infectious diarrhoea

Question 1

Define diarrhoea

Answer 1

Fluidity and frequency of stool

Question 2

Define gastro-enteritis

Answer 2

Three or more loose stools/day
inflammation of the small intestine

Question 3

Define dysentry

Answer 3

Inflammation of the large bowel
Bloody stools often containing mucous

Question 4

What stool chart is used to describe consistency and appearance of stool

Answer 4

Bristol stool chart

Question 5

What can cause gastro-enteritis

Answer 5

Contamination of foodstuffs - e.g campylobacter

Poor storage of food

Travel related infection

Person to person spread e.g norovirus

Question 6

What is the most common gastro-enteritis causing bacteria

Answer 6

Campylobacter

Question 7

Which foodborne bacteria causes the most admissions in hospital

Answer 7

salmonella

Question 8

What are the defences against enteric infections

Answer 8

Stomach acidity

Normal gut flora

immunity

Question 9

What can cause the stomach acidity to reduce

Answer 9

Antacids and PPIs

Question 10

What is the common opportunistic bacteria in the gut when the normal flora is dirupted

Answer 10

C difficile

Question 11

What are non inflammatory diarrhoeal pathogen examples

Answer 11

Cholera
Enterotoxigenic E.coli

Question 12

What are the symptoms of non-inflammatory diarrhoeal ilness

Answer 12

Frequent watery stools with little abdo pain
Usually no pain and fever due to no inflammation

Question 13

What is usually the management of non inflammatory diarrhoeal illness

Answer 13

Rehydration therapy

Question 14

How does cholera cause diarrhoea

Answer 14

It releases the cholera toxin which stimulates cAMP which causes increase loss of chlorine from cells - the water then follows the chlorine which leads to it being excreted

Question 15

What are common pathogens which cause inflammatory diarrhoeal illness

Answer 15

Salmonella and campylobacter

Question 16

What are the symptoms of inflammatory diarrhoeal illness

Answer 16

Pain and pyrexia

Question 17

What is the treatment of inflammatory diarrhoeal illness

Answer 17

Antibiotics can be helpful but are not necessary if the patient has a healthy immune system

Rehydration therapy is the most important treatment

Question 18

How long does infective gastro-enteritis usually last

Answer 18

2 weeks

Question 19

What will be seen on examination and in investigations for bacteria causing diarrhoea

Answer 19

Risk of food poisoning

Assess hydration - patients usually dehydrated therefore they will have a postural drop in blood pressure when they stand up, low skin turgor and tachycardia

On bloods, may see signs of inflammation e.g CRP and raised WCC

Question 20

What investigations are done when for patients with suspected bacterial causing gastro-enteritis

Answer 20

Stool culture
blood culture
renal function - increased fluid loss can cause harm to kidneys
blood count - raised WCC
Xray/ CT

Question 21

What is the differential diagnosis for bacterial causing gastro-enteritis

Answer 21

Inflammatory bowel disease
Spurious diarrhoea
carcinoma
Sepsis outside the gut

Question 22

What is spurious diarrhoea

Answer 22

Patient is so constipated that they can only excrete fluid which escapes between the gaps in the constipated bowel

Question 23

What is the treatment for gastro-enteritis

Answer 23

Rehydration :
Oral rehydration with salt/sugar solution
IV saline

Question 24

How long is the incubation period of campylobacter and how long does it take to become cleared

Answer 24

7 days incubation period

Cleared within 6 weeks

Question 25

What is a complication of campylobacter

Answer 25

Post-infection sequelae - developing autoimmune condition after having an immune response to an infection

Question 26

What are the stool investigations done gastro-enteritis

Answer 26

Stool culture - can identify the bacteria and see how it reacts to different forms of bacteria PCR - viral suspicion Immunoassays - if bacterial invasion suspected

Question 27

What is used in culture to specifically look for capmpylobacter

Answer 27

Campylobacter specific agar

Question 28

How is salmonella transmitted

Answer 28

Eating/drinking contaminated food and water Touching infected animals The bacteria lives in the intestines

Question 29

What is the incubation time for salmonella

Answer 29

upto 48 hours

Question 30

What are the symptoms of salmonella gastroenteritis

Answer 30

Inflammatory diarrhoea - therefore pyrexia and abdominal pain with diarrhoea

Question 31

Who is most at risk of salmonella gastroenteritis

Answer 31

Elderly, young, immunocompromised , those taking antacids which reduce stomach acid

Question 32

What does E.coliO157 cause

Answer 32

Characterised by frequent bloody stool Haemolytic uraemic syndrome - haemolytic anaemia, thrombocytopenia and renal failure

Question 33

How is E.coli O157 spread

Answer 33

Contaminated meat or person to perosn

Question 34

What happens in haemolytic-uraemic syndrome

Answer 34

The shigella toxin stimulates platelet aggregation which blocks vessels - the red blood cells try squeeze through which causes haemolysis where they are broken down The uraemia is caused by renal failure when the renal arteries are affected

Question 35

How does staph aureus cause gastroenteritis

Answer 35

release of a toxin

Question 36

What is found in re-fried rice

Answer 36

Bacillus cereus - allows spores of bacillus to open up when the rice is reheated which releases the toxins to the gut

Question 37

What is found is clostridium perfringens found in

Answer 37

Undercooked/ left out meat

Question 38

When are antibiotic indicated in gastroenteritis

Answer 38

Immunocompromised sepsis Chronic illness such as cancer

Question 39

What are the 4 antibiotics that can disrupt the gut flora leading to C difficile invasion

Answer 39

4 C antibiotics Cephalosporin, Co-amoxiclav, ciprofloxacin and clindamycin

Question 40

What is the treatment of C difficle

Answer 40

Metronidazole first line Oral vancomycin

Question 41

What is given as treatment if there is severe colitis caused by C difficile

Answer 41

Oral vancomycin with IV metronidazole

Question 42

How are parasites diagnosed

Answer 42

Microscopy

Question 43

What is giardia duodenalis

Answer 43

Protozoan parasite which is a travellers parasite and is more common in men

Question 44

describe cryptposporidium

Answer 44

Causes diarrhoea, nausea and vomiting with abdo pain Transmitted through infected animals and faeces - contaminated water and food

Question 45

What does entamoeba histolytica cause

Answer 45

Bloody diarrhoea - dysentry Liver abscess

Question 46

How is entamoeba histolytica treated

Answer 46

Metranidazole and luminal agent to flush out the invasion

Question 47

What is rotavirus

Answer 47

Paediatric virus - children version of Norovirus Has a vaccine for rotavirus

Question 48

When is norovirus more common

Answer 48

Winter

Question 49

What is norovirus

Answer 49

Disease which causes diarrhoea and viruses and has common outbreaks in hospital

Question 50

How is norovirus diagnosed

Answer 50

PCR