Infections: Gastroenteritis

Question 1

Acute traveller’s diarrhoea is most commonly caused by which bacteria? [1]

Answer 1

enterotoxigenic E. coli

Question 2

What is the most common cause of viral gastroenteritis in children? [1]

Answer 2

rotavirus

Question 3

What is the second most common cause of traveller’s diarrhoea? [1]

Answer 3

Camopylobacter jejuni

Question 4

How do you treat Campylobacter jejuni infection? [3]

Answer 4

• Clathromycin (1st line)
• Azithromycin
• Ciprofloxacin

Question 5

A patient has recently eaten fried rice left at room temperature. They are reported vomitting and then diarrhoea.

What is the most likely pathogen causing these symptoms? [1]

Answer 5

Bacillus cereus

Question 6

How can you differentiate between Bacillus cereus causing diarrhoea compared to other infective agents? [1]

Answer 6

Bacillus cereus causes vomiting for 5hrs; then diarrhoea for 8hrs

Question 7

What syndrome can Shigella cause? [1]
Name two treatments [2]

Answer 7

haemolytic uraemic syndrome:

Treatment of severe cases is with azithromycin or ciprofloxacin.

Question 8

A patient presents with diarrhoea, right sided abdominal pain and fever.
What is the most likely cause of infection? [1]
What is a differential diagnosis? [1]

Answer 8

Yersinia enterocolitica: diarrhoea, right sided abdominal pain and fever.

Right sided abdominal pain is caused by mesenteric lymphadenitis (inflammation in the intestinal lymph nodes): appears like appendicitis}

Question 9

Which parasite is found in the small intestines of mammals and causes diarrhoea via a faecal-oral transmission? [1]

Answer 9

Giardia lamblia

Question 11

How do you treat Giardia lamblia? [2]

Answer 11

tinidazole or metronidazole

Question 12

A faecal stool sample was sent, and the results this morning are as follows:

C. difficile toxin -ve
C. difficile antigen +ve

What is the next step in the management of this patient? [1]

Explain your answer [1]

Answer 12

C. difficile antigen positivity only shows exposure to the bacteria, rather than current infection

If the toxin is positive, it means the bacteria is actively replicating and is likely the cause of the diarrhoea.

If the antigen is positive in isolation, it merely means the bowel is colonised with C. difficile, and not necessarily causing diarrhoea.

Reassure and continue monitoring symptoms

Question 13

Which drug classes are risk factors for C. diff infection? [2]

Answer 13

Antibiotics
PPIs

Question 14

The [] is key in determining the severity of C. difficile infection

Answer 14

The white cell count is key in determining the severity of C. difficile infection

Question 15

Which antibiotics are most likely to cause C. difficile infection? [2]

Answer 15

Second and third-generation cephalosporins are now the leading cause of C. difficile.

Clindamycin is historically associated with causing C. difficile but the aetiology has evolved significantly over the past 10 years.

C. difficile: think C!

Question 16

Which overall type of pathogen most commonly causes gastroenteritis in children? [1]

Name the three most common pathogens [3]

Answer 16

Viral gastroenteritis is most common. It is highly contagious. Common causes are:
* Rotavirus
* Norovirus
* Adenovirus is a less common cause and presents with a more subacute diarrhoea.

Question 17

Describe the relationship between E. coli and haemolytic uraemic syndrome (HUS) [2]

Answer 17

E. coli 0157 produces the Shiga toxin: This causes abdominal cramps, bloody diarrhoea and vomiting.
- The Shiga toxin destroys blood cells and leads to haemolytic uraemic syndrome (HUS).

Question 18

Describe a risk factor for HUS [1]

Answer 18

The use of antibiotics increases the risk of haemolytic uraemic syndrome, therefore antibiotics should be avoided if E. coli gastroenteritis is considered.

Question 19

Eating raw or undercooked pork OR spread through contamination with the urine or faeces of other mammal such as rats and rabbits.

This refers to gastroenteritis can caused infection by which pathogen? [1]

Describe the presentation [4]

Answer 19

Yersinia Enterocolitica
- Yersinia most frequently affects children
- causing watery or bloody diarrhoea
- abdominal pain
- fever
- lymphadenopathy

Question 20

What is the incubation period like of Yersinia Enterocolitica like? [1]

How long does infection last? [1]

Answer 20

Incubation is 4 to 7 days and the illness can last longer than other causes of enteritis with symptoms lasting 3 weeks or more.

Question 21

Describe how Shigella is spread [1]

What is the incubation period like? [1]

What is the treatment like? [2]

Answer 21

Shigella is spread by faeces contaminating drinking water, swimming pools and food.

The incubation period is 1 to 2 days and symptoms usually resolve within 1 week without treatment.
- Treatment of severe cases is with azithromycin or ciprofloxacin.

Question 22

Describe the presentation of Shigella gastroenteritis [3]

Answer 22

It causes bloody diarrhoea, abdominal cramps and fever. Shigella can produce the Shiga toxin and cause haemolytic uraemic syndrome.

Question 23

What is a key indicator that a patient is suffering from H.U.S? [2]

Answer 23

Blood diarrhoea and AKI symptoms

Question 24

How do you distinguish between bacterial and viral gastroenteritis?

Answer 24

Bacterial gastroenteritis:
- usually presents with high fever and severe diarrhoea, which is commonly bloody.

Viral gastroenteritis is a self-limiting condition which lasts < 14 days. The most common symptoms include:
- Acute diarrhoea
- Vomiting (80%)
- Mild fever (40%)
- A short viral prodrome may occur before the onset of diarrhoea, consisting of mild fever and nausea or vomiting.

NB: A temperature >39°C in adults or >38°C in children under 3 months old should raise suspicion of bacterial pathology.

Question 25

Describe the typical presentation of:
- Escherichia coli [3]
- Giardiasis [1]
- Cholera [2]

Answer 25

Describe the typical presentation of: [3]

Escherichia coli:
* Common amongst travellers
* Watery stools
* Abdominal cramps and nausea

Giardiasis:
- Prolonged, non-bloody diarrhoea

Cholera:
* Profuse, watery diarrhoea
* Severe dehydration resulting in weight loss

Question 26

Describe the typical presentation of:
- Shigella [2]
- Staph aureus [2]
- Campylobacter [3]

Answer 26

Question 27

Describe the typical presentation of:
- Bacillus cereus [2]
- Amoebiasis [2]

Answer 27

Question 29

Incubation period
1-6 hrs: [2]
12-48 hrs: [2]
48-72 hrs: [2]
> 7 days: [2]

Answer 29

Incubation period:
1-6 hrs: Staphylococcus aureus, Bacillus cereus
12-48 hrs: Salmonella, Escherichia coli
48-72 hrs: Shigella, Campylobacter
> 7 days: Giardiasis, Amoebiasis

Question 30

What are the treatments for the following: [+]
- E. coli
- Gardiosis
- Cholera
- Shigella
- Staph aureus
- Campylobacter
- Bacillus cereus
- Ameobiosis

Answer 30

Escherichia coli
- Gram Negative Rod
- Mx - Self Limiting

Giardiasis
- Flagellate Protozoan
- Mx - Metronidazole

Cholera
- Gram Negative Curved Rod
- Mx - 1. Doxycycline or 2. Ciprofloxacin

Shigella
- Gram Negative Rod
- Mx - 1. Ciprofloxacin or 2. Azithromycin

Staphylococcus aureus
- Gram + Cocci - Clustered (Grapes)
- Mx - Self Limiting

Campylobacter
- Gram Negative ‘Spiral’ Curved Rod
- Mx - Clarithromycin

Bacillus cereus
- Gram + Rod
- Mx - Mild = Self Limiting OR Severe = Vancomycin

Amoebiasis
- Mx - Metronidazole + Diloxanide Furoate (Intraluminal Agent)