Intra-abdominal Infection Flashcards
colonisation definition?
presence of microbe in human without inflammatory response (there but not causing issue)
infection?
inflammation due to a microbe
bacteraemia?
presence of viable bacteria in blood
sepsis?
systemic inflammatory response to infection
life-threatening organ dysfunction caused by a dysregulated host response to infection
septic shock?
subset of sepsis with circulatory and cellular/metabolic dysfunction associated with a higher risk of mortality
what can cause an infection to become problematic?
unusual host response (age, immunosuppression, co-morbidity, drugs etc)
unusual microbe response (virulence expression latency, intracellular predilection for certain sites)
site of infection (worse if deep seated infection - cardio, bone, joints, occult)
where can defence defects occur in the host?
surface mucosal barrier complement antibodies B cells macrophages cytokines T cells NK cells (area of defect depends on illness - eg alcoholism, malnutrition etc)
what do phagocytes target?
bacteria
fungi
what do T cells target?
viruses
fungi
protozoa
what do B cells and antibodies target?
bacteria
viruses
what do eosinophils target?
fungi
protozoa
worms
what di mast cells target?
worms
what does complement target?
bacteria
what organisms are usually found in peritoneal cavity?
none
should be sterile
leakage of bowel contents etc results in peritonitis
what can cause leakage of bowel contents?
perforated duodenal ulcer
perforated appendix
perforated diverticular
perforated tumour
what is SOFA score?
sequential organ function assessment (sepsis related) takes into account - resp - coagulation - liver function - cardio - CNS - renal each scored from 0-4 (0=best, 4=worst)
qSOFA?
shortened SOFA scoring screens for outcome (not diagnosis) - RR>22 - systolic BP < 100 - altered GCS 0/3 = <1% mortality 1/3 = 2-3% mortality 2+/3 = >10% mortality
SIRS criteria?
when 2 or more of the following are present
- temp >38 or <36
- HR > 90
- RR >20 or PaCO2 < 32 (4.3kPa)
- WCC > 12000 (>12x10^9/L)
how does infection severity progress?
colonisation > infection > SIRS > sepsis > severe sepsis > septic shock
(mortality increases)
what is SIRS?
systemic inflammatory response syndrome
whole body inflammatory response
non-specific clinical response including >2 of the following
- temp >38 or <36
- HR >90
- RR >20
- WCC >12000 or <4000 or >10% immature neutrophils
what can cause SIRS?
infection trauma burns pancreatitis other insults
how is sepsis different to SIRS?
sepsis = SIRS with a presumed or confirmed infectious process
what is septic shock?
sepsis + signs of at least 1 acute organ dysfunction
what organisms generally cause community infection?
E coli (urine, abdomen) strep pneumoniae (resp) staph aureus (usually MSSA - skin)
what organisms generally cause hospital infection?
E coli (catheter or abdomen) staph aureus (usually MRSA - line or wound related) CNS (line/prosthesis related) enterococci (urine, wound, line) klebsiella (urine, wound) pseudomonas
supportive management in infection syndrome?
fluids analgesia VTE prophylaxis oxygen control electrolyte balance need for transfusion
when might surgery be needed to support infection?
exploration
incision-excision and drainage etc
what are coliforms?
E coli and similar bugs that inhibit large bowel
e.g klebsiella, proteus, Enterobacter, serratia etc
rod shaped gram -ve bacteria
example of strict aerobe?
pseudomonas
examples of aerobes?
staph
strep
enterococci
coliforms (majority of human pathogens)
examples of strict anaerobes?
clostridium
bacteroides
anaerobic cocci
(Present in large numbers in large bowel)
normal mouth flora?
strep viridans Neisseria (gram -ve cocci) anaerobes candida (few) staph
normal stomach/duodenum flora?
usually sterile
can have a few candida and staph which may survive acidic environment
normal flora of jejunum?
small numbers of coliforms and anaerobes
normal flora of colon (faecal flora)?
large numbers of coliforms, anaerobes and enterococcus faecalis
normal flora of bile ducts?
sterile
how long are antibiotics given in sepsis?
usually 10-14 days
4-6 weeks if complicated
empirical treatment of intra-abdominal infections?
amoxicillin + gentamicin + metronidazole
amox = strep and enterococcus
gent = aerobic coliforms
met = anaerobes
how are abscesses managed?
large abscess has no blood supply so antibiotic wont reach it
small abscesses can be treated with antibiotics but large ones need incision and drainage
antibiotic for coliforms?
gentamicin
antibiotics for anaerobes?
metronidazole
antibiotic for enterococcus?
amoxicillin
intra-abdominal infection empirical management if penicillin allergic?
cotrimoxazole + gentamicin + metronidaole
what antibiotics are used for prophylaxis in GI/hepatobiliary surgery?
gentamicin + metronidazole
what is the risk with gentamicin?
renal damage (nephrotoxic)
how is nephrotoxicity risk managed in gentamicin use?
limit duration to 72 hrs after which ID/micro approval is needed
limit duration to 24 hrs if concerns of renal function
monitor renal function daily
clear exclusion criteria also exists
check levels twice a day
dosing in gentamicin?
dose per weight?
ensure correct dosing in overweight patients
max dose = 600mg
