Fungal Infections Flashcards
Fungal pathogens are said to be opportunistic in who they infect. What makes a patient more susceptible to infection?
> Impaired immune system (immunodeficiencies, HIV/AIDS, malignancies and transplants, neonates)
Chronic lung diseases (asthma, CF, COPD)
ICU patients
What makes you more likely to be infected by mucocutaneous candidiasis?
- Antibiotic use
- Moist areas
- Inhalation steroids
- Neonates <3m
Mucocutaneous candidiasis is a presenting symptom of primary immunodeficiency disorders, characterised by what?
>Neutropenia
>Low CD4+ T cells
>Impaired IL-17 immunity
- AD-Hyper IgE syndrome
- Dectin-1 deficiency
- CARD9 deficiencyInvasive candidiasis comes from gut commensal and is mostly endogenous of origin. How does it present and what are risk factors?
Presents as bacterial bloodstream infection.
Risk factors
- Neonates
- Broad spectrum antibiotics
- IV catheters
- Total parenteral nutrition
- Abd. surgery
How do you diagnose invasive candidiasis?
> Blood culture
Culture normally sterile site
Beta-d-glucan high NPV can exclude it
PCR assays developing as investigation
How is Aspergillosis transmitted?
Inhaled. Is airborne spores. Typically affects lungs.
What are the different classifications of pulmonary aspergillosis disease?
- Acute invasive pulmonary aspergillosis
- Chronic pulmonary aspergillosis (>3m)
- Allergic aspergillosis
Acute invasive pulmonary aspergillosis affects neutropenic hosts (acute leukaemia/haematopoietic stem cell transplant). What are the features?
>Thrombosis and haemorrhage >Angio-invasive and dissemination >Absent/non-specific clinical signs and victims >Persistent febrile neutropenia >Mortality rates 50%
Subacute invasive pulmonary aspergillosis affects non-neutropenic hosts (graft vs host disease, neutrophil disorders). What are the features?
>Non-angioinvasive >Pyogranulatomous infiltrates >Tissue necrosis >Excessive inflammation >Non specific clinical signs and symptoms (mild to moderate systemic illness) >Mortality 20-50%
What primary immunodeficiencies can lead to invasive aspergillosis presenting as a symptom?
> Congenital neutropenia
Chronic granulatomous disease
Hyper IgE syndrome
CARD-9 deficiency
Presentation often outside lungs eg bones, spine, brain, abdominal
Chronic pulmonary aspergillosis affects hosts with asthma, CF, and chronic obstructive lung disorders. How do they present?
> Pulmonary exacerbations with lung function decline
Inc respiratory symptoms as couch, dec. exercise tolerance and SOB
Positive sputum culture
High morbidity
Allergic bronchopulmonary aspergillosis results from immunological responses to A. fumigatus antigens in 10-15% CF hosts. What are the features of this?
>Lung function deterioration, respiratory symptoms >Abnormal chest imaging >Inc. immunoglobulin E level >Positive Aspergillus skin test >Positive Aspergillus specific IgG/IgE
Pulmonary aspergilloma is a fungal mass that usually grows in lung cavities. When do these grow?
- TB
- Sarcoidosis
- Bronchiectasis
- Bronchial cysts and bullae
- After pul. infections
What groups of people are emerging as non-nutropenic osts of Aspergillosis?
- Resp insufficiency
- Influenza A virus
In non-neutropenic patients how do you diagnose Aspergillosis?
> Culture sputum/bronchoalveolar lavage/biopsy
>Aspergillus specific IgG/IgE
In neutropenic patients how do you diagnose Aspergillosis?
> CT chest (halo sign)
Molecular markers in blood (galactomannan and PCR-Aspergillus)
BAL and biopsy if possible
How is Cryptococcus transmitted?
Inhalation. Can be found on bark of trees, in bird faeces
What does Cryptococcus cause upon dissemination to brain?
Meningoencephalitis in HIV/AIDS patients
What is the clinical presentation of Cryptococcosis?
- Headache
- Confusion
- Altered behaviour
- Visual disturbances
- Coma (raised ICP)
How do you diagnose cryptococcal disease?
- India ink stain of CSF. CSF culture, high protein and low glucose
- Blood culture, look for cryptococcus antigen
What factors are associated with mortality in cryptococcal meningitis?
- Delay in presentation/diagnosis
- Lack of access to antifungals
- Inadequate induction therapy
- Delays in starting ART
- Immune reconstitution syndrome
What are antifungal agents for invasive fungal infections?
- Amphotericin B formulations (IV)
- Azoles (IV, oral)
- Echinocandins (IV
- Flucytosine (IV, oral)
What is Amphotericin B used for?
Broad spectrum antifungal
What is Echinocandins and fluconazole used for?
Invasive candidiasis
