Fungal Infections Flashcards
Give 3 examples of fungal pathogens.
Aspergillus species -Aspergillus fumigatus
Candida species
-Candida albicans
Cryptococcus species
-Cryptococcus neoformans
Why type of nature do fungal pathogens have?
Opportunistic nature
Why are fungal pathogens said to be opportunistic?
- Affect patients with impaired immune system
- Affect patients with chronic lung disease
- Affect patients in ICU settings
Give an example of a condition associated with the pneumocystic species.
Pneumocystis pneumonia
Give an example of a condition associated with the aspergillus species.
Allergic and invasive pulmonary aspergillosis
Give examples of conditions associated with the candida species.
- Thrush
- Candidemia
Give an example of a condition associated with the Cryptococcus species.
Meningitis
What are the prime conditions for mucocutaneous candidiasis to occur?
- Antibiotic use
- Moist areas
- Inhalation steroids
- Neonates < 3 months
What is mucocutaneous candidiasis the presenting symptom of?
Primary immunodeficiency disorders
How are primary immunodeficiency disorders characterised?
- Neutropenia
- Low CD4 T cells
- Impaired IL17 immunity
Give examples of impaired IL17 immunity
AD-Hyper IgE syndrome
-Deficit of IL-17 producing cells
Dectin-1 deficiency
-Reduced levels of IL-17
CARD9 deficiency
-Low proportion of circulating IL-17 T-cells
APECED syndrome
-High titers of neutralizing Ab against IL-17A, IL-17F and/or IL-22
What is the origin of invasive candidiasis?
- Gut commensal
- Infections mostly endogenous of origin
- 4th most common bloodstream infection (BSI) in adults: 30/100.000 admissions
What are the risk factors for invasive candidiasis?
- Broad spectrum antibiotics
- Intravascular catheters
- Total parenteral nutrition
- Abdominal surgery
- Premature neonates
How is invasive candidiasis diagnosed?
- Blood culture or culture from normally sterile site
- β-d-glucan high NPV and performs very well to exclude invasive candidiasis
- Recent developments in PCR assays very promising
- In infants and children performance lower due to sampling issues
How is aspergillus transmitted?
- Sporulation
- Hydrophobic conidia
- Diameter 2-3um
- Airborne/inhalation
What plays a central role in invasive pulmonary aspergillosis?
Neutrophils
How can aspergillus disease be classified?
- Acutee aspergillosis
- Chronic pulmonary aspergillosis (3 months)
- Allergic aspergiloosis
Who is usually affected by acute invasive pulmonary aspergillosis?
- Neutropenic patients (incidence 1-10%)
- Post transplants: stem cell > solid organ (incidence up to 8%)
- Patients with defects in phagocytes
Who is usually affected by chronic pulmonary aspergillosis?
Patients with underlying lung conditions
Who is usually affected by allergic aspergillosis?
- Allergic bronchopulmonary aspergillosis in CF and asthma (incidence 10-15%)
- Asthma or CF with fungal sensitisation (incidence 5-15%)
How does acute invasive pulmonary aspergillosis present?
-Rapid and extensive hyphal growth
-Thrombosis and hemorrhage
-Angio-invasive and dissemination-
Absent or non-specific clinical signs and symptom
-Persistent febrile neutropenia despite broad-spectrum antibiotics
-Mortality rates around 50% (but depending on immune recovery)
Who is the host in acute invasive pulmonary aspergillosis?
Neutropenic host (acute leukaemia, haematopoietic stem cell transplant)
Who is the host in (Sub( acute invasive pulmonary aspergillosis?
Non-neutropenia host (graft versus host disease, neutrophil disorders)
How does sub-acute invasive pulmonary aspergillosis present?
- Non-angioinvasive
- Limited fungal growth
- Pyogranulomatous infiltrates
- Tissue necrosis
- Excessive inflammation
- Non-specific clinical signs and symptoms
- Mild to moderate systemic illness
- Mortality 20-50%
