IC17b PR3151 CDI

Question 1

what is clostridiodes difficile? include:
type of pathogen
route of transmission

Answer 1

gram positive anaerobic spores
spread by fecal oral contact
causes diarrhoea and colitis
toxigenic strain contains toxin A and B

Question 2

what is the clinical spectrum of clostridiodes difficile?

Answer 2

can be asymptomatic carriers to fulminant disease

Question 3

examples of how does c.diff spread?

Answer 3

fecal oral contact
hands of HCW
rooms of patients with CDI

Question 4

what is the pathogeneiss of c.diff?

Answer 4

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)

Question 5

what are the risk factors for c.diff?

Answer 5

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

Question 6

which antibiotics increase risk for c.diff?

how long does risk last

Answer 6

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

Question 7

which antibiotics decreases risk for c.diff?

Answer 7

doxycycline and tigecycline shown to have protective function and active through toxin production inhibition

also has minimal effects on gut flora

Question 8

c.diff infection control and protection measures? (non phx)

Answer 8

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

Question 9

(drug) c.diff infection control and protection measures? (unknown efficacy)

Answer 9

acid suppression
- discontinue uncessary PPIs

probitics
- not routinely recommended

Question 10

cardinal clinical presentation of c.diff?

Answer 10

watery stools ≥3loose stools in 24h

Question 11

(for mild) clinical presentation of c.diff?

Answer 11

diarrhoea, abdominal cramp

Question 12

(for moderate) clinical presentation of c.diff?

Answer 12

fever diarrhoea nausea malaise
abdo cramp and distension
leukocytosis
hypovolemia

Question 13

(for severe) clinical presentation of c.diff?

Answer 13

fever diarrhoea
diffused abdo cramp and distension
wbc≥15x10^9 or scr ≥133umol/L (1.5mg/dL)

Question 14

(for fulminant) clinical presentation of c.diff?

Answer 14

hypotension, shock
ileus
megacolon

Question 15

diagnosis criteria for c.diff?

Answer 15

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

Question 16

stool test requirements for c.diff?

Answer 16

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

Question 17

treatment principles for c.diff?

Answer 17

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

Question 18

treatment for initial episode of c.diff? (first-line) (nonsevere)

Answer 18

po vancomycin 125mg QD x10 days (14 if unresolved)

Question 19

treatment for initial episode of c.diff? (alternative) (nonsevere)

Answer 19

PO metronidazole 400mg TDS x10 days (14 if unresolved)

Question 20

definition of non-severe c diff?

Answer 20

WBC <15x10^9/L
SC<133umol/L (1.5mg/dL)

Question 21

treatment for initial episode of c.diff? (first-line) (severe)

Answer 21

po vancomycin 125mg QDx10 days (14 if unresolved)

Question 22

definition of severe c diff?

Answer 22

WBC ≥15x10^9/L
SC≥133umol/L (1.5g/dL)

Question 23

treatment for initial episode of c.diff? (first-line) (fulminant)

Answer 23

IV metronidazole 500mg Q8
+
PO vancomycin 500mg QD
+/-
PR vancomycin 500mg QD

x10 days (14 if unresolved)

Question 24

definition of fulminant c diff?

Answer 24

hypotension
or
ileus
or
megacolon

Question 25

definition of recurrent c.diff?

Answer 25

resolution -> sudden reappearance

around 30% have recurrence

Question 26

risk factors for recurrent c.diff?

Answer 26

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

Question 27

first treatment for recurrent c.diff?

Answer 27

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

Question 28

c diff monitoring?

Answer 28

resolve in 10 days, otherwise extend for another 4 days of tx

additional diagnostics or consider escalation if poor response

Question 29

special properties of metronidazole in CDI?

Answer 29

IV metronidazole able to undergo enterohepatic circulation back to the gut, thereby affecting colonic flora

generally most iv wont re-enter the gut.