IC17 C Diff infection Flashcards
What feature of C Diff bacteria allows it to stay in our environment for very long even despite disinfection?
C diff forms spores
What does C Diff bacteria produce?
toxins A & B
What is the route of transmission of C Diff?
fecal oral
What are the risk factors for CDI?
- use of abx
- acid suppression therapy
- history of CDI
- GI surgery
- tube feeding
- residence in nursing homes & long term care facilities
- old age >65
- immunosuppression
- multiple/severe comorbidities
- prior hospitalization in the past 1 year
- prolonged hospitalization
What antibiotics are associated with higher CDI risk?
- clindamycin
- cephalosporins (3rd & 4th gen)
- fluoroquinolones
- amox-clav (BLI component)
What antibiotics have protective effects against CDI?
Doxycycline/tigecycline
Why do they have protective effects against CDI?
- active against C Diff
- inhibit toxin production
- minimal effects on gut microbiome
What are the steps for infection control for CDI?
- isolation
- practice hand and personal hygiene (wear PPE [gloves & gown], handwash with soap & water > alcohol handrub)
- environmental sanitation w sporicidal agents
- antimicrobial stewardship
What is the ONE symptom that CDI always present with?
watery diarrhoea (≥3 loose stools in 24h)
What are the risk classifications of CDI?
- mild
- moderate
- severe
- fulminant
What are the symptoms of mild CDI?
- Diarrhoea
- Abdominal cramps
(No systemic signs of infection)
What are the symptoms of moderate CDI?
- Diarrhoea
- Abdominal cramps & distension
- Fever
- Nausea
- Malaise
- Leukocytosis (elevated WBC)
- Hypovolemia
What are the symptoms of severe CDI?
- Diarrhoea
- Diffused abdominal cramps & distention
- Fever
- WBC ≥15 or SCr ≥133
What are the symptoms of fulminant CDI?
- Hypovolemia/shock
- Ileus (no more peristalsis)
- Megacolon (become v large)
What are the diagnostic criteria for CDI?
A + B
A
- diarrhoea (≥3 loose stools in 24h)
- radiographic evidence of toxic megacolon/ileus
B
- positive stool test for C Diff/toxins
- colonoscopic/histopathologic evidence of pseudomembranous colitis
When do we perform stool test?
ONLY for symptomatic patients (ie. have diarrhoea)
What do we need to look out for when performing stool test?
prior laxative use 48h before test
What is the minimum duration before we can repeat stool test?
7 days
Do we repeat stool test to determine if the patient is cured of CDI?
NO
What are the antibiotics available for use for the first episode of CDI?
- Vanco
- Fidaxomicin
- Metronidazole
What is the definition of non-severe (ie. mild to moderate) CDI?
- diarrhoea
- positive stool test
- WBC <15 AND SCr <133 umol/L
What antibiotics (& what formulation) can we use for non-severe CDI?
first line:
PO vanco
PO fidaxomicin
alternative:
PO metronidazole
What is the definition of severe CDI?
- diarrhoea
- positive stool test
- WBC ≥15 OR SCr ≥133 umol/L
What antibiotics (& what formulation) can we use for severe CDI?
PO vanco
PO fidaxomicin
What is the definition of fulminant CDI?
- diarrhoea
- positive stool test
- hypovolemia OR ileus OR megacolon
What antibiotics (& what formulation) can we use for fulminant CDI?
IV metronidazole + PO/PR vanco
What is the dose of oral fidaxomicin used for initial episode of non-severe AND severe CDI?
200mg BD
What is the dose of oral vanco used for initial episode of non-severe and severe CDI?
125mg QDS
What is the dose of PO & PR vanco used for initial episode of fulminant CDI?
500mg QDS
(same dose for PO & PR)
Wha is the dose of PO metronidazole used for initial episode of non-severe CDI?
400mg TDS
What is the dose of IV metronidazole used for initial episode of fulminant CDI?
500mg Q8h
(technically is also TDS)
What is the duration of treatment for the initial episode of CDI?
10 days
14 days if symptoms have not completely resolved
What is the definition of recurrent CDI?
symptoms of CDI resolved, and subsequently reappeared after treatment has been discontinued
What are the risk factors for CDI recurrence?
- administration of abx during/after initial treatment
- continued use of PPIs
- defective humoral immune response against C Diff (cannot produce Abs against toxin)
- old
- severe underlying disease
What do we use for the FIRST recurrence of CDI if vanco/fidaxomicin was used for the first episode?
still use vanco/fidaxomicin
What is the dosing regimen of vanco for the first recurrence of CDI assuming vanco was used for the first episode?
tapered/pulsed
What is the dose & dosing regimen of fidaxomicin for the first recurrence of CDI assuming vanco/fidaxomicin was used for the first episode?
- PO 200mg BD x 10 days
- PO 200mg BD x 5 days –> 200mg EOD x 20 days
(same dose of 200mg as for first ep)
What do we use for the FIRST recurrence of CDI if metronidazole was used for the first episode?
vanco
What is the dose & dosing regimen of vanco for the first recurrence of CDI assuming metronidazole was used for first episode?
125mg QDS x 10 days
(same dose as for non-severe and severe CDI)
How long does it take for CDI symptoms to resolve?
10 days
What if symptoms have not resolved by that duration?
extend treatment by another 4 days
