer 60

Metronidazole

Question 61

What does entamoeba histolytica cause?

Answer 61

Amoebic dysentery

Question 62

What parasite causes liver abscess?

Answer 62

Entamoeba histolytica (anchovy pus)

Question 63

What are the different types of viral diarrhoeal disease?

Answer 63

Rotavirus Norovirus Adenovirus

Question 64

What population does Rotavirus usually affect?

Answer 64

Children under 5 yrs

Question 65

When did cases of rotavirus decrease significantly?

Answer 65

Introduction of vaccination

Question 66

Where can outbreaks of norovirus usually occur?

Answer 66

Institutions, hospitals, community & cruise ships

Question 67

How can norovirus be diagnosed?

Answer 67

PCR

Question 68

How can spread of norovirus be controlled?

Answer 68

Strict infection control