Infective Diarrhoea Flashcards
define diarrhoea
fluidity and frequency of stools
define gastro-enteritis
3 or more loose stools a day plus one of: > fever > vomiting > pain > blood or mucus in the stools
define dysentery
this is inflammation of the bowel resulting in bloody stools
what are the defences (both internal and external) against enteric infections?
> hygiene > stomach acid > normal flora > immunity > gut motility
what is the commonest cause of infective diarrhoea?
viruses (campylobacter)
what causes the most hospitalised cases of infective diarrhoea?
salmonella
what percentage of the population have infective diarrhoea each year?
25%
describe the presentation of non-inflammatory diarrhoea
> frequent watery stools
> little abdominal pain
true or false:
non-inflammatory diarrhoea is secretory toxin mediated
true
how does cholera cause non-inflammatory diarrhoea?
increase cAMP levels and chlorine secretion
does E.coli cause inflammatory or non-inflammatory diarrhoea?
non-inflammatory (via enterotoxins)
list 3 things you would want to clarify in the history of presenting complaint in a patient with diarrhoea?
> duration of symptoms
frequency
stool quality
what are the risk factors for infective diarrhoea?
> contaminated food > occupation > travel > antibiotics > institutionalisation
what should you look for when examining a patient for dehydration?
> pulse
skin turgor
urine output
muscle cramps
what investigations could you carry out in infective diarrhoea?
> stool culture (3) > blood culture > sigmoidoscopy > x-ray (distension and tenderness) > serology > blood count (haemolysis) > renal function
what is the differential diagnosis for a patient presenting with these symptoms?
> inflammatory bowel disease
carcinoma
sepsis outside the gut
spurious diarrhoea
what post infection sequelae can occur in campylobacter infections?
> Gillian barre syndrome
> reactive arthritis
what is the principle pathogen in campylobacter infections?
c jejuni (antigens)
what is the incubation for campylobacter?
up to 7 days
true or false
severe abdominal pain is seen in campylobacter infections?
true
in what patients may campylobacter infection become invasive?
in the immunocompromised
what is the symptom onset time for salmonella?
<48hrs
how long does infective diarrhoea from salmonella usually last?
<10 days
what is prolonged carriage of salmonella bacteria associated with?
gallstones
true or false
post infective IBS is not associated with salmonella infection
false it is relatively common
what symptoms would you expect to see in an E.coli 0157 infection?
frequent bloody stools
does the E.coli bacteria enter the blood stream?
no but the shigella like toxin it produces does
what syndrome does the SLT produced by E.coli cause?
haemolytic uremic syndrome
in what patients in haemolytic uremic syndrome a problem in?
children and the elderly
what does haemolytic uremic syndrome cause?
> anaemia
renal failure
thrombocytopenia
what is the treatment for E.coli 0157?
supportive (not antibiotics)
what is the reservoir for E.coli 0157?
cattle
what can complicate a shigella infection?
> haemolytic uremic syndrome
> seizures
true or false
shigella is an infection of childhood and travel
true
what 3 organisms are the commonest cause for traveller diarrhoea?
> E.COLI
campylobacter
shigella
?staph aureus??
when are antibiotics not indicated in gastroenteritis?
a healthy patient with a non-invasive infection
when are antibiotics indicated in gastroenteritis?
> immunocompromised > severe sepsis > invasive > valvular heart disease > chronic illness > diabetes
what does clostridium difficile produce?
enterotoxin and cytotoxin
what does cytotoxin produced by c.diff cause?
inflammation and necrosis
what is the treatment for c.diff?
> metronidazole
oral vancomycin
stool transplant
surgery?
what preventative measures exist for c.diff infections?
> avoiding the 4 C’s (clindamycin, cephalosporins, co-amoxiclav, clarithromycin)
isolate symptomatic patients
antimicrobial managing team
hand hygeine
how are parasite infections diagnosed?
microscopy
what symptoms and signs does giardia lamblia cause?
> smelly diarrhoea
malabsorption
failure to thrive
why in a giardia lamblia infection do several stool samples need to be taken?
as cysts are shed intermittently
what is used to treat a giardia lamblia infection?
metronidazole
true or false
cryptosporidium parvum is found in contaminated water so its main reservoir is not cattle?
false its found in contaminated water and its main reservoir is cattle
what can an Entamoeba histolytica infection mimic?
ulcerative colitis
what is a long term complication of entamoeba histolytica infection?
liver abscesses
how is an entamoeba histolytica infection treated?
metronidazole
what is the most common cause of viral diarrhoea?
rotavirus
what is the transmission of rotavirus?
faecal oral
how is norovirus diagnosed?
PCR
