C Diff

Question 1

Characteristics of C Diff?

Answer 1

Gram +ve, anaerobic, spore-forming bacillus

Question 2

What toxins do toxigenic strains of C Diff produce? Are there non-toxigenic strains?

Answer 2

Toxin A and B
Yes

Question 3

How is C Diff transmitted?

Answer 3

Spores transmitted via fecal-oral route

Question 4

What is the pathogenesis of C Diff?

Answer 4

abx use -> disrupt barrier function of normal colonic flora -> C diff enter via fecal-oral route -> multiply & produce toxin A & B -> inflammation & diarrhoea -> pseudomembranous colitis (yellowish plaques form over damaged epithelium)

Question 5

Which abx have higher risk of C Diff?

Answer 5

• clindamycin (highest risk)
• 3rd & 4th gen cephalorsporins
• FQ
• ampicillin, amoxicillin

Question 6

Which abx may be protective against C Diff? Why?

Answer 6

Doxycycline, tigecycline
Active against C Diff growth & inhibits toxin production, min effects on gut flora

Question 7

C Diff infection control and prevention measures?

Answer 7

• isolation (private room with dedicated toilet)
• hand hygiene (gown, gloves, hand washing instead of alcohol hand rub)
• env cleaning with sporicidal agents
• antimicrobial stewardship

Question 8

How much watery diarrhoea can be considered as C Diff?

Answer 8

≥3 loose stools in 24h

Question 9

Symptoms of mild, moderate, severe and fulminant C Diff?

Answer 9

Mild: diarrhoea, abd cramps
Moderate: diarrhoea, fever, nausea, malaise, abd cramps & distension, leukocytosis, hypovolemia
Severe: diarrhoea, fever, diffused abd cramps & distension, WBC ≥ 15x10^9/L or SCr ≥ 133 µmol/L
Fulminant: hypotension/shock, ileus, megacolon

Question 10

What is needed for diagnosis of C Diff?

Answer 10

Both:
- presence of diarrhoea (≥3 loose stools in 24h) OR radiographic evidence of ileus/toxic megacolon
- +ve stool test result for C Diff or its toxins OR colonoscopies/histopathologic evidence of pseudomembranous colitis

Question 11

Should you test asymptomatic patients?

Answer 11

No

Question 12

Before testing, what should patients make sure they did not receive and for how long?

Answer 12

Laxative within prior 48h

Question 13

What is considered as initial non-severe C Diff and what is the treatment?

Answer 13

Non-severe: WBC < 15 x 10^9 /L AND SCr < 133 µmol/L

1st line: PO vancomycin 125mg QDS or PO fidaxomicin 200mg BD

Alternative: PO metronidazole 400mg TDS

Question 14

What is considered as initial severe C Diff and what is the treatment?

Answer 14

Severe: WBC ≥ 15 x 10^9 /L OR SCr ≥ 133 µmol/L

1st line: PO vancomycin 125mg QDS or PO fidaxomicin 200mg BD

Question 15

What is considered as initial fulminant C Diff and what is the treatment?

Answer 15

Fulminant: hypotension OR ileus OR megacolon

1st line: IV metronidazole 500mg Q8h + PO vancomycin 500mg QDS +- PR vancomycin 500mg QDS

Question 16

Duration of treatment of C Diff of any severity?

Answer 16

10 days (up to 14 days if sx not completely resolved)

Question 17

Which abx used for C Diff has a lower recurrence rate?

Answer 17

Fidaxomicin

Question 18

What is recurrent C Diff?

Answer 18

Resolution of C Diff sx, followed by subsequent reappearance of sx after tx has been discontinued

Question 19

Treatment for first C Diff recurrence?

Answer 19

If used fidaxomicin/vancomycin for initial episode:
- PO fidaxomicin 200mg BD x 10D
- PO fidaxomicin 200mg BD x 5D then 5mg EOD x 20D
- PO vancomycin tapered/pulsed: 125mg QDS x 10-14D, 125mg BD x7D, 125mg OD x7D, 125mg Q2-3D x 2-8w

If used metronidazole for initial episode:
- PO vancomycin 125mg QDS x 10D

Question 20

Should C Diff treatment be continued after 14 days?

Answer 20

No

Question 21

Should you use PPIs in pts with C Diff? Why?

Answer 21

Cannot, it may trigger recurrence