Fungal Infections Flashcards
What are the main fungal pathogens?
- Aspergillus species
- Aspergillus fumigatus
- Candida species
- Candida albicans
- Cryptococcus species
- Cryptococcus neoformans
What are fungal pathogens in nature?
Fungal pathogens are opportunistic in nature:
- Affects patients with impaired immune systems
- Primary immunodeficiency’s
- Patients with HIV/AIDS
- Patients with malignancies
- Premature neonates
- Patients with transplants
- Affects patients with chronic lung diseases
- Asthma
- Cystic fibrosis
- Chronic obstructive lung disorders
- Patients in ICU
What are some specific fungal diseases?
What is candidiasis?
Infection due to any type of candida (type of yeast)
What kind of fungus is candida?
Yeast
What is mucocutaneous candidiasis also known as?
Thrush
What is thrush caused by?
Candida spp
What is thrush?
An immune disorder of T cells characterised by chronic infections with candida that are limited to mucosal surfaces, skin and nails
What is the presentation of thrush?
- Characterised by neutropenia, low CD4 T cells and impared IL-17 immunity
What is the treatment for thrush?
Inhaled steroids
What is invasive candidiasis?
- Gut commensal (candida), infection mostly endogenous in origin
What are risk factors for invasive candidiasis?
- Broad spectrum antibiotics
- IV catheters
- Total parenteral nutrition
- Abdominal surgery
How is invasive candidiasis diagnosed?
- Blood culture or culture from normal sterile site
How is aspergillus transmitted?
- Sporulation
- Airborne/inhalation
- Diameter 2-3um
What is a common disease caused by aspergillus?
Invasive pulmonary aspergillosis
Describe the pathogenesis of invasive pulmonary aspergillosis?
1) Sporulation
2) Inhalation
3) Germination occurs in absence of pulmonary defences
4) Causes neutropenia due to excessive hyphal growth and dessemination
What are the different classifications of pulmonary aspergillus?
-
Acute invasive pulmonary aspergillosis
- Usually occurs in neutropenic patients, post-transplant and patients with defects in phagocytes
- Neutropenic host:
- Rapid and extensive hyphal growth
- Thrombosis and haemorrhage
- Angio-invasive and dissemination
- Non-specific clinical signs and symptoms
- Non-neutropenic host
- Non-angiovasive
- Limited fungal growth
- Tissue necrosis and excessive inflammation
- Non-specific clinical signs and symptoms
-
Chronic pulmonary aspergillosis (>3 months)
- Occurs in patients with underlying chronic lung conditions
- Pulmonary exacerbations that do not respond to antibiotics
- Lung function decline
- Increased respiratory symptoms such as cough, decreased exercise tolerance and dyspnoea
- Positive sputum culture for aspergillus
-
Allergic aspergillosis
- Allergic bronchopulmonary aspergillosis occurs in CF and asthma patients
- Immunological response to variety of A. Fumigatus antigens causing
- Acute/subacute deterioration of lung function and respiratory symptoms
- Elevated immunoglobulin E (IgE) levels
- Positive aspergillus specific IgG
-
Pulmonary aspergilloma
- Fungal mass that usually grows in lung cavities
- Occurs in patients with
- TB
- Sarcoidosis
- Bronchiectasis
- Bronchial cysts and bullae
- After pulmonary infections