Infectious Diseases

Question 1

Antifungals: polyenes

Answer 1

MOA: perforates fungal cell membrane
Broad spectrum
E.g. amphotericin, nystatin
SE: nephrotoxic

Question 2

Antifungals: echinocandins

Answer 2

MOA: inhibits cell wall synthesis, especially Beta 1,3 D glucan synthesis
Well tolerated, does not penetrate CSF or urine
E.g. caspofungin, micafungin

Question 3

Antifungals: azoles

Answer 3

MOA: interferes with cell membrane synthesis (ergosterol)
Triazoles: fluconazole (C. albicans), voriconazole (Aspergillus fumigatus)
Imidazoles: clotrimazole, miconazole
SE: induces CYP450 –> hepatotoxicity

Question 4

In an immunosuppressed patient, prolonged fever and neutropenia - antifungal choice

Answer 4

1. Amphotericin
2. Fluconazole (low risk)
3. Caspofungin

Question 5

Candidaemia or invasive candida infection - antifungal choice

Answer 5

1. Fluconazole
2. Amphotericin B
3. Caspofungin

Question 6

Invasive aspergillus infection - antifungal choice

Answer 6

1. Voriconazole
2. Amphotericin B
3. Caspofungin

Question 7

Ganciclovir resistance genes

Answer 7

UL97 and UL54

Question 8

Clinical features of CMV infection in HSCT patient

Answer 8

Most at risk 1-4mo post-HSCT
Most fatal: pneumonitis
Fever, retinitis, pneumonitis, oesophagitis, gastritis, hepatitis, colitis
Pancytopenia, leukopenia, thrombocytopenia

Question 9

Side effects of antiviral agents to treat CMV

Answer 9

First line: ganciclovir 
- Neutropenia, suppresses T cell function
- Other main issue with ganciclovir = resistance
Second line: foscarnet
- Significant nephrotoxicity 
- GCV-resistant CMV
Third line: cidofovir
- Significant nephrotoxicity