Fungal Infections Flashcards
Number of fungal infections of humans per year
1.5 billion fungal infections of humans
> 3 million life-threatening infections per year
Mortality rates of invasive fungal infection
> 50%
Number of cases of blindness caused by fungal infections each year
> 400,000 per year
Number of exacerbations of asthma and allergies (and other chronic lung disease) caused by fungal pathogens each year
> 20 million
Global mortality figures for invasive fungal infections, TB and malaria
Invasive fungal infections - 1,350,000
TB - 1,400,000
Malaria - 1,240,000
Common fungal pathogens
Aspergillus species
Candida species
Cryptococcus species
What patients are typically affected by fungal infections?
Impaired immune systems e.g. HIV AIDS Premature neonates Malignancies Transplants
Why do fungal infections affect patients in an ICU setting?
Due to use of broad spectrum antibiotics and the need to use intravascular catheters i.e. normal mucosal barriers being compromised
Also due to multi-system disease
What should be considered in a serious fungal infection of an otherwise health individual?
Underlying undiagnosed immunodeficiency
Predisposing factors for mucocutaneous candidiasis
Can affect both healthy and immunocompromised individuals
Inhalation steroids
Antibiotic treatments
Patients generally affected by mucocutaneous candidiasis
Neonates < 3 months
Primary immunodeficiency
Elderly
What is the fourth most common blood stream infection?
Invasive candidiasis
When would an anti fungal be given for a blood stream infection?
Presentation of fungal BSI is the same as bacterial BSI, so anti fungal would be given at failure to improve on antibiotic
Mortality of invasive candidiasis
up to 40%
Risk factors for invasive candidiasis
Use of broad spectrum antibiotics
Intravascular catheters
Total parenteral nutrition
Transmission of aspergillus and aspergillosis
Transmission by sporulation, airborne, inhalation
Patients affected by acute invasive pulmonary aspergillosis
Neutropenic patients
Defects in phagocytes
Acquired, congenital or acute diseases with high mortality rates
Patients affected by chronic pulmonary aspergillosis (> 3 months)
Patients with underlying chronic lung conditions e.g. asthma, COPD
What is the difference between acute and chronic pulmonary aspergillosis?
Acute is more severe, chronic is milder but will lead to progressive decline in lung function
Forms of allergic aspergillosis
Allergic bronchopulmonary aspergillosis
Extrinsic allergic bronchoalveolitis
Asthma or CF with fungal sensation
Why is allergic aspergillosis a challenge to treat clinically?
Have to balance between steroids for the allergy and anti-fungals for the infection
Patients affected by acute invasive pulmonary aspergillosis
Neutropenic hosts e.g. acute leukaemia, HSCT, post-bone marrow transplant
Pathophysiology of acute invasive pulmonary aspergillosis
Rapid and extensive hyphal growth
Thrombosis and haemorrhage
Angio-invasion and dissemination
Presentation of acute invasive pulmonary aspergillosis
Absent or non-specific clinical signs and symptoms
Persistent febrile neutropenia despite broad spectrum antibiotics
Mortality rates of acute invasive pulmonary aspergillosis
50-90% due to the inability to reverse the causative/predisposing immune deficiency
Patients affected by pulmonary aspergilloma
TB Sarcoidosis Bronchiectasis Bronchial cysts and bullae After pulmonary infections
What is pulmonary aspergilloma?
A fungal mass, usually grows in lung cavities
Transmission of cryptococcus and cryptococcosis
Inhalation
Found on bark of trees, in bird faeces and in organic matter
What patients are susceptible to cryptococcal meningitis?
HIV/AIDS patients
When might subacute meningoencephalitis occur?
After latent cryptococcal infection
Mortality of cryptococcosis in the US and in Africa
25% in US
70% in Africa
Diagnosis of cryptococcal infection
India-ink CSF
Anti-fungal treatment for invasive aspergillosis
Voriconazole or isavuconazole IV or oral formulation
Liposomal amphotericin B IV only (second line)
Anti-fungal treatment for invasive candidiasis
Echinocandins IV only
Fluconazole IV or oral formulation (second line)
Anti-fungal treatment for cryptococcal meningitis
Amphotericin B and Flucytosine followed by fluconazole
Resistance of candida auras to fluconazole, echinocandin, amphotericin and multi-drug
Fluconazole - 90% resistant
Echinocandin - 30-40% resistant
Amphotericin - 5-15% resistant
50% multi-drug resistant
