Fungal Infections Flashcards
What are the three main fungal pathogens?
Aspergillus species
Candida species
Cryptococcus species
Who is most likely to be affected by a fungal pathogen?
Immunocompromised
Chronic lung disease
Patient in ICU setting
What are the risk factors for mucocutaneous candidiasis?
Antibiotic use
Inhalation steroid use
Neonates <3 months
Most common in moist areas
What are the presenting symptoms of mucocutaneous candidiasis?
Neutropenia
Low CD4+ T-cells
Impaired IL-17 immunity
What are the features of invasive candidiasis?
Gut commensal and endogenous in origin
Presents clinically as bacterial bloodstream infection
Mortality rate 40%
What are the risk factors for invasive candidiasis?
Broad spectrum antibiotics
Intravascular catheters
Total parenteral nutrition
Abdominal surgery
How is invasive candidiasis diagnosed?
Blood culture or culture from normally sterile site
Β-d-glucan good to exclude invasive candidiasis
Possibility to use PCR assays
Diagnosis more difficult in children due to sampling issues
How is primary aspergillus disease classified?
Acute invasive pulmonary aspergillosis: - Neutropenic patients - Post transplant - Patients with defects in phagocytes Chronic pulmonary aspergillosis: -Infection lasts > 3 months - Patients with underlying chronic lung conditions Allergic aspergillosis: -Allergic bronchopulmonary aspergillosis in CF and asthma - Asthma or CF with fungal sensitisation
What are the characteristics of acute invasive pulmonary aspergillosis?
Rapid and extensive hyphal growth
Thrombosis and hemorrhage
Angio-invasive and dissemination
Absent or non-specific clinical signs and symptoms
Persistent febrile neutropenia despite broad-spectrum antibiotics
Mortality rates around 50% (depending on immune recovery)
What are the characteristics of sub-acute invasive pulmonary aspergillosis?
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%
For which immunodeficiencies can invasive aspergillosis be a presenting symptom?
Congenital neutropenia
Chronic granulomatous disease
Hyper IgE syndrome
CARD-9 deficiency
What are the characteristics of chronic pulmonary aspergillosis?
Pulmonary exacerbations that do not respond to antibiotics
Lung function decline
Respiratory symptoms such as cough, decreased exercise tolerance and dyspnoea
Positive sputum cultures for aspergillus
What hosts are affected by each classification of aspergillosis infection?
Acute invasive pulmonary aspergillosis-neutropenic hosts
Sub-acute invasive pulmonary aspergillosis- non-neutropenic hosts
Chronic pulmonary aspergillosis- hosts with asthma, cystic fibrosis or any other chronic obstructive lung disease
What are the characteristics of allergic bronchopulmonary aspergillosis?
Immunological responses to a variety of A. fumigatus antigens in the CF-host (10-15%) result in:
Acute/subacute deterioration of lung function and respiratory symptoms
New abnormalities chest imaging
Elevated immunoglobulin E (IgE) level
Increased Aspergillus specific IgE or positive skin-test
Positive Aspergillus specific IgG
What is a pulmonary aspergilloma?
Fungal mass that usually grows in lung cavities
Most commonly due to TB but can also be caused by sarcoidosis, bronchiectasis, bronchial cysts/bullae or any other pulmonary infection
