Diarrhoea

Question 1

What are the bacteria that are sought by routine culture of stools from patients with diarrhoea in the UK?

Answer 1

1) Campylobacter
2) Salmonella enterica
3) E. coli O157
4) Shigella

Question 2

What are some of the non-routine bacteria that can cause diarrhoea?

Answer 2

1) Staph aureus
2) Bacillus cereus
3) Clostridium perfringens

Question 3

What are the commonly detected parasites in stool specimens in the UK?

Answer 3

1) Giardia Lamblia
2) Cryptospiridium Parvum
3) Entamoeba Histolytica

Question 4

What are the commonly detected viruses that cause diarrhoea?

Answer 4

1) Norovirus

Question 5

What is the definition of gasto-enteritis?

Answer 5

3 or more loose stools/day

Question 6

What is the definition of diarrhoea?

Answer 6

Fluidity and frequency of bowel movements

Question 7

What is the definition of dysentery?

Answer 7

Inflammation of the large bowel, including bloody stools

Question 8

What is the most common food borne pathogen?

Answer 8

Campylobacter

Question 9

What pathogen causes the most hospital admissions?

Answer 9

Salmonella

Question 10

What measures are used to prevent the spread of enteric infection?

Answer 10

1 - Hygiene

2- Stomach acidity

3- Normal gut flora

4 - Immunity

Question 11

What are the mechanisms of attachment via which infecting organisms can produce diarrhoea?

Answer 11

1 - Receptors on the gut mucosa

2- Gut mucosa directly

Question 12

What is an example of a bacteria which uses the attachment process to cause diarrhoea?

Answer 12

E. Coli

Question 13

What are the mechanisms of mucosal invasion which can produce diarrhoea?

Answer 13

1- Organism penetrates intestinal mucosa

2- Entry of infecting organism results in production of ‘invasins’

3- More bacteria to enter and produce symptoms of dysentry

Question 14

What is an example of an infectious bacteria which acts via mucosal invasion to produce diarrhoea?

Answer 14

1 - Shigella

2 - Campylobacter

3 - E.Coli

Question 15

What are the mechanisms of toxin production which can produce diarrhoea?

Answer 15

Enterotoxins: - Toxins produced by bacteria that adher to intestinal epithelium, which produce excessive fluid secretion into the bowel lumen - This leads to watery diarrhoea without physically damaging the mucosa

Cholera: - Increases cAMP levels and Cl secretion

Question 16

What are the important components of history taking when dealing with patients with gastro-enteritis?

Answer 16

1 - How long have they had symptoms for, i.e. > 2 weeks means it’s not likely to be gastro-enteritis

2 - Have they been exposed to increased risk of food poisoning? e.g. foreign travel, dietary risk or contact risk

3 - What is the appearance of their stool?.

Question 17

How is hydration assessed in a patient with gastro-enteritis?

Answer 17

1 - Skin Turgor

2 - BP

3 - Pulse

Question 18

How is fluid replacement managed in a dehydrated patient?

Answer 18

• Use rehydration salts which contain a mixture of salts and sugars
• Rehydration can be performed orally or IV

Question 19

What lab tests are performed for patients with gastro-enteritis?

Answer 19

1 - Stool and Blood culture (perform 3 to ensure infection cleared)

2 - Assess renal function

3 - FBC

4 - Abdominal X-ray

Question 20

When should anti-bacterials be used in managing gastro-enteritis?

Answer 20

Antibiotics Indications:

• Immuno-compromised patients
• Valvular heart disease
• Diabetics
• Septic patients with invasive infection
• Chronic illness

Question 21

What are the complications of gastro-enteritis?

Answer 21

1 - Haemolytic Uraemic Syndrome (E.Coli O157)

2 - Irritable bowel syndrome (salmonella)

3 - Guillian-Barre syndrome (campylobacter)

4 - Reactive arthritis

Question 22

What is Haemolytic Uraemic Syndrome?

Answer 22

1 - Caused by E.Coli O157 shiga toxin getting into blood stream

2 - Renal failure, thrombocytopeania and haemolytic anaemia.

3 - Most common in exteremes of age (very young or very old) and immuno compromissed patients.