Fungal Infection Flashcards
which patients are at higher risk of fungal infections?
> patients in ICU
impaired immune system (malignancies, HIV, premature neonates, transplants)
chronic lung disease (cystic fibrosis, asthma, COPD)
what are some risks for mucocutaneous candidiasis?
> antibiotic use
moist areas
inhalation steroids
neonates <3months
how may mucocutaneous candidiasis present?
> neutropenia
low CD4 ++ cells
impaired IL-17 immunity
what are some risk factors for invasive candidiasis?
> IV catheters
broad spectrum antibiotics
abdominal surgery
total parental nutrition
how does invasive candidiasis present?
bacterial blood stream infection
how is invasive candidiasis diagnosed?
> culture from a normally sterile site
> b-ol-glucan excludes invasive candidiasis
how is invasive candidiasis treated?
echinocandins and fluconazole
how is cryptococcosis meningitis spread?
via inhalation from bird faeces and tree bark
what is the pathophysiology of cryptococcosis meningitis?
a pulmonary infection that then disseminates to the brain
how does cryptococcosis meningitis present?
> confusion > headache > altered behaviour > visual disturbance > coma
hoe is cryptococcosis meningitis diagnosed?
> CSF culture
> blood culture
what factor in a cryptococcosis meningitis infection are associated with mortality?
> lack of antifungal access > delay in presentation > inadequate induction therapy > delays in starting antiretroviral therapy (HIV) > immune reconstitution syndrome
how is a cryptococcosis meningitis infection treated?
flucytosine followed by fluconazole maintenance
how is aspergillus aspergillosis transmitted?
> sporulation
> airborne
describe the pathophysiology of aspergillus aspergillosis
there is conidial germination in absence of sufficient pulmonary defences leading to neutropenia and excessive hyphal growth and dissemination
what are the risk factors for acute invasive pulmonary aspergillosis?
a neutropenic host (acute leukaemia or hemopoietic stem cell transplant)
how does acute invasive pulmonary aspergillosis present?
> absent or non-specific symptoms
> persistent febrile neutropenia despite broad spectrum antibiotics
describe the pathophysiology of acute invasive pulmonary aspergillosis
> angioivasive and dissemination
thrombosis and haemorrhage
rapid and extensive hyphal growth
how is acute invasive pulmonary aspergillosis treated?
voriconazole and isaruconazole
what are the risk factors for subacute invasive pulmonary aspergillosis?
a non-neutropenic host (neutrophil disorder)
describe the pathophysiology of subacute invasive pulmonary aspergillosis?
> excessive inflammation
pyogranulomatous infiltrates
tissue necrosis
what are the risk factors for chronic pulmonary aspergillosis?
> asthma
cystic fibrosis
COPD
what is the presentation of chronic pulmonary aspergillosis?
> pulmonary exacerbation not responding to antibiotics > lung function decline > increased resp. symptoms > decreased exercise tolerance > high morbidity
what investigation would you carry out for suspected chronic pulmonary aspergillosis?
sputum culture
how does allergic bronchopulmonary aspergillosis present?
> deterioration of lung function and resp. symptoms
increased IgE
positive aspergillosis specific IgG
new abnormalities of chest imaging
what is a pulmonary aspergilloma?
a fungal mass grown in lungs
what risk factors are there for a pulmonary aspergilloma?
> TB
sarcoidosis
bronchial cysts and bullae
bronchiectasis
how would you diagnose aspergillus aspergillosis in a non-neutropenic patient?
> aspergillus specific IgG and IgE
bronchoalveolar lavage
cultures of sputum
biopsy
how would you diagnose aspergillus aspergillosis in a neutropenic patient?
> high resolution chest x-ray (halo sign)
bronchioalveolar biopsy if conditions allow
molecular markers in the blood: galactomannan, PCR aspergillus
what can be used for antifungal prophylaxis?
> itraconazole
> posaconazole
what does flucytosine inhibit?
fungal DNA synthesis
what does echinocandins inhibit?
glucan synthesis
what do azoles inhibit?
ergosterol synthesis
what do amphotericin B formulations act on?
ergosterol (more than lysis)???
