IC17b PR3151 CDI Flashcards
what is clostridiodes difficile? include:
type of pathogen
route of transmission
gram positive anaerobic spores
spread by fecal oral contact
causes diarrhoea and colitis
toxigenic strain contains toxin A and B
what is the clinical spectrum of clostridiodes difficile?
can be asymptomatic carriers to fulminant disease
examples of how does c.diff spread?
fecal oral contact
hands of HCW
rooms of patients with CDI
what is the pathogeneiss of c.diff?
spread through fecal oral, facilitated by antibiotic use which removes the protective function of the colonic flora
- c.diff releases toxin A and B (B is more important ) and causes inflammation and diarrhoea.
some patients may develop antibodies (esp carriers)
what are the risk factors for c.diff?
BREAKDOWN
1) patient-related
* advanced age >65yo
* multiple/severe comorbidities
* immunosuppression
* history of CDI
2) medication-related
* use of ABX
* use of gastric acid suppressive therapy
3) hospital-related
* tube feeding
* GI surgery
* prior hospitalisation (1year)
* duration of hospitalisation
* residence in nursing home/LTC
which antibiotics increase risk for c.diff?
how long does risk last
all abx increase risk
in order
1) clindamycin
2) 3rd and 4th gen cephalosporins
3) FQ
risk goes up to 12 weeks after stopping abx
which antibiotics decreases risk for c.diff?
doxycycline and tigecycline shown to have protective function and active through toxin production inhibition
also has minimal effects on gut flora
c.diff infection control and protection measures? (non phx)
1) isolation
- isolate patients with CDI in private room, prioritise those with stool/fecal incontinence
2) hand hygiene
3) environmental cleaning
- use sporicidic agents
4) ASP
(drug) c.diff infection control and protection measures? (unknown efficacy)
acid suppression
- discontinue uncessary PPIs
probitics
- not routinely recommended
cardinal clinical presentation of c.diff?
watery stools ≥3loose stools in 24h
(for mild) clinical presentation of c.diff?
diarrhoea, abdominal cramp
(for moderate) clinical presentation of c.diff?
fever diarrhoea nausea malaise
abdo cramp and distension
leukocytosis
hypovolemia
(for severe) clinical presentation of c.diff?
fever diarrhoea
diffused abdo cramp and distension
wbc≥15x10^9 or scr ≥133umol/L (1.5mg/dL)
(for fulminant) clinical presentation of c.diff?
hypotension, shock
ileus
megacolon
diagnosis criteria for c.diff?
1) presence of ≥3 unformed stools in 24 hours
OR radiographic evidence of ileus/toxic megacolon
AND
2) positive stool test result for c.diff or its toxins (for symptomatic pts only because does not distinguish infection from colonisation)
OR colonoscopic/histopathologic evidence of pseudomembranous colitis
stool test requirements for c.diff?
X asymptomatic
limited to diarrhoea pts with ≥3 stools/24h
confirm pt no laxative in last 48h
do not repeat if <7 days
do not repeat test to document cure
treatment principles for c.diff?
Do not treat asymptomatic patients with a positive C. difficile test
- Confirm symptoms consistent with CDI exist prior to prescribing therapy
If possible, discontinue any antibiotic therapy not specifically treating CDI
If additional antibiotic therapy is necessary
Select the narrowest agent possible
Avoid agents with a strong association with CDI
treatment for initial episode of c.diff? (first-line) (nonsevere)
po vancomycin 125mg QD x10 days (14 if unresolved)
treatment for initial episode of c.diff? (alternative) (nonsevere)
PO metronidazole 400mg TDS x10 days (14 if unresolved)
definition of non-severe c diff?
WBC <15x10^9/L
SC<133umol/L (1.5mg/dL)
treatment for initial episode of c.diff? (first-line) (severe)
po vancomycin 125mg QDx10 days (14 if unresolved)
definition of severe c diff?
WBC ≥15x10^9/L
SC≥133umol/L (1.5g/dL)
treatment for initial episode of c.diff? (first-line) (fulminant)
IV metronidazole 500mg Q8
+
PO vancomycin 500mg QD
+/-
PR vancomycin 500mg QD
x10 days (14 if unresolved)
definition of fulminant c diff?
hypotension
or
ileus
or
megacolon
definition of recurrent c.diff?
resolution -> sudden reappearance
around 30% have recurrence
risk factors for recurrent c.diff?
1) administration of other abx during or after tx
2) defective humeral response against CDiff toxins
3) advanced age
4) severe underlying disease
5) continued use of PPis
first treatment for recurrent c.diff?
If Vanco for initial:
PO Vancomycin tapered/pulsed
(125mg QDS x 10-14 days, 125mg BD x 7 days, 125mg daily x 7 days, 125mg every 2-3 days x 2-8 weeks) FYI DOSING
OR
if metro for initial:
PO Vancomycin 125mg QDS x 10 days
Fidaxomine 200mg BD x10
Fidaxomine 200mg BD x5 + 200mg BD EOD x 20
c diff monitoring?
resolve in 10 days, otherwise extend for another 4 days of tx
additional diagnostics or consider escalation if poor response
special properties of metronidazole in CDI?
IV metronidazole able to undergo enterohepatic circulation back to the gut, thereby affecting colonic flora
generally most iv wont re-enter the gut.
