ID - Viva - Fungal Infections Flashcards
(29 cards)
Why are fungal infections more prevalent in critical illness
More immnocomprimised pts in ICU - chemo, HIV, transplant
Increasing use of invasive devices
Broad spec Abx usage
Increasing aggressvie medical/surgical intervention
What is an Invasive Fungal Infection
The presence of a fungaemia (in blood)
OR
Deep seated infection due to haematogenous spread
It distinguises systemic infection from colonisation of a non-sterile site with no evidence of infection, and sperficial (dermatitis, oesophagitis)
Name some important fungal pathogens in critical illnes
Candida albican accounts for 50% of fungal infections
Candida itself is the 6 to 10th commonest pathogen in European ICU
Rest are non-albican candida species and incidence is increasing, due to increased use of fluconazole
Aspergillus rises to 15%
Risk factors for fungal infection
Patient factors
Abdominal surgery, hollow perf viscous
Co-morbid - COPD, DM, liver failure
Immunosuppression
Colonisation of multiple sites
ITU factors
Being in ITU - high rate of colonisation and transmission
High APACHE II score
AKI on RRT
TPN
Presence of catheters, wonds, burns ETT
Criteria for fungal infection
Definitive criteria:
1) single positive blood culture (NEVER MISTAKE FOR A CONTAMINANT)
2) Positive culture from biopsy
3) Endopthalmitis
4) Burn wound invasion
5) positive ascitic fluid or CSF culture
Invasive - present of 3 colonised sites
What suspicious features lead to disseminated fungal infection
Immunocomp patiets - may show no features
Non specific inflam response and evidence of organ dysfunction.
Treat if there is:
Persistant fever despite Abx and negative micro
High grade funguria in UNCATHETERISED PATIENT
Fungiuria persisting AFTER catheter removal
Fungus culture from >2 sites
Confirmed visceral fungal lesions
How to investigate
Blood cultures - though only positive in 50% Examine retinas for endopthalmititis Urine for culture Echo if endocarditis suspected Tissue biopsies
How to manage suspected fungal infection
ABCDE and treat abnormalities
Start antifungals immediately
Do not wait for micro confirmation
If theres a candida isolate?
If candida isolate: often from resp secretions (true LRTI is rare)
Isolated growth from resp specimans should not prompt therapy in most patents
If asymptomatic candiduria
Change catheter
Treat IF candiurai persistss OR high risk patient
What are the management steps for proven candidaemia?
Change line, send tip for MC&S
Early line removal –> better outcomes in non-immunocompromised
C.parapsilsos forms biofilms so if isolated - do not re-wire
Prognosis of candidaemia
Mortality 40-63%
Early tx - better prognosis
What is Aspergillus
Spore forming moulds found in soil
Only a few species are harmful
Aspergillus fumigatus, followed by aspergillus niger
Commonest site of infection for aspergillus
lung
What is an aspergilloma
a fungal ball,
How does asperigillus pneumonia present
Fever, cough, dypnoea, pleuritic pain, haemoptysis
PCR to detect fungal DNA
Galactomannan is present in the cell wall of aspergillus from blood and BAL
Classifications of antifungals
Polyenes
Azoles
Echinocandins
Example of polyene
Amphotericin B
Example of Azole
Fluconazole
Itraconazole
Voriconazole
Example of Echinocandins
Caspofungin
How does amportercin work
Fungicide polyene
Binds ergosterol in fungal cell wall –> death
Dose limiting nephrotoxic
Broad spec
Fever chills and rigours common
How does fluconazole work
Fungistatic azole (inhibits ergosterol synthesis)
Active against candida but NOT aspergillus
Some non-albicans species are resistant
100% bioavailabiltiy
Prolongs QT
How does caspofungin work
Echinocandin
Inhibit cell wall glucan synthesis - fungicidal for candida, fungistatic for aspergilllus
IV only
Good side effect profile
Synergistic with polyenes (amph B)
What is voriconazole active for
All candida species
First lone for invasive aspergillus
