infectious diarrhoea

Question 1

diarrhoea

Answer 1

fluidity and frequency

Question 2

gastroenteritis

Answer 2

3+ loos stools a day

accompanying feautures: abdo pain, fever, blood/mucous in stool

Question 3

how is gastroenteritis caused

Answer 3

contamination of foodstuffs
poor storage of produce
travel-related infection
person-person spread

Question 4

what is the most common pathogen causing food poisoning

Answer 4

campylobacter

Question 5

which pathogen caused most food poisoning hospital admissions

Answer 5

salmonella

Question 6

defences against enteric infections

Answer 6

hygiene esp hand washing 
stomach acidity 
normal gut flora
gut immunity 
gastric motility 
age

Question 7

different clinical presentations of diarrhoea

Answer 7

non-inflammatory/secretory e.g. cholera

inflammatory e.g. shigella dystentry

mixed e.g. C diff

Question 8

non-inflammatory clinical presentation of diarrhoea

Answer 8

secretory - toxin mediated
frequent watery stools with little abdo pain

rehydration mainstay of therapy

Question 9

mechanism of diarrhoea in cholera

Answer 9

secretory

increased cAMP results in loss of Cl from cells along with Na and K

osmotic effect leads to massive loss of water from gut

Question 10

inflammatory diarrhoea clinical presentation

Answer 10

inflammatory toxin damage and mucosal destruction

pain + fever
bacterial infection/amboeic dystentry

antimicrobials may be appropriate but rehydration alone often sufficient

Question 11

assessing patient with diarrhoea

Answer 11

symptoms and their duration

possible risk of food of poisoning - diet, travel history

assess hydration - postural BP, skin turgor, pulse

features inflammation - fever, raised WCC

Question 12

how is hyponatraemia caused in diarrhoea patients

Answer 12

sodium loss with fluid replacement by hypotonic solutions

Question 13

how is hypokalaemia cuased in diarrhoea patients

Answer 13

K loss in stools

Question 14

investigations for diarrhoea patients

Answer 14

stool culture +/- molecular or Ag testing 
blood culture
renal function 
blood count: neutrophilia, haemolysis 
abdo X-ray/CT is abdo distended/tender

Question 15

treatment of gastroenteritis

Answer 15

oral rehydration with salt/sugar solution

IV saline

Question 16

campylobacter gastroenteritis

Answer 16

up to 7 days incubation

can have severe abdo pain

Question 17

salmonella gastroenteritis

Answer 17

symptoms usually <48hrs post exposure

diarrhoea usually <10days

post infectious irritable bowel common

Question 18

e.coli gastrienteritis

Answer 18

typically have frquent bloody stools

produces shiga toxin

can cause haemolytic-uraemic syndrome

treatment supportive, antib not indicated

Question 19

haemolytic uraemic syndrome

Answer 19

shigella toxin stimulates platelet activation, micro-angiopathy results

characterised by renal failure,, haemolytic anaemia and thrombocytopenia

Question 20

when are antibiotics indicated in gastroenteritis

Answer 20

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

Question 21

routine bacterial culture campylobacter

Answer 21

ieal temp 37-42C
lower 02 than air

commonest cause bacterial food poisoning UK

Question 22

what does c.diff produe

Answer 22

enterotoxin (A) and cytotoxin (B)

is inflammatory

Question 23

how is c.diff treated

Answer 23

metronidazole 
oral vancomycin 
fidaxomicin 
stool transplant 
?surgery

Question 24

preventing c.diff

Answer 24

reduce broad spectrum antib prescribing
avoid 4C antibs
isolate symptomatic patients
wash hands between patients w soap + watre

Question 25

what are the 4C antib

Answer 25

cephalosporins
co-amoxiclav
clindamycin
ciprofloxacin

Question 26

protozoa

Answer 26

1 cell animal

Question 27

helminths

Answer 27

worms

Question 28

how is parasitic diarrhoea diagnosed

Answer 28

microscopy

send stool with request ‘parasites, cysts and ova please’

Question 29

UK parasites causing diarrhoea

Answer 29

giardia lamblia

cryptosporidium parvum

Question 30

giardiasis dirrahoea

Answer 30

abdominal cramps, bloating nausea, bouts of watery diarrhoea, malabsorption, failure to thrive

treat with metronidozole

Question 31

cryptosporidiosis diarrhoea

Answer 31

watery diarrhoea, nausea + vomiting, abdo cramps, low grade fever

no specidic treatment usually required, just rehydration

Question 32

imported diarrhoea causing parasites

Answer 32

entamoeba histolytica

Question 33

viral causes of diarrhoea

Answer 33

rotavirus
adenovirus
norovirus

Question 34

how are rotavirus and adenovirus diagnosed

Answer 34

antigen detection: rapid test

Question 35

how is norovirus diagnosed

Answer 35

PCR