C. difficile Associated Diarrhoea

Question 1

Describe the c. difficile bacteria.

Answer 1

gram positive spore-forming anaerobic bacillus with toxigenic (produce toxins A and B) and non-toxigenic strains

Question 2

What are the risk factors for C. diff infection?

Answer 2

• age > 65yo
• multiple / severe comorbidities
• immunosuppression
• history of CDI
• GI surgery
• tube feeding
• duration of hospitalisation
• nursing home / long-term care facility
• use of gastric acid suppressant therapy
• use of abx

Question 3

Which antibiotics are highly associated with CDI?

Answer 3

clindamycin, 3rd and 4th gen cephalosporins, fluoroquinolones

Question 4

Which antibiotics may have a protective effect against CDI?

Answer 4

doxycycline / tigecycline
- active against c. diff growth and inhibits toxin production
- minimal effects on gut flora

Question 5

What is necessary for the diagnosis of CDI?

Answer 5

1. presence of diarrhoea / radiographic evidence of ileus / toxic megacolon
2. positive stool test for c. diff or its toxins / colonoscopic or histopathologic evidence of pseudomembranous colitis

Question 6

What are the important points for c. diff stool test?

Answer 6

1. do not perform stool test on asymptomatic patients
2. ensure that pt has not had laxatives in past 48H
3. do not repeat test within 7 days
4. do not repeat test to document cure (pt may still test positive)

Question 7

What is the definition of diarrhoea?

Answer 7

> = 3 loose stools in 24H

Question 8

How to differentiate between non-severe and severe CDI?

Answer 8

If WBC >= 15 or SCr >= 133, is severe

Question 9

What are the symptoms of a patient presenting with fulminant CDI?

Answer 9

shock / hypotension, ileus, megacolon

Question 10

What is the recommended regimen for the treatment of non-severe CDI?

Answer 10

First-line: PO vancomycin 125mg QDS
Alt: PO metronidazole 400mg TDS

Question 11

What is the recommended regimen for the treatment of severe CDI?

Answer 11

PO vancomycin 125mg QDS

Question 12

What is the recommended regimen for the treatment of fulminant CDI?

Answer 12

IV metronidazole 500mg Q8H + PO vancomycin 500mg QDS +- PR vancomycin 500mg QDS

Question 13

What is the treatment duration for CDI?

Answer 13

10 days, extend to 14 if necessary

Question 14

What is the definition of recurrent CDI?

Answer 14

initial resolution of symptoms and reappearance after treatment discontinuation

Question 15

What are the risk factors for recurrent CDI?

Answer 15

• use of other abx concurrently
• defective humoral response towards toxins
• use of PPI
• severe underlying disease

Question 16

What is the recommended regimen for the treatment of recurrent CDI, if metronidazole was used for the initial treatment?

Answer 16

PO vancomycin 125mg QDS x 10d

Question 17

What is the recommended regimen for the treatment of recurrent CDI, if vancomycin was used for the initial treatment?

Answer 17

PO fidaxomicin 200mg x 10d
PO fidaxomicin 200mg x 5d, then EOD x 20d
PO vancomycin tapered / pulsed