T11-L9: Gastrointestinal Infections II

Question 1

What is the difference between intoxification and infection?

Answer 1

Intoxification:

- Ingestion of preformed toxin 
- Rapid incubation period - minutes to hours 
- Symptoms include vomiting, nausea, diarrhoea, weakness, resp. failure, numbness sensory/motor dysfunction
- It is not communicable 
- Factors: inadequate cooking, improper handling temperatures

Infection

- Ingestion of bacteria, virus or parasite 
- Slower incubation period - hours to days 
- Symptoms include diarrhoea, nauseas, vomiting, abdominal cramps, fever 
- Onwards transmission is from person to person (faecal oral) 
- Factors include inadequate cooking, cross-contamination, poor hygiene and handwashing procedures

Question 2

What symptoms does S. aureus GI infection cause?

Answer 2

Projectile vomiting and sickness but no fever nor diarrhoea. It has a fats onset 1-4 hours. Works through a heat stable toxin.

Question 3

Is Bacillus cereus toxin mediated or infection mediated?

Answer 3

Toxin - associated with cooked rice and other starchy foods. Produces a heat stable toxin that makes you vomit. Has a quick onset and does not have diarrhoea.

Question 4

What is Clostridium perfingerms associated with?

Answer 4

Meat and meat products - Heat labile toxin that gives diarrhoea and abdominal cramps. It is toxin mediated and reasonably fast.

Question 5

What is the clinical presentation of Clostridium botulinum?

Answer 5

Causes flaccid paralysis. It is a spore forming organism with survival capacity. When it germinates it produces a neurotoxin. The spore will germinate in the gut and a couple days later you get symptoms - blurred vison, respiratory failure and flaccid paralysis. It can be fatal without antitoxins. It is not such a problem now. It is associated with improperly canned food.

Question 6

What is the most common Salmonellae species?

Answer 6

Salmonella nteritidis - It leads to cramps, diarrhoea, fever and myalgia. There is also some nausea and vomiting. It tends to come on 6-8 hours after eating. Salmonella live in birds, poultry and some reptiles.

Question 7

What is the clinical presentation of Shigella?

Answer 7

It is an infection but they also produce an enterotoxin and a shiga toxin. Dysentery as characterised by watery, bloody mucoid stool and abdominal pain. It has a low infective dose. It leads to fluid and electrolyte loss. It is slower to infect and cause a problem (36-72 hours).

Question 8

What is the treatment of E. coli infection?

Answer 8

Treatment is entirely supportive. Do not prescribe antibiotics and antimotility drugs. Advise against NSAIDs due to the potential effect they have on the kidneys.

There are other gastrointestinal E.coli infections. All of them are self-limiting. They do not require any other treatment other than supportive treatment.

Question 9

What is the most common cause of bacterial food illness in the UK?

Answer 9

Campylobacter spp.

This causes a watery diarrhoea, nausea, vomiting, malaise and headache. It produces a heat labile toxin as well as being infective. It is very slow to infect, 2-5 days. They are spread via infective poultry, birds and via the faecal-oral route. We screen for them regularly.

Question 10

What is the treatment for Campylobacter infection?

Answer 10

It is not necessary to give in patients with mild symptoms. But you may need supportive treatments e.g. fluid and electrolytes. There are some groups you would give antibiotics e.g. worsening, symptoms lasting longer. Than a week, immunocompromised, severe symptoms etc. If an antibiotic is indicated with give erythromycin for 5-7 days or Ciprofloxacin.

Question 11

Alongside being ineffective, what toxin does E. coli produce?

Answer 11

Shigella toxin - This can go onto infect the kidney.

Initially it causes water diarrhoea, then bloody diarrhoea. It can then go on to infect the kidneys - AKF, thrombocytopenia, microangiopathic haemolytic anaemia. It has a 10% risk of haemorrhagic colitis and haemolytic uremic syndrome.

Question 12

What virus is a common cause of gastroenteritis in children and has a 5-12 day infectious period?

Answer 12

Rotavirus

Question 13

What is the presentation of adenovirus?

Answer 13

Adenovirus presents with a diarrhoea, vomiting and fever. It has a 5-12 days duration and affects mainly infants and young children.

Question 14

Where do we commonly see outbreaks of astrovirus?

Answer 14

Nursing homes - presents with watery diarrhoea (lasts 2-3 days)

Question 15

What is Calicivirus associated with in adults?

Answer 15

Shellfish

Question 16

What is a common extraintestinal symptom of amoebic dystentery?

Answer 16

Liver abscess - 90% are asymptomatic. In those it causes symptoms, it can present with water diarrhoea, when bloody diarrhoea. They can cause nausea, vomiting, malaise and extraintestinal symptoms

Question 17

What is the treatment for Cryptosporidum parvum infection>

Answer 17

There is no antibiotic necessary in immunocompetent individuals. In the immunocompromised you should treat the underlying condition. Symptoms include watery diarrhoea, weight loss and low grade fever. In the immunocompromised it can give a severe chronic diarrhoea.

Question 18

Give details of Giardia infection.

Answer 18

They cause a foul smelling, water diarrhoea and cramps. It is found in water. It is the most common protozoan parasite of humans. It is seen as a traveller diarrhoea. It has an acute sudden onset and lasts 1-4 weeks. It shows steatorrhea and flatulence, It some people it leads to a chronic relapsing diarrhoea.

Question 19

What is characteristic of a Vibrio cholerae infection?

Answer 19

Rice water stool

Question 20

What drug is Clostridium difficile associated with?

Answer 20

Antibiotics - Treatment therefore means stopping the the predisposing antibiotic and start treatment with vancomycin, or fidaxomicin (metronidazole can be used, but only recommended in certain scenarios). You need infection control and antibiotic stewardship.

Question 21

What bacteria is associated with colorectal cancer?

Answer 21

Streptococcus galloyticus