Infection Flashcards
Why are fungal infections increasing on the ICU?
Increasing numbers of immunocompromised patients
Increased use of invasive devices
Broad-spectrum antibiotic use
Increasingly aggressive medical and surgical interventions.
What does invasive fungal infection mean?
Fungus is present in the blood or is a deep-seated infection as a result of haeatogenous spread.
Which fungal pathogens are important in ICU patients?
Candida albicans accounts for 50% of cases of fungal infection
Non-albicans candida accounts for the majority of the remainder
Aspergillus is increasing and represents up to 15% of all cases
Who is at risk of fungal infection?
ICU admission High APACHE II score Co-morbidities esp COPD, bronchiectasis, liver failure and DM AKI requiring RRT Immunosuppressed Broad-spec antibiotic use Parenteral nutrition Vascular access, wounds, burns, ETT General surgery Candida colonisation of multiple sites
What are the criteria used to diagnose fungal infection?
Definitive - positive blood culture -positive biopsy specimen -endophthalmitis -burn wound invasion positive ascitic tap or CSF
Suggestive if these are 3 colonised sites
How would you manage candida isolated from resp secretions?
true infection of lower resp tract is rare
isolated growth shouldn’t prompt antifungals in most patients
How do you manage asymptomatic candiduria?
Change the catheter
Treat is candiduria persists or in high risk patients
How do you manage candidaemia?
Change lines
In non-neutropenic patients there is evidence foor improfed outcomes with early line removal
C.parapsilosis forms a biofilm so lines growing this should definitely be removed.
What is the prognosis of candidaemia?
40-63% overall mortality
What is Aspergillosis?
They are spore forming moulds found in the soil
Only a few are potentially pathogenic in humans
- Aspergillus fumigatus is the most common followed by niger.
The lung is the most common site
Aspergillus pnuemonia presents with non-specific symptoms such as cough, dyspnoea and pleuritic pain.
PCR can detect fungal DNA and galactomannan (present in the cell wall of Aspergillus) can be detected in blood and BAL samples
What are the 3 classes of antifungals?
Polyenes e.g. Amphotericin B
Azoles e.g. fluconazole
Echonicandins e.g. caspofungin
Describe the properties on polyenes
Antifungal e.g. Amphotericin B Fungicidal, broad-spec Typically cause fevers and chills - premed with antihistamines Cause nephrotoxicity
Describe the azoles
Antifungals
e.g. fluconazole
Active against Candida but not Aspergillus
100% oral bioavailability
CYP450 inhibition
Prolonged QT interval
Itraconazole - increased spectrum of activity
voriconazole - first line treatment for Aspergillosis, active against all candida
Describe the Echinocandins
e.g. caspofungin
Inhibit call wall glucan synthesis
Fungicidal against candida, fungistatic against aspergillus
Synergistic with polyenes
IV only
Good side effect profile with few interactions
Which antifungal would you use to treat candidiasis?
Fluconazole
or amphotericin B/caspofungin (non-ablicans candida may be resistant to fluconazole)
