Infectious diarrhea and CDAD Flashcards
Definition of acute
Increased frequency of defecation lasting <14 days
Definition of diarrhea
> =3 loose or liquid stools, OR more frequent than normal for an individual
What are the types of microorganisms that can cause acute infectious diarrhea?
Bacterial, protozoal, viral
What are the diagnostic tests used to diagnose acute infectious diarrhea?
Fecal occult blood, ova and parasite, stool cultures, polymerase chain reaction (PCR)
Why might stool cultures not be commonly done in practice?
Acute infectious diarrhea is self-limiting, and since stool cultures take a few days, patients may already be recovered when the results are back
For which patients are diagnostic tests indicated for?
Immunosuppressed Unresponsive to treatment Bloody stools Persistent fever Severe illness
What vaccinations are recommended for those travelling to countries with poor sanitation status?
Typhoid (Salmonella typhi) and Cholera (Vibrio cholera)
What vaccinations are recommended for infants or children 6 months - 5 years for the prevention of acute infectious diarrhea?
Rotavirus
Non-pharmacologic treatment of acute infectious diarrhea
Early re-feeding as tolerated
Easily digestible food (e.g. crackers, toast, cereal, bananas)
Do all patients require antibiotics? What are the indications for antibiotics?
No, most are self-limiting
Severe disease (fever with bloody diarrhea, OR mucoid stools, OR severe abdominal pain/cramps/tenderness)
Sepsis
Immunocompromised
What is the empiric antibiotic therapy for acute infectious diarrhea?
Ceftriaxone 2g IV q24h
Ciprofloxacin 500mg PO BD
What is the duration of therapy for acute infectious diarrhea? When is it extended?
3-5 days
Extended in patients with bacteremia, extra intestinal infections or immunocompromised patients
Is IV to PO step down therapy needed for acute infectious diarrhea?
No, as antibiotic duration is already very short
What type of bacteria is C difficile?
Gram positive, spore forming anaerobic bacillus producing Toxins (A and B)
How is C difficile transmitted?
Fecal oral route
Contaminated environmental surfaces
Hand carriage by healthcare workers
What is the pathogenesis of C difficile infection?
Alteration to normal gut flora
C difficile spores are passed from patient to patient
Spores enter the intestine, start to replicate and produces toxins
Toxins damages the GI mucosa that causes bleeding and other symptoms of C difficile
What are the types of risk factors for C diff infection?
Healthcare exposure
Pharmacotherapy
Patient-related factors
What are the healthcare exposure related risk factors for C difficile infection?
Prior hospitalisation
Duration of hospitalisation
Residence in nursing home or long-term care facilities
What are the pharmacotherapy related risk factors for C diff infection?
Systemic antibiotics (no of agents, duration of therapy)
High risk antibiotics (clindamycin, fluoroquinolones, 2nd of higher generation cephalosporins)
Use of gastric acid suppressive therapy
What are the patient-related risk factors for C diff infection?
Multiple or severe comorbidities
Immunosuppression
Age > 65 years
history of CDI
What are the symptoms of fulminant/severe CDI?
Ileus, toxic megacolon, pseudomembranous colitis, perforation, death
What is the clinical suspicion for C difficile infection?
New and unexplained onset of diarrhea
Radiologic evidence of ileus or toxic megacolon
What is the confirmatory test for C diff infection?
Positive stool test for C difficile or its toxins
Histopathologic evidence of pseudomembranous colitis
What are the diagnostic tests for C diff infection?
Nucleic acid amplification test (toxin enzyme immunoassay, glutamate dehydrogenase EIA)
PCR
Do we test asymptomatic patients for C diff infection?
No, always starts with clinical suspicion, which is based on symptoms
After diarrhea resolves, how long is contact precautions recommended for (ie gloves and gown wearing)?
48 hours
When is empiric CDI treatment recommended?
Substantial delay (>48 hours) in diagnostics, OR fulminant CDI
What is the definition of a non-severe episode of C difficile infection?
WBC < 15 x 10^9/L AND Scr < 133 umol/L (1.5mg/dL)
What is the definition of a severe episode of C difficile infection?
WBC >= 15x10^9/L OR SCr >= 133umol/L (1.5mg/dL)
What is the definition of fulminant C difficile infection?
toxic megacolon OR ileus OR hypotension OR pseudomembranous colitis
When is vancomycin given as enema?
When there is ileus
What drug is given IV for the treatment of C diff infection and under what circumstances?
Metronidazole
When patient has fulminant C diff infection
What is the recommended treatment for non-severe C diff infection?
First line: vancomycin 125mg PO QDS, Fidaxomycin 200mg PO BD
Alternative: metronidazole 400mg PO TDS
What is the recommended treatment for severe C diff infection?
Vancomycin 125mg PO QDS
Fidaxomicin 200mg PO BD
What is the recommended treatment for fulminant C diff infection?
Metronidazole IV 500mg Q8H
Vancomycin 500mg PO QDS
Vancomycin 500mg PR QDS
Treatment duration for initial episode of C diff infection
10 days
When should metronidazole not be considered?
Patient has repeated or prolonged courses (as potentially irreversible neurotoxicity)
What are the treatment options for first recurrence?
If treated with metronidazole:
Treat with vancomycin 125mg PO QDS x10 days
If treated with first line regimen first episode:
Fidaxomicin 200mg PO BD x 10 days
Vancomycin PO taper
What are the treatment options for second or subsequent recurrence?
Fidaxomicin 200mg PO BD x 10 days
Vancomycin PO taper
Vancomycin 125mg PO QDS x 10 days followed by rifaximin 300mg PO TDS x 20 days
Fecal microbiota transplant
If a patient is receiving 4 weeks pip-tazo for treatment of his DFI and subsequently develops C difficile infection, how long should he stay on Vancomycin?
10 days
Are anti-motility agents recommended for use during C diff infection?
No, it reduces bowel output, affecting ability to perform stool testing. Associated with poor outcomes
