Infectious Diarrhea Flashcards
Definition of acute infectious diarrhea
Acute : less than 14 days
Infectious : more than 1 pathogens
Diarrhea : >=3 loose stools or more frequent than normal
When to do diagnostic tests for diarrhea
- Bloody stools
- Persisting fever
- Immunosuppressed
- Severe illness
- Non-responsive to treatment
Vaccinations available for infectious diarrhea
- Cholera and typhoid (for those travelling to endemic areas)
- Rotavirus (for infants 6months-5 years)
Indications for antibiotics in infectious diarrhea
- Severe illness (fever w bloody stools, mucoid stools & severe abdominal cramps/distension)
- Sepsis
- Immunocompromised
Empiric treatment for infectious diarrhea
- IV Ceftriaxone 2g q24h
- PO Ciprofloxacin 500mg BD
duration 3-5 days
Clostridioides difficile description
- Gram +ve
- Spore forming
- Anaerobic bacilli
- Toxin A & B
aka Clostridium difficile
C. diff risk factors (healthcare)
- Hospitalisation
- Duration of hospitalisation
- Residence of long term care facilities or nursing homes
C. diff risk factors (pharmacotherapy)
- Systemic use of antibiotics
- Use of high risk antibiotics
- clindamycin
- fluoroquinolones
- 2nd gen and above cephalosporins - Use of gastric acid suppression (PPI)
C. diff risk factors (patient)
- Several or severe comorbidities
- Immunocompromised
- History of CDI
- > 65y/o
Is C. diff treated empirically?
No unless
- Delay in diagnostic >48h
- Fulminant CDI (toxic megacolon, ileus & hypotension)
C. diff diagnosis
- Clinical suspicion
- unexplained new and onset diarrhea
- radiologic evidence of toxic megacolon or ileus - Confirmatory test or findings
- toxin A & B
- glutamate dehydrogenase enzyme
- C.diff PCR
- histopathological findings of pseudomembranous colitis
Initial treatment for CDI (non-severe)
1st line :
- PO Vancomycin 125mg QDS
- PO Fidaxomicin 200mg BD
Alternative if failed above :
- PO Metronidazole 400mg TDS
duration 10 days. 14 days if symptoms still present
Non-severe CDI definition
- WBC < 15x10^9/L
AND - SCr < 133umol/L
Initial treatment for CDI (severe)
- PO Vancomyin 125mg QDS
- PO Fidaxomicin 200mg BD
duration 10 days. 14 days if symptoms still present
Severe CDI definition
- WBC >= 15x10^9/L
- SCr >= 133umol/L
any one
Initial treatment for CDI (fulminant)
IV Metronidazole 500mg q8h \+ PO Vancomycin 500mg QDS \+- PR Vancomycin 500mg QDS
duration 10 days. 14 days if symptoms still present
Fulminant CDI definition
- Toxic megacolon
- Ileus
- Hypotension
any one
First recurrence of CDI treatment
aka 2nd episode
If use metronidazole in 1st episode :
- PO Vancomycin 125mg QDS x 10 days
- PO Fidaxomicin 200mg BD x 10 days
If use 1st life in 1st episode :
- PO Fidaxomicin 200mg BD x 10 days
- PO Vancomyin taper
Second recurrence and above of CDI
aka 3rd episodes and above
- PO Fidaxomicin 200mg BD x 10 days
- PO Vancomycin taper
- PO Vancomycin 125mg QDS x 10 days followed by PO Rifaximin 300mg TDS x 20 days
- Fecal microbiota transplant
How is PO Vancomycin compounded?
From IV Vancomycin solutions
Why is metronidazole not used again after it is used once?
To prevent cumulative and potentially irreversible neurotoxicity
Benefits of Fidaxomicin
- lower MIC than for metronidazole and vancomyin
- post antibiotic effect 5.5h-12.5h
- less effect on normal gut flora (narrow spectrum)
Limitation of Fidaxomicin
Very expensive, hence limit use for severe and/or recurrent cases non-responsive to maximal treatment
Expected clinical improvement in _______
5-7 days
