Infectious Diarrhoea

Question 1

What is the definition of gastroenteritis?

Answer 1

Clinical diagnosis of stools three or more daily with associated symptoms like fever and abdominal pain.

Question 2

What is the name of the chart used to categorise the consistency of stools?

Answer 2

Bristol Stool Chart

Question 3

What are four methods of getting gastro enteritis?

Answer 3

Person to person spread
Contaminated food that isn’t cooked properly
Leaving food out at the wrong temperature
Travel related infections

Question 4

What are the most common causes of gastroenteritis?

Answer 4

Viruses are the most common cause

Campylobacter is the most common bacterial cause

Question 5

What are four defences against enteric infections?

Answer 5

Good hygiene
Acid in stomach-so if on antacids more likely to get an infection
Immune system-if immunocompromised more likely to get an infection
Normal gut flora

Question 6

What are two types of secretory (non inflammatory) diarrhoea?

Answer 6

Cholera-caused by the toxins that are secreted by the cholera virus that increase cAMP and chloride secretion which affects the osmotic gradient and they get a large volume of fluid loss.
Traveller’s diarrhoea- enterotoxigenic E. Coli
They get frequent watery diarrhoea and little abdominal pain. Often present with hypovolaemic shock.

Question 7

What are the features of inflammatory diarrhoea?

Answer 7

Inflammatory toxin damage and mucosal destruction.
Get pain and fever.
Bacterial and amoebic dysentery.

Question 8

What are some signs of dehydration in a child?

Answer 8

Sunken fontanelles
Sunken eyes
Skin turgor
Sunken abdomen
Dry mouth and eyes
Few/no tears

Question 9

What investigations should be done in a patient with diarrhoea?

Answer 9

Stool culture
Molecular and antigen testing
Full blood count (WBC, and haemolysis)
Blood cultures
Renal Function
Abdominal X-Ray/CT if the abdomen is distended as higher risk of perforation if dilatation of bowel (>9cm at caecum)

Question 10

What is the treatment of gastro enteritis?

Answer 10

IV saline

Oral rehydration with glucose/salt solution

Question 11

What are two main Campylobacter species?

Answer 11

C. Jejuni

C. Coli

Question 12

What is a Campylobacter species that causes extra intestinal infections?

Answer 12

C. Fetus

Question 13

What is the incubation period for Campylobacter and how long does it take to clear the system?

Answer 13

7 days

Takes 6 weeks to clear from the system

Question 14

What are some sources of campylobacter infection?

Answer 14

Birds (raw chicken)
Young animals-sheep or cattle
Drinking contaminated water
Visiting Africa/foreign travel

Question 15

What are some post infection complications from Campylobacter infections?

Answer 15

Arthritis

Guillain Barre Syndrome

Question 16

What is the incubation period for Salmonella and how long does it take to clear the system?

Answer 16

10 day incubation period

20 week clearance time

Question 17

What is a post infection complication from Salmonella infection?

Answer 17

IBS

Question 18

What are two non typhoidal species of Salmonella>

Answer 18

S. enterica

S. bongori

Question 19

Describe the bacteria salmonella

Answer 19

Gram negative anaerobic bacilli

Question 20

What do the Salmonella Typhoid species cause in the body?

Answer 20

Enteric fever, not gastroenteritis

Question 21

What are two salmonella typhoid species?

Answer 21

S, typhi

S. paratyphi

Question 22

What is haemolytic uraemia?

Answer 22

Haemolytic anaemia
Renal Failure
Thrombocytopenia

Question 23

How can E. coli cause haemolytic uraemia?

Answer 23

E. coli produces the Shig toxin (similar to the one produced by shigella spp) that gets into the bloodstream and causes HUS (bacteria itself doesn’t get into the blood)

Question 24

What are five symptoms of HUS?

Answer 24

Lethargy
Seizures
Abdominal pain
Bloody Diarrhoea
Fever

Question 25

When are antibiotics indicated in gastroenteritis?

Answer 25

Sepsis or invasive infection Immunocompromised Chronic Illness (malignancy)

Question 26

What are the possible treatments for C. Diff infection?

Answer 26

``` metronidazole oral vancomycin Fidaxomicin (new and expensive) Stool transplants surgery may be required ```

Question 27

What are the four 'C' antibiotics that commonly precipitate C. diff infection?

Answer 27

Cephalosporin Co-amoxiclav Ciprofloxacin Clindamycin

Question 28

How are parasites in stools diagnosed?

Answer 28

Send away a stool culture and ask for parasites, cysts and ova.

Question 29

What is an example of a protozoa causing gastroenteritis?

Answer 29

Giardia duodenalis

Question 30

How is Giardia spread?

Answer 30

Via animals and other people | Via infected food or water

Question 31

What are the symptoms of giardia and how is it treated?

Answer 31

``` Diarrhoea Failure to thrive Gas Malabsorption Treat with metronidazole ```

Question 32

What is the typical presentation of rotavirus?

Answer 32

Children under five in the winter getting ill | Diagnosed via stool antigen

Question 33

How is norovirus diagnosed?

Answer 33

PCR

Question 34

What is the presentation of Entamoeba histolytica?

Answer 34

``` amoebic dysentery (instestinal amoebiasis) Invasive extraintestinal amoebiasis (liver/pleuropulmonary/brain abscess) – months/years later – usually no bowel symptoms ```

Question 35

How is Entamoeba histolytica diagnosed?

Answer 35

Hot stool and serology. Trophosites and cysts seen in sample

Question 36

How is Entamoeba histolytica treated?

Answer 36

Metronidazole and luminal agent