Gastroenteritis Flashcards
what are the main GI symptoms of gastroenteritis?
fever, diarrhoea, abdominal pain, vomiting
what can pathogenic bacteria in the gut do?
- invasion of tissue
2. toxin production
what is the commonest bacteria that causes food poisoning?
campylobacter
what is the species of E coli which is pathogenic and causes food poisoning outbreaks?
E coli 0157
what 2 common causative pathogens of infective gastroenteritis have short incubation periods of 1-6 hours?
staph aureus
bacillus cereus
what 2 common causative pathogens of infective gastroenteritis have medium incubation periods of 12-48 hours?
salmonella
c. perfringens
what 2 common causative pathogens of infective gastroenteritis have long incubation periods of 2-14 days?
campylobacter
E coli 0157
out of staph aures, bacillus cerueus, salmonella, clostridium perfringens, campylobacter and E coli 0157, which are the bacteria which cause bloody stools?
salmonella
c perfringens
campylobacter
E. coli 0157
on average, how long does it take to culture bacteria in the lab?
48 hours
what type of food can campylobacter be found in?
poultry
raw milk
what type of food can salmonella be found in?
poultry, meat, raw egg
what are the antigens on the body of a bacteria called?
O antigens
what are the antigens on the flagella of a bacteria called?
H antigens
what toxin does E coli 0157 produce?
verotoxin
what fatal condition can the verotoxin of E coli 0157 cause if it gets in the blood stream?
haemolytic uraemic syndrome
what is the presentation of haemolytic uraemic syndrome?
abdominal pain fever pallor oliguria petechiae (purple spots) blood diarrhoea
what is petechiae caused by?
small haemorrhages of the blood cessels
if a patient has bloody faeces what must you do?
send a stool culture sapmle
what 3 drugs must be avoided in haemolytic uraemic syndrome and so must be avoided?
antibiotics
anti-motility agents
NSAIDs
who does rotavirus affect?
children less than 3 years old
how is rotavirus spread?
faecal-oral
what are the symptoms of rotavirus?
moderate fever
vomiting
diarrhoea (not bloody)
how do you treat rotavirus?
self-limiting, lasts a week
hydration
what type of vaccine is the rotavirus vaccine?
oral vaccine, live attenuated
when are the rotavirus vaccines given?
2 doses at 2/3 months old
no dose given to babies over 24 weeks old
who does noravirus affect?
all ages
how does noravirus spread?
faecal-oral
how do you diagnose norovirus?
PCR on stool
what is the incubation period for norovirus?
2-4 days
how do you treat nora virus?
self limiting
hydration
what is C dif the result of?
disruption of normal flora
when requesting a stool culture what do all stools automatically get tested for?
salmonella shigella campylobacter E coli 0157 cryptosporidium C dif (if over 15 y/o)
how is C dif spread?
faecal-oral
what is gastroenteritis?
inflammation of stomach or intestines
infective or non-infective cause
why does gastroenteritis cause diarrhoea?
inhibitis nutrient absorption and excessive water and electrolye loss
compare the toxic production of staph aureus/ clostrium perfringens/ bacillius cereus to E coli toxic production?
staph aureus/ C perfringens/ bacillus cereus- preformed toxin
E col- toxin produce in vivo
what are the symptoms of acute enteritis?
fever
diarrhoea
vomiting
abdominal pain
what are the symptoms of acute colitis?
fever
abdominal pain
bloody diarrhoea
what are the symptoms of enteric fever like illness?
fever
rigors
abdominal pain
only little diarrhoea and then constipation
what are the 4 main causes of bloody diarrhoea?
- infection (that’s caused colitis)
- IBD
- malignancy
- ishaemia
what is Guillain-Barre syndrome?
a rare but serious condition where the immune system attacks the peripheral nervous system
-can occur after viral/bacterial trigger
what pathogenic bacteria, known to cause food-poisoning, is Guillain-Barre syndrome highly associated with?
campylobacter infection
what is the main symptom of Guillain-Barre syndrome?
tingling of the feet leads to progressive paralysis of the arms, legs and rest of the body
what does thumb printing show on an abdominal xray?
inflammatory/infective bowel condition
what investigations can be done for suspected gastroenteritis?
stool culture stool toxin stool PCR stool microscopy blood cultures serology FBC U+Es AXR
what are the 4 severity markers of C. dif infection?
(1+ indicates severity)
- temperature above 38.5
- suspicion of pseudomembranous colitis or toxic megacolon or ileus or colonic dilation in AXR above 6cm
- WCC above 15cells x 10^9
- creatinine above1.5x baseline
what are the 4 main intestinal complications of bacterial enteritis?
severe dehydration + renal failure
acute colitis, toxic dilation
post infective irritable bowel
transient secondary lactose intolerance
what are the 6 main extra-intestinal complications of bacterial enteritis?
septicaemia metastatic infection reactive arthritis meningism neurological problems (Guillian Barre extre) HUS
what is the treatment for acute gastroenteritis?
supportive:
oral rehydration and IV fluids
what are the 3 classes of antidiarrhoeal agents?
antimotility agents
antisecretory agents
absorbents
when should you avoid antimotility agents such as opiates and loperamide?
dysenteric symptoms (fever, bloody diarrhoea, abdominal pain)
what is the empirical antibiotic treatment for gastroenteritis if the patient is high risk or has dysenteric symptoms?
ciprofloxacin 500mg BD for 3-5 days
after you have done a stool sample for culture
what patients are high risk in terms of gastroenteritis complications?
immunocompromised
hypochlorhydria
IBD
prosthetic intravascular device
what is hypochlorhdyria?
a condition where the stomach isn’t able to produce enough HCl
what are the main risk factors for C. dif? (apart from antibiotics)
PPI H2-receptor antagonists 65 years old+ chemotherapy chronic renal disease IBD
what antibiotics do you give to a patient with pseudomembranous colitis? (C. dif tested positive)
oral metronidazole (if non-severe)
oral vancomycin (if sever or failure of metronidazole)
what can you give for traveller’s diarrhoea?
early symptomatic treatment:
single dose ciprofloxacin + short term anti-diarrhoeals
what type of infection is amoebiasis?
a protozoal infection
how is amoebiasis spread?
faecal-oral route
what antibiotic is used in the treatment of amoebiasis?
metronidazole
how is giardiasis spread?
cysts n normal drinking water
what is the treatment of cryptosporidiosis?
supportive
antimicrobials are ineffective
how is intestinal amoebiasis diagnosed?
stool microscopy and culture
how is extra-intestinal amoebiasis diagnosed?
serology
what is the definition of acute travellers diarrhoea?
3 loose stools in 24 hours
what is the most common cause of travellers diarrhoa?
E. coli
what is the treatment for acute travellers diarrhoea?
supportive (fluid rehydration)
bloody diarrhoea with systemic upset may warrant treatment:
single dose ciprofloxacin
what is enteric fever causes by?
salmonella typhi or paratyphi
if a patient has sever sepsis with enteric fever what is the treatment?
IV ceftriaxone
ciproflacin is quicker at clearance but organisms are less likely to be sensitive
what are the infective causes of pre-hepatic jaundice?
malaria
HUS (complication of diarrhoeal illness- E coli -157, shigella)
what is the life cycle of intestinal nematodes? (round worms)
- egg ingested
- hatch in small intestine
- invade gut wall into venous system
- reach lungs and break into alveoli
- ascend tracheobronchial tree
- swallowed
- reach gut and develop into adult worms
what is the length of presenting complaints for protozoan infections?
much longer than bacterial infection
what are the 3 main local symptoms of inta-abdominal infection?
pain
tenderness
constipation or diarrhoea
what are the 7 main systemic symptoms of intra-abdominal infection?
fever rigors/chills nausea vomiting anorexia malaise lethargy
what are the 5 major causes for SIRS? (systemic inflammatory response syndrome)
infection trauma burns pancreatitis other inflammatory processes
what is severe sepsis?
acute organ dysfunction secondary to sesis
what is the sepsis 6 protocol?
Take: blood cultures full blood count and lactate measure urine output Give: fluids antibiotics oxygen
what are the 3 main community acquired bacteraemia causes?
Escherichia coli (and other coliforms)
Stephylococcus aureus
Streptococcus pyogenes
what are the 6 main hospital acquired bacteraemia causes?
E coli (and other coliforms( Staph. aureus Coagulase negative Staph Enterococcus spp Pseudomonas aeurignosa Candida spp
what are coliforms?
large, aerobic, gram negative rods which inhabit the large bowel
what is the normal flora of the mouth?
strep viridans neisseria sp anaerobes candida sp staylococci
what is the normal flora of the stomach/duodenum?
usually sterile
few candida and staphylocci
what is the normal flora of the bile ducts?
usually sterile
what is the normal flora of the jejunum?
small numbers of coliforms and anaerobes
what is the normal flora of the colon? (‘faecal flora’)
large numbers of coliformes
anaerobes
enterococcus faecalis
what antibiotics are used for an intra-abdominal infection?
if patient isnt allergic to penicillin
IV amoxicillin + metronidaxole + gentamicin
then step down to
PO co-trimoxazole + metronidazole
(7-10 days)
what antibiotics are used for an intra-abdominal infection? (if patient is allergic to penicillin)
IV vancomycin + metronidazole + gentamicin
then step fown to
PO co-trimoxazole + metronidazole
(7-10 days)
when giving amoxicillin for an intra-abdominal infection what organisms is this antibiotic targetting?
enterococci
when giving gentamicin for an intra-abdominal infection what organisms is this antibiotic targetting?
coliforms
when giving metronidazole for an intra-abdominal infection what organisms is this antibiotics targetting?
anaerobes
what is septic shock?
severe sepsis with hypotension refractory to adequate volume resuscitation or requiring vasopressors or inotropes
