Diarrhoea illness

Question 1

what is gastro-enteritis?

Answer 1

3 or more loose stools per day with accompanying features such as:

• fever
• abdo pain
• bloody stool

Question 2

what is dysentry?

Answer 2

large bowel inflammation with bloody stools

Question 3

what can cause gastroenteritis?

Answer 3

contamination of foodstuffs aka. food poisoning
poor storage of foodstuffs
travel related infection
person to person spread

Question 4

what is the most common cause of gastroenteritis?

Answer 4

viruses

Question 5

what’s the most common bacterial pathogen responsible for gastroenteritis?

Answer 5

campylobacter

Question 6

what are the 4 defences against enteric infections?

Answer 6

hygiene
stomach acid
normal gut flora
immunity

Question 7

how does cholera cause diarrhoea?

Answer 7

increases cAMP levels and Cl secretion

increases secretion of Cl along with Na and K which causes osmotic effect = massive loss of water from the gut

Question 8

how would you initially assess a patient with diarrhoea?

Answer 8

symptom duration: <2 weeks is unlikely
risk of food poisoning (diet, travel)
assess hydration (pulse, skin turgor, postural BP)
features of inflammation: SIRS (fever, raised WCC etc)

Question 9

what investigations would you carry out if someone presented with diarrhoea?

Answer 9

stool bacterial culture 
(molecular or Ag testing)
blood culture
renal function
blood count
abdominal X-ray/ CT if distended/tender abdominal

Question 10

what are the differential diagnoses of gastroenteritis?

Answer 10

IBD
spurious diarrhoea secondary to constipation
carcinoma

Question 11

what is the difference in the onset of campylobacter vs salmonella?

Answer 11

campylobacter has 7 day incubation period whereas salmonella is < 48 hours after exposure

Question 12

what are the 2 most common species of campylobacter that cause gastroenteritis?

Answer 12

C. jejuni

C. coli

Question 13

what is the difference in the stool tests with campylobacter vs salmonella?

Answer 13

campylobacter will be negative after 6 weeks

salmonella may still show positive up to 20 weeks

Question 14

what are the 2 most common salmonella infections?

Answer 14

salmonella enteritis

salmonella typhimurium

Question 15

how is E.coli contracted?

Answer 15

contaminated meat or from person to person spread

Question 16

what toxin does E.coli O157 produce?

Answer 16

shinga toxin

Question 17

what is haemolytic uraemia syndrome and what causes it?

Answer 17

caused by E.coli O157

renal failure, haemolytic anaemia and thrombocytopenia (low platelets)

Question 18

what is the treatment for HUS?

Answer 18

supportive

don’t give antibiotics as this makes the haemolytic worse

Question 19

how is E.coli distinguished from other strains of E.coli?

Answer 19

it is non-sorbitol fermenting

Question 20

what are causes of food poisoning outbreaks?

Answer 20

staph aureus
bacillus cereus
clostridium perfringes

Question 21

when would you give antibiotics for gastroenteritis?

Answer 21

immunocompromised
severe sepsis or invasive infection
chronic illness i.e. malignancy

Question 22

if a patient presents with diarrhoea and had been on co-amoxiclav 2 weeks ago, what is the most likely cause of the diarrhoea?

Answer 22

clostridium difficile

Question 23

what is the treatment for c.diff?

Answer 23

vancomycin

metronidazole

Question 24

what is the treatment for giardia lamblia?

Answer 24

metronidazole

Question 25

what amoeba causes invasive extra intestinal symptoms?

Answer 25

entamoeba histolytica

Question 26

what is the treatment for intestinal disease causes by entamoeba histolytica?

Answer 26

metronidazole + luminal agent to clear colonisation

Question 27

what is the difference between rotavirus and norovirus?

Answer 27

rotavirus found in children under 5 in the winter usually

norovirus is the ‘winter vomiting disease’ found in adults usually in hospitals, schools etc

Question 28

how is norovirus diagnosed?

Answer 28

PCR

Question 29

what is an example of an inflammatory and non-inflammatory diarrhoea illness?

Answer 29

non-inflammatory = cholera
inflammatory = shigella dysentery

Question 30

what are the 3 most common parasites that cause diarrhoea illness?

Answer 30

giardia lambia / duodenalis
cryptosporidium parvum
entamoeba histolytica

Question 31

what investigation should be carried out for diagnosis of a parasitic infection causing diarrhoea?

Answer 31

stool microscopy

Question 32

what investigations should be carried out to exclude c.difficile as the cause of diarrhoea?

Answer 32

toxin testing

Question 33

what investigation should be carried out for diagnosis of a viral infection causing diarrhoea?

Answer 33

viral PCR/ antigen testing

Question 34

what diarrhoea illness is toxic megacolon a complication of?

Answer 34

clostridium difficile

Question 35

what is responsible for the cause of entamoeba histolytic?

Answer 35

foreign travel and poor hygiene

Question 36

what is responsible for the cause of guardia lambia?

Answer 36

contaminated water supply