Infective Diarrhoea

Question 1

define diarrhoea

Answer 1

fluidity and frequency of stools

Question 2

define gastro-enteritis

Answer 2

3 or more loose stools a day plus one of:
> fever
> vomiting
> pain
> blood or mucus in the stools

Question 3

define dysentery

Answer 3

this is inflammation of the bowel resulting in bloody stools

Question 4

what are the defences (both internal and external) against enteric infections?

Answer 4

> hygiene
> stomach acid
> normal flora
> immunity
> gut motility

Question 5

what is the commonest cause of infective diarrhoea?

Answer 5

viruses (campylobacter)

Question 6

what causes the most hospitalised cases of infective diarrhoea?

Answer 6

salmonella

Question 7

what percentage of the population have infective diarrhoea each year?

Answer 7

25%

Question 8

describe the presentation of non-inflammatory diarrhoea

Answer 8

> frequent watery stools

> little abdominal pain

Question 9

true or false:

non-inflammatory diarrhoea is secretory toxin mediated

Answer 9

true

Question 10

how does cholera cause non-inflammatory diarrhoea?

Answer 10

increase cAMP levels and chlorine secretion

Question 11

does E.coli cause inflammatory or non-inflammatory diarrhoea?

Answer 11

non-inflammatory (via enterotoxins)

Question 12

list 3 things you would want to clarify in the history of presenting complaint in a patient with diarrhoea?

Answer 12

> duration of symptoms
frequency
stool quality

Question 13

what are the risk factors for infective diarrhoea?

Answer 13

> contaminated food
> occupation
> travel
> antibiotics
> institutionalisation

Question 14

what should you look for when examining a patient for dehydration?

Answer 14

> pulse
skin turgor
urine output
muscle cramps

Question 15

what investigations could you carry out in infective diarrhoea?

Answer 15

> stool culture (3)
> blood culture
> sigmoidoscopy
> x-ray (distension and tenderness)
> serology
> blood count (haemolysis)
> renal function

Question 16

what is the differential diagnosis for a patient presenting with these symptoms?

Answer 16

> inflammatory bowel disease
carcinoma
sepsis outside the gut
spurious diarrhoea

Question 17

what post infection sequelae can occur in campylobacter infections?

Answer 17

> Gillian barre syndrome

> reactive arthritis

Question 18

what is the principle pathogen in campylobacter infections?

Answer 18

c jejuni (antigens)

Question 19

what is the incubation for campylobacter?

Answer 19

up to 7 days

Question 20

true or false

severe abdominal pain is seen in campylobacter infections?

Answer 20

true

Question 21

in what patients may campylobacter infection become invasive?

Answer 21

in the immunocompromised

Question 22

what is the symptom onset time for salmonella?

Answer 22

<48hrs

Question 23

how long does infective diarrhoea from salmonella usually last?

Answer 23

<10 days

Question 24

what is prolonged carriage of salmonella bacteria associated with?

Answer 24

gallstones

Question 25

true or false | post infective IBS is not associated with salmonella infection

Answer 25

false it is relatively common

Question 26

what symptoms would you expect to see in an E.coli 0157 infection?

Answer 26

frequent bloody stools

Question 27

does the E.coli bacteria enter the blood stream?

Answer 27

no but the shigella like toxin it produces does

Question 28

what syndrome does the SLT produced by E.coli cause?

Answer 28

haemolytic uremic syndrome

Question 29

in what patients in haemolytic uremic syndrome a problem in?

Answer 29

children and the elderly

Question 30

what does haemolytic uremic syndrome cause?

Answer 30

> anaemia > renal failure > thrombocytopenia

Question 31

what is the treatment for E.coli 0157?

Answer 31

supportive (not antibiotics)

Question 32

what is the reservoir for E.coli 0157?

Answer 32

cattle

Question 33

what can complicate a shigella infection?

Answer 33

> haemolytic uremic syndrome | > seizures

Question 34

true or false | shigella is an infection of childhood and travel

Answer 34

true

Question 35

what 3 organisms are the commonest cause for traveller diarrhoea?

Answer 35

> E.COLI > campylobacter > shigella > ?staph aureus??

Question 36

when are antibiotics not indicated in gastroenteritis?

Answer 36

a healthy patient with a non-invasive infection

Question 37

when are antibiotics indicated in gastroenteritis?

Answer 37

``` > immunocompromised > severe sepsis > invasive > valvular heart disease > chronic illness > diabetes ```

Question 38

what does clostridium difficile produce?

Answer 38

enterotoxin and cytotoxin

Question 39

what does cytotoxin produced by c.diff cause?

Answer 39

inflammation and necrosis

Question 40

what is the treatment for c.diff?

Answer 40

> metronidazole > oral vancomycin > stool transplant > surgery?

Question 41

what preventative measures exist for c.diff infections?

Answer 41

> avoiding the 4 C's (clindamycin, cephalosporins, co-amoxiclav, clarithromycin) > isolate symptomatic patients > antimicrobial managing team > hand hygeine

Question 42

how are parasite infections diagnosed?

Answer 42

microscopy

Question 43

what symptoms and signs does giardia lamblia cause?

Answer 43

> smelly diarrhoea > malabsorption > failure to thrive

Question 44

why in a giardia lamblia infection do several stool samples need to be taken?

Answer 44

as cysts are shed intermittently

Question 45

what is used to treat a giardia lamblia infection?

Answer 45

metronidazole

Question 46

true or false | cryptosporidium parvum is found in contaminated water so its main reservoir is not cattle?

Answer 46

false its found in contaminated water and its main reservoir is cattle

Question 47

what can an Entamoeba histolytica infection mimic?

Answer 47

ulcerative colitis

Question 48

what is a long term complication of entamoeba histolytica infection?

Answer 48

liver abscesses

Question 49

how is an entamoeba histolytica infection treated?

Answer 49

metronidazole

Question 50

what is the most common cause of viral diarrhoea?

Answer 50

rotavirus

Question 51

what is the transmission of rotavirus?

Answer 51

faecal oral

Question 52

how is norovirus diagnosed?

Answer 52

PCR