228 Fungal disease

Question 1

Which sterol is found in fungal plasma membranes?

Answer 1

Ergosterol

Question 2

Which polysaccharide is found in the cell walls of fungi?

Answer 2

Chitin

Question 3

What is the benefit of having seperate cells/compartments in a fungi?

Answer 3

Damaged cells can be separated off and shed

Question 4

What form are yeasts in when causing infection?

Answer 4

pseudohyphal

Question 5

What substance do vacuoles produce which contributes to the fungal virulence?

Answer 5

Exoenzymes

Question 6

What are:
Histoplasmosis
Coccidiomycosis
Blastomycosis
Paracoccidioidomycosis
                                      examples of?

Answer 6

‘True’ fungal pathogens usually associated with travel

Question 7

What is the mortality rate in immunodeficient patients with invasive candidiasis?

Answer 7

30%

Question 8

What is a Wood’s lamp used for?

Answer 8

To see the fluorescence of certain micro-organisms

Question 9

What is hypersensitivity pneumonitis?

Answer 9

Mix of type 3 and 4 hypersensitivity reactions causing inflammation in the lungs

Question 10

Why is KOH used to stain for fungi?

Answer 10

It dissolves everything but chitin so fungal cells are easily visualised

Question 11

Which type of hypersensitivity reaction can cause formation of granulomas?

Answer 11

Type 4 - recruitment of macrophages by lymphocytes which become highly active causing cell damage with the products they release

Question 12

What is released by the hyphae in a mycetoma causing haemoptysis?

Answer 12

Oxalic acid - causes erosion of bv’s

Question 13

What is released by aspergillus and causes hepatocellular carcinoma in Asia?

Answer 13

Aflatoxin

Question 14

What is a mycetoma?

Answer 14

Ball of fungus within an old cavitating lesion e.g. old TB/abscess

Question 15

Which antifungals are used to treat invasive aspergillosis?

Answer 15

Amphotericin

Flucytosine

Question 16

What is dhobi itch?

Answer 16

Tinea cruris

Question 17

Which part of the body does tinea Manuum affect?

Answer 17

Hands

Question 18

Which part of the boy does tinea unguium affect?

Answer 18

Nails

Question 19

What are the 2 classes of azoles? (antifungals)

Answer 19

Imidazoles

Triazoles

Question 20

Which category of azoles do topical azoles adn ketoconazole come under?
Imidazoles
Triazoles

Answer 20

Imidazoles

Question 21

What is the MOA of azoles?

Answer 21

Inhibition of fungal cytochrome P450 which results in decrease of ergosterol and accumulation of toxic intermediates.

Question 22

Which species of fungi is fluconazole active against?

Answer 22

Candida spp
Cryptococcus spp
Dermatophytes

Question 23

Which species of fungi is voriconazole active against?

Answer 23

Aspergillus

Candida spp

Question 24

Which enzyme does caspofungin inhibits in the fungal cell wall?

Answer 24

1, 3 beta glucan synthase

Question 25

Which antifungal inhibits squalene epoxidase subsequently inhibiting the synthesis of ergosterol?

Answer 25

terbinafine

Question 26

Where in the body does terbinafine concentrate - what type of infections does it treat?

Answer 26

Superficial dermatophyte infections

Question 27

Which antifungal is 90% protein bound and highly toxic (can cause renal impairment and hypokalaemia)?

1. Fluconazole
2. Amphotericin
3. Caspofungin

Answer 27

Amphotericin

Question 28

What is the MOA of amphotericin?

Answer 28

Binds to ergosterol in the membrane and forms pores which causes leakage of cations –> cell death

Question 29

Which antifungal converts to 5-fluorouracil in fungal cells to inhibit DNA synthesis?

1. Flucytosine
2. Griseofulvin
3. Voriconazole

Answer 29

flucytosine

Question 30

What is flucytosine used for?

Answer 30

Antifungal which is used in combination with other drugs to decrease resistance.

Question 31

Which antifungal interacts with microtubules and interferes with mitosis?

1. Flucytosine
2. Griseofulvin
3. Voriconazole

Answer 31

Griseofulvin